Crypto Framework Development

NOTE

This guide applies only to JavaScript development using the SDK of API version 9 or later.

Key Generation and Conversion

When to Use

Typical key generation operations involve the following:

1. Randomly create a key object for subsequent encryption and decryption.
2. Create a key object based on the specified key parameters for subsequent encryption and decryption.
3. Convert external or internal binary data into a key object for subsequent encryption and decryption.
4. Obtain the binary data of a key object for storage or transmission.
5. Obtain the parameter properties of an asymmetric key object for storage or transmission.

NOTE

The key object can be a symmetric key object (SymKey) or an asymmetric key pair object (KeyPair). The KeyPair object consists a public key (PubKey) and a private key (PriKey). For details about the relationship between the keys, see Crypto Framework.

Available APIs

The following table describes the APIs used in typical key generation operations. For more information about the APIs, see Crypto Framework.

Randomly Generating an RSA Key Pair and Obtaining the Binary Data

Randomly generate an asymmetric key pair and obtain its binary data.

1. Create an AsyKeyGenerator instance.
2. Randomly generate an asymmetric key pair using AsyKeyGenerator.
3. Obtain the binary data of the key pair generated.

Example: Randomly generate an RSA key (1024 bits and two primes) in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function generateAsyKey() {
  // Create an AsyKeyGenerator instance.
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator('RSA1024|PRIMES_2');
  // Use the key generator to randomly generate an asymmetric key pair.
  let keyGenPromise = rsaGenerator.generateKeyPair();
  keyGenPromise.then(keyPair => {
    let pubKey = keyPair.pubKey;
    let priKey = keyPair.priKey;
    // Obtain the binary data of the asymmetric key pair.
    let pkBlob = pubKey.getEncoded();
    let skBlob = priKey.getEncoded();
    AlertDialog.show({ message: 'pk bin data' + pkBlob.data });
    AlertDialog.show({ message: 'sk bin data' + skBlob.data });
  })
}

Randomly Generating an AES Key and Obtaining the Binary Data

Randomly generate a symmetric key and obtain its binary data.

1. Create a SymKeyGenerator instance.
2. Randomly generate a symmetric key using SymKeyGenerator.
3. Obtain the binary data of the key generated.

Example: Randomly generate an AES key (256 bits) in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function testGenerateAesKey() {
  // Create a SymKeyGenerator instance.
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator('AES256');
  // Use the key generator to randomly generate a symmetric key.
  let promiseSymKey = symKeyGenerator.generateSymKey();
  promiseSymKey.then(key => {
    // Obtain the binary data of the symmetric key and output the 256-bit key. The length is 32 bytes.
    let encodedKey = key.getEncoded();
    console.info('key hex:' + encodedKey.data);
  })
}

Converting Binary Data into an RSA Key Pair

Generate an RSA asymmetric key pair from the binary data.

1. Obtain the binary data of the RSA public or private key. The public key must comply with the ASN.1 syntax, X.509 specifications, and DER encoding format. The private key must comply with the ASN.1 syntax, PKCS #8 specifications, and DER encoding format.
2. Create an AsyKeyGenerator instance, and use convertKey() to convert the key binary data (data of the private or public key, or both) into a KeyPair instance.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function convertAsyKey() {
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator('RSA1024');
  let pkVal = new Uint8Array([48, 129, 159, 48, 13, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 1, 5, 0, 3, 129, 141, 0, 48, 129, 137, 2, 129, 129, 0, 174, 203, 113, 83, 113, 3, 143, 213, 194, 79, 91, 9, 51, 142, 87, 45, 97, 65, 136, 24, 166, 35, 5, 179, 42, 47, 212, 79, 111, 74, 134, 120, 73, 67, 21, 19, 235, 80, 46, 152, 209, 133, 232, 87, 192, 140, 18, 206, 27, 106, 106, 169, 106, 46, 135, 111, 118, 32, 129, 27, 89, 255, 183, 116, 247, 38, 12, 7, 238, 77, 151, 167, 6, 102, 153, 126, 66, 28, 253, 253, 216, 64, 20, 138, 117, 72, 15, 216, 178, 37, 208, 179, 63, 204, 39, 94, 244, 170, 48, 190, 21, 11, 73, 169, 156, 104, 193, 3, 17, 100, 28, 60, 50, 92, 235, 218, 57, 73, 119, 19, 101, 164, 192, 161, 197, 106, 105, 73, 2, 3, 1, 0, 1]);
  let pkBlob: cryptoFramework.DataBlob = { data: pkVal };
  rsaGenerator.convertKey(pkBlob, null, (err, keyPair) => {
    if (err) {
      AlertDialog.show({ message: 'Convert keyPair fail' });
      return;
    }
    AlertDialog.show({ message: 'Convert keyPair success' });
  })
}

NOTE

The public key binary data to be converted by convertKey() must be in the DER format complying with X.509 specifications, and the private key binary data must be in the DER format complying with PKCS #8 specifications.

Converting Binary Data into an ECC Key Pair

Generate an ECC asymmetric key pair from the binary data.

1. Obtain the ECC binary key data and encapsulate it into a DataBlob instance.
2. Use convertKey() to convert the binary data (data of the private or public key, or both) into a KeyPair instance.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function convertEccAsyKey() {
  let pubKeyArray = new Uint8Array([48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7, 3, 66, 0, 4, 83, 96, 142, 9, 86, 214, 126, 106, 247, 233, 92, 125, 4, 128, 138, 105, 246, 162, 215, 71, 81, 58, 202, 121, 26, 105, 211, 55, 130, 45, 236, 143, 55, 16, 248, 75, 167, 160, 167, 106, 2, 152, 243, 44, 68, 66, 0, 167, 99, 92, 235, 215, 159, 239, 28, 106, 124, 171, 34, 145, 124, 174, 57, 92]);
  let priKeyArray = new Uint8Array([48, 49, 2, 1, 1, 4, 32, 115, 56, 137, 35, 207, 0, 60, 191, 90, 61, 136, 105, 210, 16, 27, 4, 171, 57, 10, 61, 123, 40, 189, 28, 34, 207, 236, 22, 45, 223, 10, 189, 160, 10, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7]);
  let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyArray };
  let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyArray };
  let generator = cryptoFramework.createAsyKeyGenerator('ECC256');
  generator.convertKey(pubKeyBlob, priKeyBlob, (error, data) => {
    if (error) {
      AlertDialog.show({ message: 'Convert keyPair fail' });
      return;
    }
    AlertDialog.show({ message: 'Convert keyPair success' });
  })
}

Converting Binary Data into a 3DES Key

Generate a symmetric key from the binary key data.

1. Create a SymKeyGenerator instance.
2. Convert the binary data into a SymKey instance.
3. Obtain the binary data of the key instance generated.

Example: Generate a 3DES key (192 bits only) in callback mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function genKeyMaterialBlob(): cryptoFramework.DataBlob {
  let arr = [
    0xba, 0x3d, 0xc2, 0x71, 0x21, 0x1e, 0x30, 0x56,
    0xad, 0x47, 0xfc, 0x5a, 0x46, 0x39, 0xee, 0x7c,
    0xba, 0x3b, 0xc2, 0x71, 0xab, 0xa0, 0x30, 0x72]; // keyLen = 192 (24 bytes)
  let keyMaterial = new Uint8Array(arr);
  return { data: keyMaterial };
}

function testConvertSymKey() {
  // Create a SymKeyGenerator instance.
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator('3DES192');
  // Generate a symmetric key based on the specified data.
  let keyMaterialBlob = genKeyMaterialBlob();
  try {
    symKeyGenerator.convertKey(keyMaterialBlob, (error, key) => {
      if (error) { // If the service logic fails to be executed, the first parameter of callback returns error information, that is, an exception is thrown asynchronously.
        let e: BusinessError = error as BusinessError;
        console.error(`convertKey error, ${e.code}, ${e.message}`);
        return;
      }
      console.info(`key algName: ${key.algName}`);
      console.info(`key format: ${key.format}`);
      let encodedKey = key.getEncoded(); // Obtain the binary data of the symmetric key and output in bytes array. The length is 24 bytes.
      console.info('key getEncoded hex: ' + encodedKey.data);
    })
  } catch (error) { // Throw an exception immediately when an error is detected in parameter check.
    let e: BusinessError = error as BusinessError;
    console.error(`convertKey failed, ${e.code}, ${e.message}`);
    return;
  }
}

Randomly Generating an SM2 Key Pair and Obtaining the Binary Data

NOTE

SM2 asymmetric keys can be randomly generated from API version 10.

Randomly generate an asymmetric key pair and obtain its binary data.

1. Create an AsyKeyGenerator instance.
2. Randomly generate an asymmetric key pair using AsyKeyGenerator.
3. Obtain the binary data of the key pair generated.

Example: Randomly generate an SM2 key (256 bits) in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function generateSM2Key() {
  // Create an AsyKeyGenerator instance.
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  // Use the key generator to randomly generate an asymmetric key pair.
  let keyGenPromise = sm2Generator.generateKeyPair();
  keyGenPromise.then(keyPair => {
    let pubKey = keyPair.pubKey;
    let priKey = keyPair.priKey;
    // Obtain the binary data of the asymmetric key pair.
    let pkBlob = pubKey.getEncoded();
    let skBlob = priKey.getEncoded();
    AlertDialog.show({ message: "pk bin data" + pkBlob.data });
    AlertDialog.show({ message: "sk bin data" + skBlob.data });
  })
}

Randomly Generating an SM4 Key and Obtaining the Binary Data

NOTE

SM4 keys can be randomly generated from API version 10.

Randomly generate a symmetric key and obtain its binary data.

1. Create a SymKeyGenerator instance.
2. Randomly generate a symmetric key using SymKeyGenerator.
3. Obtain the binary data of the key generated.

Example: Randomly generate an SM4 key (128 bits) in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function testGenerateSM4Key() {
  // Create a SymKeyGenerator instance.
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("SM4_128");
  // Use the key generator to randomly generate a symmetric key.
  let promiseSymKey = symKeyGenerator.generateSymKey();
  promiseSymKey.then(key => {
    // Obtain the binary data of the symmetric key and output a 128-bit byte stream. The length is 16 bytes.
    let encodedKey = key.getEncoded();
    console.info('key hex:' + encodedKey.data);
  })
}

Converting Binary Data into an SM2 Key Pair

NOTE

SM2 key conversion is supported from API version 10.

Generate an SM2 asymmetric key pair from the given binary key data.

1. Obtain the SM2 binary key data and encapsulate it into a DataBlob instance.
2. Call convertKey() to convert the binary data (data of the private or public key, or both) into a KeyPair instance.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function convertSM2AsyKey() {
  let pubKeyArray = new Uint8Array([48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 129, 28, 207, 85, 1, 130, 45, 3, 66, 0, 4, 90, 3, 58, 157, 190, 248, 76, 7, 132, 200, 151, 208, 112, 230, 96, 140, 90, 238, 211, 155, 128, 109, 248, 40, 83, 214, 78, 42, 104, 106, 55, 148, 249, 35, 61, 32, 221, 135, 143, 100, 45, 97, 194, 176, 52, 73, 136, 174, 40, 70, 70, 34, 103, 103, 161, 99, 27, 187, 13, 187, 109, 244, 13, 7]);
  let priKeyArray = new Uint8Array([48, 49, 2, 1, 1, 4, 32, 54, 41, 239, 240, 63, 188, 134, 113, 31, 102, 149, 203, 245, 89, 15, 15, 47, 202, 170, 60, 38, 154, 28, 169, 189, 100, 251, 76, 112, 223, 156, 159, 160, 10, 6, 8, 42, 129, 28, 207, 85, 1, 130, 45]);
  let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyArray };
  let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyArray };
  let generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  generator.convertKey(pubKeyBlob, priKeyBlob, (error, data) => {
    if (error) {
      AlertDialog.show({ message: "Convert keypair fail" });
      return;
    }
    AlertDialog.show({ message: "Convert KeyPair success" });
  })
}

Randomly Generating an HMAC Key and Obtaining the Binary Data

NOTE

From API version 11, HMAC keys can be generated randomly.

Randomly generate a symmetric key SymKey for the HMAC algorithm and obtain the binary data.

1. Create a SymKeyGenerator instance.
2. Use the symmetric key generator to randomly generate a symmetric key for the HMAC algorithm.
3. Obtain the binary data of the key generated.

Example: Randomly generate an HMAC key (256 bits) in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';

function testGenerateHmacKey() {
  // Create a SymKeyGenerator instance.
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("HMAC|SHA256");
  // Use the key generator to randomly generate a symmetric key.
  let promiseSymKey = symKeyGenerator.generateSymKey();
  promiseSymKey.then(key => {
    // Obtain the binary data of the symmetric key and output a 256-bit byte stream. The length is 32 bytes.
    let encodedKey = key.getEncoded();
    console.info('key hex:' + encodedKey.data);
  })
}

Converting Binary Data into an HMAC Key

NOTE

From API version 11, HMAC key conversion is supported.

Generate a symmetric key SymKey for the HMAC algorithm based on the specified HMAC symmetric key binary data.

1. Create a SymKeyGenerator instance.
2. Use the symmetric key generator to generate a SymKey object based on the specified HMAC binary key data.

NOTE

1. If HMAC is used to create a symmetric key generator, the binary key data of 1 to 4096 bytes can be passed in to generate a symKey.
2. If HMAC|SHA512 is used to create a symmetric key generator, binary key data of 64 bytes must be passed in to generate a symKey.

Example: Generate an HMAC key in callback mode (using SHA512 as the hash function).

import cryptoFramework from '@ohos.security.cryptoFramework';

function stringToUint8Array(str) {
  let arr = [];
  for (let i = 0, j = str.length; i < j; ++i) {
    arr.push(str.charCodeAt(i));
  }
  let tmpUint8Array = new Uint8Array(arr);
  return tmpUint8Array;
}

function testConvertHmacKey() {
  let keyBlob = {
    // The length is 512-bit (64 bytes).
    data : stringToUint8Array("12345678abcdefgh12345678abcdefgh12345678abcdefgh12345678abcdefgh")
  }
  // Create a SymKeyGenerator instance.
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("HMAC");
  symKeyGenerator.convertKey(keyBlob, (error, symKey) => {
    if (error) {
      console.info('Convert symKey fail!');
      return;
    }
    console.info('Convert symKey success!');
  })
}

Generating an Asymmetric Key Object and Obtaining Key Parameters

When to Use

Typical key generation operations involve the following: 1. Create a key object based on the specified asymmetric key parameters for subsequent encryption and decryption. 2. Obtain the parameter properties of an asymmetric key object for storage or transmission.

NOTE

• Key parameters can be used to generate asymmetric keys from API version 10.
• Asymmetric systems use a public key (PubKey) to encrypt data and a related private key (PriKey) to decrypt it. The public key and private key form a key pair (KeyPair). For details about asymmetric key parameters, see Crypto Framework.

Available APIs

The following table describes the APIs used in typical key generation operations. For more information about the APIs, see AsyKeyGeneratorBySpec.

Generating an ECC Key Pair and Obtaining Key Specifications

Generate an ECC key pair based on parameters and obtain the key specifications.

1. Create an AsyKeyGenerator based on key parameters.
2. Use the AsyKeyGenerator to generate an asymmetric key pair based on the specified key parameters.
3. Obtain the key specifications of a key object.

Example: Generate an ECC key based on key parameters in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';

// Print bigint information.
function showBigIntInfo(bnName: string, bnValue: bigint|string|number) {
  if (typeof bnValue === 'string') {
    console.error('type is string');
    return;
  }
  if (typeof bnValue === 'number') {
    console.error('type is number');
    return;
  }
  console.info(bnName + ":");
  console.info(". Decimal: " + bnValue.toString());
  console.info(". Hexadecimal: " + bnValue.toString(16));
  console.info(". Length (bits): " + bnValue.toString(2).length);
}

// Construct the EccCommonSpec struct based on the key specifications. The EccCommonSpec struct defines the common parameters of the ECC private key and public key.
function genEccCommonSpec(): cryptoFramework.ECCCommonParamsSpec {
  let fieldFp: cryptoFramework.ECFieldFp = {
    fieldType: "Fp",
    p: BigInt("0xffffffffffffffffffffffffffffffff000000000000000000000001")
  }

  let G: cryptoFramework.Point = {
    x: BigInt("0xb70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21"),
    y: BigInt("0xbd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34")
  }

  let eccCommonSpec: cryptoFramework.ECCCommonParamsSpec = {
    algName: "ECC",
    specType: cryptoFramework.AsyKeySpecType.COMMON_PARAMS_SPEC,
    field: fieldFp,
    a: BigInt("0xfffffffffffffffffffffffffffffffefffffffffffffffffffffffe"),
    b: BigInt("0xb4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4"),
    g: G,
    n: BigInt("0xffffffffffffffffffffffffffff16a2e0b8f03e13dd29455c5c2a3d"),
    h: 1
  }
  return eccCommonSpec;
}

// Print the ECC key specifications.
function showEccSpecDetailInfo(key: cryptoFramework.PubKey|cryptoFramework.PriKey, keyType: string) {
  console.info("show detail of " + keyType + ":");
  try {
    let p = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_FP_P_BN);
    showBigIntInfo("--- p", p); // length is 224, hex : ffffffffffffffffffffffffffffffff000000000000000000000001

    let a = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_A_BN);
    showBigIntInfo("--- a", a); // length is 224, hex : fffffffffffffffffffffffffffffffefffffffffffffffffffffffe

    let b = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_B_BN);
    showBigIntInfo("--- b", b); // length is 224, hex : b4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4

    let gX = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_G_X_BN);
    showBigIntInfo("--- gX", gX); // length is 224, hex : b70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21

    let gY = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_G_Y_BN);
    showBigIntInfo("--- gY", gY); // length is 224, hex : bd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34

    let n = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_N_BN);
    showBigIntInfo("--- n", n); // length is 224, hex : ffffffffffffffffffffffffffff16a2e0b8f03e13dd29455c5c2a3d

    let h = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_H_NUM);
    console.warn("--- h: " + h); // key h: 1

    let fieldType = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_FIELD_TYPE_STR);
    console.warn("--- field type: " + fieldType); // key field type: Fp

    let fieldSize = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_FIELD_SIZE_NUM);
    console.warn("--- field size: " + fieldSize); // key field size: 224

    let curveName = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_CURVE_NAME_STR);
    console.warn("--- curve name: " + curveName); // key curve name: NID_secp224r1

    if (keyType == "priKey") {
      let sk = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_SK_BN);
      showBigIntInfo("--- sk", sk);
    } else if (keyType == "pubKey") {
      let pkX = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_PK_X_BN);
      showBigIntInfo("--- pkX", pkX);
      let pkY = key.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.ECC_PK_Y_BN);
      showBigIntInfo("--- pkY", pkY);
    }
  } catch (error) {
    console.error("getAsyKeySpec error");
    let e: BusinessError = error as BusinessError;
    console.error(`getAsyKeySpec failed, ${e.code}, ${e.message}`);
  }
}

// Generate an ECC key pair based on the EccCommonSpec instance and obtain the key specifications.
function testEccUseCommKeySpecGet() {
  try {
    let commKeySpec = genEccCommonSpec(); // Construct the EccCommonSpec object.
    let generatorBySpec = cryptoFramework.createAsyKeyGeneratorBySpec(commKeySpec); // Create an AsyKeyGenerator instance based on the EccCommonSpec object.
    let keyPairPromise = generatorBySpec.generateKeyPair(); // Generate an ECC key pair.
    keyPairPromise.then(keyPair => {
      showEccSpecDetailInfo(keyPair.priKey, "priKey"); // Obtain the ECC specifications of the private key.
      showEccSpecDetailInfo(keyPair.pubKey, "pubKey"); // Obtain the ECC specifications of the public key.
    }).catch((error: BusinessError) => {
      // Capture exceptions such as logic errors asynchronously here.
      console.error("generateComm error");
      console.error("error code: " + error.code + ", message is: " + error.message);
    })
  } catch (error) {
    // Capture parameter errors synchronously here.
    console.error("testEccUseCommSpec error");
    let e: BusinessError = error as BusinessError;
    console.error(`ecc comm spec failed, ${e.code}, ${e.message}`);
  }
}

Generating an RSA Public Key and Obtaining Key Specifications

Generate an RSA public key based on parameters and obtain key specifications.

1. Create an AsyKeyGenerator based on key parameters.
2. Use the AsyKeyGenerator to generate the public key of an asymmetric key pair.
3. Obtain the key specifications of the public key object.

Example: Generate an RSA public key based on key parameters in callback mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';
// Generate RSA public key specifications.
function genRsaPubKeySpec(nIn: bigint, eIn: bigint): cryptoFramework.RSAPubKeySpec {
  let rsaCommSpec: cryptoFramework.RSACommonParamsSpec = {
    n: nIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.COMMON_PARAMS_SPEC
  };
  let rsaPubKeySpec: cryptoFramework.RSAPubKeySpec = {
    params: rsaCommSpec,
    pk: eIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.PUBLIC_KEY_SPEC
  };
  return rsaPubKeySpec;
}

// Construct an RSA public key specifications object based on the key parameters.
function genRsa2048PubKeySpec() {
  let nIn = BigInt("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");
  let eIn = BigInt("0x010001");
  return genRsaPubKeySpec(nIn, eIn);
}

// Compare the RSA public key specifications with the expected values.
function compareRsaPubKeyBySpec(rsaKeySpec: cryptoFramework.RSAPubKeySpec, n: bigint|string|number, e: bigint|string|number) {
  if (typeof n === 'string'||typeof e === 'string') {
    console.error('type is string');
    return false;
  }
  if (typeof n === 'number'||typeof e === 'number') {
    console.error('type is number');
    return false;
  }
  if (rsaKeySpec.params.n != n) {
    return false;
  }
  if (rsaKeySpec.pk != e) {
    return false;
  }
  return true;
}

// Generate an RSA public key based on the RSA public key specifications, obtain the key specifications, and compare the key specifications with the expected values.
function rsaUsePubKeySpecGetCallback() {
  let rsaPubKeySpec = genRsa2048PubKeySpec();
  let rsaGeneratorSpec = cryptoFramework.createAsyKeyGeneratorBySpec(rsaPubKeySpec);
  rsaGeneratorSpec.generatePubKey((error, key) => {
    let pubKey = key;
    let nBN = pubKey.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.RSA_N_BN);
    let eBN = pubKey.getAsyKeySpec(cryptoFramework.AsyKeySpecItem.RSA_PK_BN);
    if (compareRsaPubKeyBySpec(rsaPubKeySpec, nBN, eBN) != true) {
      AlertDialog.show({ message: "error pub key big number" });
    } else {
      console.info("n, e in the pubKey are same as the spec.");
    }
    if (error) {
      console.error("generate pubKey error" + "error code: " + error.code + "error message" + error.message);
    }
  });
}

Encryption and Decryption

When to Use

Important data needs to be encrypted in data storage or transmission for security purposes. Typical encryption and decryption operations involve the following: 1. Encrypt and decrypt data using a symmetric key. 2. Encrypt and decrypt data using an asymmetric key pair. 3. Obtain and set the CipherSpecItem parameter when the PKCS1_OAEP padding mode is used in RSA.

NOTE

• From API version 10, CipherSpecItem can be obtained and set when the PKCS1_OAEP padding mode is used in RSA.
• From API version 10, the string parameter without the key length is supported in encryption and decryption.

Available APIs

The following table describes the APIs used in the typical encryption and decryption operations. For details about the APIs, see Crypto Framework. > NOTE > > Due to complexity of cryptographic algorithms, the implementation varies depending on the key specifications and parameters you use, and cannot be enumerated by sample code. Before you start, understand the APIs to ensure correct use of these APIs.

Encrypting and Decrypting Data Using AES GCM (Promise)

Encrypt and decrypt data using an AES symmetric key.

1. Create a SymKeyGenerator instance.
2. Use the SymKeyGenerator to randomly generate a symmetric key.
3. Create a Cipher instance.
4. Encrypt or decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function genGcmParamsSpec() {
  let arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; // 12 bytes
  let dataIv = new Uint8Array(arr);
  let ivBlob: cryptoFramework.DataBlob = { data: dataIv };

  arr = [0, 0, 0, 0, 0, 0, 0, 0]; // 8 bytes
  let dataAad = new Uint8Array(arr);
  let aadBlob: cryptoFramework.DataBlob = { data: dataAad };

  arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; // 16 bytes
  let dataTag = new Uint8Array(arr);
  let tagBlob: cryptoFramework.DataBlob = {
    data: dataTag
  }; // The GCM authTag is obtained by doFinal() in encryption and passed in params of init() in decryption.

  let gcmParamsSpec: cryptoFramework.GcmParamsSpec = {
    iv: ivBlob,
    aad: aadBlob,
    authTag: tagBlob,
    algName: "GcmParamsSpec"
  };
  return gcmParamsSpec;
}

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

// Automatically generate an AES GCM key in promise mode.
function testAesGcm() {
  let symAlgName = 'AES128';
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName);
  console.info(`symKeyGenerator algName: ${symKeyGenerator.algName}`);
  // Generate GCM parameter specifications.
  let globalGcmParams = genGcmParamsSpec();
  // Create a Cipher instance.
  let cipherAlgName = 'AES128|GCM|PKCS7';
  let globalCipher = cryptoFramework.createCipher(cipherAlgName);
  console.info(`cipher algName: ${globalCipher.algName}`);
  // Use the key generator to randomly generate a 128-bit symmetric key.
  let globalCipherText: cryptoFramework.DataBlob;
  let globalKey: cryptoFramework.SymKey;
  let promiseSymKey = symKeyGenerator.generateSymKey();
  promiseSymKey.then(key => {
    // Initialize the Cipher instance and start encryption.
    globalKey = key;
    let mode = cryptoFramework.CryptoMode.ENCRYPT_MODE;
    return globalCipher.init(mode, globalKey, globalGcmParams);
  })
    .then(() => {
      let plainText: cryptoFramework.DataBlob = { data: stringToUint8Array('this is test!') };
      return globalCipher.update(plainText);
    })
    .then((updateOutput: cryptoFramework.DataBlob): Promise<cryptoFramework.DataBlob> => {
      globalCipherText = updateOutput;
      return globalCipher.doFinal(null);
    })
    .then(tag => {
      // In GCM mode, the encrypted authentication information needs to be obtained from the output of doFinal() and passed in globalGcmParams of init() in decryption.
      globalGcmParams.authTag = tag;
      return;
    })
    .then(() => {
      // Initialize the Cipher instance and start decryption.
      let mode = cryptoFramework.CryptoMode.DECRYPT_MODE;
      return globalCipher.init(mode, globalKey, globalGcmParams);
    })
    .then(() => {
      return globalCipher.update(globalCipherText); // update
    })
    .then((updateOutput: cryptoFramework.DataBlob): Promise<cryptoFramework.DataBlob> => {
      console.info('decrypt plainText: ' + uint8ArrayToString(updateOutput.data));
      return globalCipher.doFinal(null);
    })
    .then(finalOutput => {
      if (finalOutput == null) { // Check whether the result is null before using finalOutput.data.
        console.info('GCM finalOutput is null');
      }
    })
    .catch((error: BusinessError) => {
      console.error(`catch error, ${error.code}, ${error.message}`);
    })
}

Encrypting and Decrypting Data Using a 3DES ECB Symmetric Key (Callback)

Encrypt and decrypt data using a 3DES symmetric key.

1. Create a SymKeyGenerator instance.
2. Generate a key based on the existing binary data.
3. Create a Cipher instance.
4. Encrypt or decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

function genKeyMaterialBlob(): cryptoFramework.DataBlob {
  let arr = [
    0xba, 0x3d, 0xc2, 0x71, 0x21, 0x1e, 0x30, 0x56,
    0xad, 0x47, 0xfc, 0x5a, 0x46, 0x39, 0xee, 0x7c,
    0xba, 0x3b, 0xc2, 0x71, 0xab, 0xa0, 0x30, 0x72]; // keyLen = 192 (24 bytes)
  let keyMaterial = new Uint8Array(arr);
  return { data: keyMaterial };
}

// Generate a 3DES ECB key from the existing data in callback mode.
function test3DesEcb() {
  // Create a SymKeyGenerator instance.
  let symAlgName = '3DES192';
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName);
  if (symKeyGenerator == null) {
    console.error('createSymKeyGenerator failed');
    return;
  }
  console.info(`symKeyGenerator algName: ${symKeyGenerator.algName}`);

  // Create a Cipher instance.
  let cipherAlgName = '3DES192|ECB|PKCS7';
  let globalCipher = cryptoFramework.createCipher(cipherAlgName);

  // Generate a symmetric key based on the specified data.
  let keyMaterialBlob = genKeyMaterialBlob();
  try {
    symKeyGenerator.convertKey(keyMaterialBlob, (error, key) => {
      if (error) {
        console.error(`convertKey error, ${error.code}, ${error.message}`);
        return;
      }
      console.info(`key algName: ${key.algName}`);
      console.info(`key format: ${key.format}`);
      let encodedKey = key.getEncoded();
      console.info('key getEncoded: ' + encodedKey.data);
      let globalKey = key;

      // Initialize the Cipher instance and start encryption.
      let mode = cryptoFramework.CryptoMode.ENCRYPT_MODE;
      // init
      globalCipher.init(mode, key, null, (err,) => {
        let plainText: cryptoFramework.DataBlob = { data: stringToUint8Array('this is test!') };
        // update
        globalCipher.update(plainText, (err, updateOutput) => {
          let globalCipherText = updateOutput;
          //doFinal
          globalCipher.doFinal(null, (err, finalOutput) => {
            if (err) {
              console.error(`doFinal error, ${err.code}, ${err.message}`);
              return;
            }
            if (finalOutput != null) {
              let tmpCipherText = Array.from(globalCipherText.data);
              let tmpFinalOutput = Array.from(finalOutput.data);
              tmpCipherText = tmpCipherText.concat(tmpFinalOutput);
              globalCipherText = { data: new Uint8Array(tmpCipherText) };
            }
            // Initialize the Cipher instance and start decryption.
            let mode = cryptoFramework.CryptoMode.DECRYPT_MODE;
            // init
            globalCipher.init(mode, globalKey, null, (err,) => {
              // update
              globalCipher.update(globalCipherText, (err, updateOutput) => {
                console.info('decrypt plainText: ' + uint8ArrayToString(updateOutput.data));
                // doFinal
                globalCipher.doFinal(null, (error, finalOutput) => {
                  if (finalOutput != null) { // Check whether the result is null before using finalOutput.data.
                    console.info('decrypt plainText: ' + uint8ArrayToString(finalOutput.data));
                  }
                })
              })
            })
          })
        })
      })
    })
  } catch (error) {
    let e: BusinessError = error as BusinessError;
    console.error(`3des failed, ${e.code}, ${e.message}`);
    return;
  }
}

Encrypting and Decrypting Data Using an AES GCM Symmetric Key by Segment (Promise)

Use an AES symmetric key to encrypt and decrypt a large amount of data by segment using update().

1. Create a SymKeyGenerator instance.
2. Generate a key based on the existing binary data.
3. Create a Cipher instance.
4. Encrypt or decrypt data.

Example: Encrypt and decrypt a large amount in AES GCM mode by calling update() multiple times in promise mode.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function genGcmParamsSpec() {
  let arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; // 12 bytes
  let dataIv = new Uint8Array(arr);
  let ivBlob: cryptoFramework.DataBlob = { data: dataIv };

  arr = [0, 0, 0, 0, 0, 0, 0, 0]; // 8 bytes
  let dataAad = new Uint8Array(arr);
  let aadBlob: cryptoFramework.DataBlob = { data: dataAad };

  arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]; // 16 bytes
  let dataTag = new Uint8Array(arr);
  let tagBlob: cryptoFramework.DataBlob = {
    data: dataTag
  }; // The GCM authTag is obtained by doFinal() in encryption and passed in params of init() in decryption.

  let gcmParamsSpec: cryptoFramework.GcmParamsSpec = {
    iv: ivBlob,
    aad: aadBlob,
    authTag: tagBlob,
    algName: "GcmParamsSpec"
  };
  return gcmParamsSpec;
}

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

function testAesMultiUpdate() {
  let symAlgName = 'AES128';
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName);
  console.info(`symKeyGenerator algName: ${symKeyGenerator.algName}`);
  // Generate GCM parameter specifications.
  let globalGcmParams = genGcmParamsSpec();
  // Create a Cipher instance.
  let cipherAlgName = 'AES128|GCM|PKCS7';
  let globalCipher = cryptoFramework.createCipher(cipherAlgName);
  console.info(`cipher algName: ${globalCipher.algName}`);
  // Use the key generator to randomly generate a 128-bit symmetric key.
  let globalCipherText: cryptoFramework.DataBlob;
  let globalKey: cryptoFramework.SymKey;
  let globalPlainText = '';
  let promiseSymKey = symKeyGenerator.generateSymKey();
  promiseSymKey.then(key => {
    // Initialize the Cipher instance and start encryption.
    globalKey = key;
    let mode = cryptoFramework.CryptoMode.ENCRYPT_MODE;
    return globalCipher.init(mode, globalKey, globalGcmParams);
  })
    .then(async () => {
      let plainText = "aaaaa.....bbbbb.....ccccc.....ddddd.....eee"; // Assume that the plaintext is of 43 bytes.
      let messageArr: number[] = [];
      let updateLength = 20; // Pass in 20 bytes by update() each time.
      let tmpCipherText = new Uint8Array();

      for (let i = 0; i <= plainText.length; i++) {
        if ((i % updateLength == 0||i == plainText.length) && messageArr.length != 0) {
          let message = new Uint8Array(messageArr);
          let messageBlob: cryptoFramework.DataBlob = { data: message };
          let updateOutput = await globalCipher.update(messageBlob); // Update by segment.
          // Combine the result of each update() to obtain the ciphertext. In certain cases, the doFinal() results need to be combined, which depends on the cipher block mode
          // and padding mode you use. In this example, the doFinal() result in GCM mode contains authTag but not ciphertext. Therefore, there is no need to combine the results.
          let mergeText = new Uint8Array(tmpCipherText.length + updateOutput.data.length);
          mergeText.set(tmpCipherText);
          mergeText.set(updateOutput.data, tmpCipherText.length);
          tmpCipherText = mergeText;
          // tmpCipherText = tmpCipherText.concat(Array.from(updateOutput.data));
          messageArr = [];
        }
        if (i < plainText.length) {
          messageArr.push(plainText.charCodeAt(i));
        }
      }
      globalCipherText = { data: tmpCipherText };
      return;
    })
    .then((): Promise<cryptoFramework.DataBlob> => {
      return globalCipher.doFinal(null);
    })
    .then(tag => {
      // In GCM mode, the encrypted authentication information needs to be obtained from the output of doFinal() and passed in globalGcmParams of init() in decryption.
      globalGcmParams.authTag = tag;
      return;
    })
    .then(() => {
      // Initialize the Cipher instance and start decryption.
      let mode = cryptoFramework.CryptoMode.DECRYPT_MODE;
      return globalCipher.init(mode, globalKey, globalGcmParams);
    })
    .then(async () => {
      let updateLength = 20;
      let updateTimes = Math.ceil(globalCipherText.data.length / updateLength); // Round up to the nearest integer.
      for (let i = 0; i < updateTimes; i++) {
        let messageArr = globalCipherText.data.slice(i * updateLength, (i + 1) * updateLength);
        let message = new Uint8Array(messageArr);
        let messageBlob: cryptoFramework.DataBlob = { data: message };
        let updateOutput = await globalCipher.update(messageBlob); // Update by segment.
        globalPlainText += uint8ArrayToString(updateOutput.data); // Restore the original plaintext.
      }
      return;
    })
    .then((): Promise<cryptoFramework.DataBlob> => {
      return globalCipher.doFinal(null);
    })
    .then(finalOutput => {
      if (finalOutput == null) { // Check whether the result is null before using finalOutput.data.
        console.info('GCM finalOutput is null');
      }
      console.info(`decrypt output: ${globalPlainText}`);
    })
    .catch((error: BusinessError) => {
      console.error(`catch error, ${error.code}, ${error.message}`);
    })
}

Encrypting and Decrypting Data Using RSA

Encrypt and decrypt data using an RSA asymmetric key pair.

1. Generate an RSA key pair.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an RSA asymmetric key pair.
2. Create a Cipher instance.
   Call createCipher() to create a Cipher instance, and set the key and encryption/decryption mode.
3. Encrypt and decrypt data.
   Call doFinal() provided by the Cipher instance to encrypt data or decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

let plan = "This is cipher test.";

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Encrypt the message in promise mode.
function encryptMessagePromise() {
  // Create an AsyKeyGenerator instance.
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  // Create a Cipher instance.
  let cipher = cryptoFramework.createCipher("RSA1024|PKCS1");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  let keyGenPromise = rsaGenerator.generateKeyPair();
  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    let pubKey = rsaKeyPair.pubKey;
    // Initialize the Cipher instance and use the public key to encrypt the data.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, pubKey, null);
  }).then(() => {
    // doFinal
    let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
    return cipher.doFinal(input);
  }).then(dataBlob => {
    // Obtain the encrypted data.
    console.info("EncryptOutPut is " + dataBlob.data);
  });
}

// Encrypt the message in callback mode.
function encryptMessageCallback() {
  // Create an AsyKeyGenerator instance.
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  // Create a Cipher instance.
  let cipher = cryptoFramework.createCipher("RSA1024|PKCS1");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  rsaGenerator.generateKeyPair((err, keyPair) => {
    let pubKey = keyPair.pubKey;
    // Initialize the Cipher instance and use the public key to encrypt the data.
    cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, pubKey, null, (err, data) => {
      let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
      // doFinal
      cipher.doFinal(input, (err, data) => {
        // Obtain the encrypted data.
        console.info("EncryptOutPut is " + data.data);
      })
    })
  })
}

// Encrypt and decrypt the message in promise mode.
function decryptMessagePromise() {
  // Create an AsyKeyGenerator instance.
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  // Create a Cipher instance for encryption.
  let cipher = cryptoFramework.createCipher("RSA1024|PKCS1");
  // Create a Cipher instance for decryption.
  let decoder = cryptoFramework.createCipher("RSA1024|PKCS1");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  let keyGenPromise = rsaGenerator.generateKeyPair();
  let keyPair: cryptoFramework.KeyPair;
  let cipherDataBlob: cryptoFramework.DataBlob;
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    keyPair = rsaKeyPair;
    // Initialize the Cipher instance and use the public key to encrypt the message.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null);
  })
    .then(() => {
      // Call doFinal() to encrypt data.
      return cipher.doFinal(input);
    })
    .then((dataBlob: cryptoFramework.DataBlob): Promise<void> => {
      // Obtain the encrypted information and use it as the input parameter for decryption.
      console.info("EncryptOutPut is " + dataBlob.data);
      AlertDialog.show({ message: "output" + dataBlob.data });
      cipherDataBlob = dataBlob;
      // Initialize the Cipher instance and use the private key to decrypt the message.
      return decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null);
    })
    .then(() => {
      // Call doFinal() to decrypt the data.
      return decoder.doFinal(cipherDataBlob);
    })
    .then(decodeData => {
      // Check whether the decrypted data is consistent with the original data.
      if (decodeData.data.toString() === input.data.toString()) {
        AlertDialog.show({ message: "decrypt success" });
        return;
      }
      AlertDialog.show({ message: "decrypt fail" });
    });
}

// Encrypt and decrypt the message in callback mode.
function decryptMessageCallback() {
  // Create an AsyKeyGenerator instance.
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  // Create a Cipher instance for encryption.
  let cipher = cryptoFramework.createCipher("RSA1024|PKCS1");
  // Create a Cipher instance for decryption.
  let decoder = cryptoFramework.createCipher("RSA1024|PKCS1");
  let plainText = "this is cipher text";
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plainText) };
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  rsaGenerator.generateKeyPair((err, newKeyPair) => {
    let keyPair = newKeyPair;
    // Initialize the Cipher instance and use the public key to encrypt the message.
    cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null, (err, data) => {
      // Call doFinal() to encrypt the message.
      cipher.doFinal(input, (err, data) => {
        // Obtain the encrypted information and use it as the input parameter for decryption.
        AlertDialog.show({ message: "EncryptOutPut is " + data.data });
        let cipherData = data;
        // Initialize the Cipher instance and use the private key to decrypt the message.
        decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null, (err, data) => {
          // Call doFinal() to decrypt the message.
          decoder.doFinal(cipherData, (err, data) => {
            // Check whether the decrypted data is consistent with the original data.
            if (input.data.toString() === data.data.toString()) {
              AlertDialog.show({ message: "decryption success" });
              return;
            }
            AlertDialog.show({ message: "decryption fail" });
          });
        });
      });
    });
  });
}

Encrypting and Decrypting Data Using RSA by Segment

Use an RSA asymmetric key pair to encrypt and decrypt a large amount of data by segment.

1. Generate an RSA key pair.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an RSA asymmetric key pair.
2. Create a Cipher instance.
   Call createCipher() to create a Cipher instance, and set the key and encryption/decryption mode.
3. Encrypt and decrypt data.
   Call doFinal() provided by the Cipher instance multiple times to encrypt and decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

function encryptLongMessagePromise() {
  let globalPlainText = "This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!";
  let globalKeyPair: cryptoFramework.KeyPair;
  let plainTextSplitLen = 64; // The length of the plaintext to be encrypted or decrypted each time by RSA depends on the number of key bits and padding mode. For details, see the Crypto Framework Overview.
  let cipherTextSplitLen = 128; // Length of the ciphertext = Number of key bits/8
  let keyGenName = "RSA1024";
  let cipherAlgName = "RSA1024|PKCS1";
  let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator(keyGenName); // Create an AsyKeyGenerator object.
  let cipher = cryptoFramework.createCipher(cipherAlgName); // Create a Cipher object.
  let decoder = cryptoFramework.createCipher(cipherAlgName); // Create a Decoder object.
  let keyGenPromise = asyKeyGenerator.generateKeyPair(); // Generate an RSA key pair.
  let globalCipherText: cryptoFramework.DataBlob;

  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    globalKeyPair = rsaKeyPair; // Save the key pair as a global variable.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, globalKeyPair.pubKey, null);
  })
    .then(async () => {
      let tmpCipherText = new Uint8Array();
      // Split the plaintext by 64 characters and cyclically call doFinal() to encrypt the plaintext. If a 1024-bit key is used, 128-byte ciphertext is generated each time.
      for (let i = 0; i < (globalPlainText.length / plainTextSplitLen); i++) {
        let tempStr = globalPlainText.substr(i * plainTextSplitLen, plainTextSplitLen);
        let tempBlob: cryptoFramework.DataBlob = { data: stringToUint8Array(tempStr) };
        let tempCipherOutput = await cipher.doFinal(tempBlob);
        let mergeText = new Uint8Array(tmpCipherText.length + tempCipherOutput.data.length);
        mergeText.set(tmpCipherText);
        mergeText.set(tempCipherOutput.data, tmpCipherText.length);
        tmpCipherText = mergeText;
      }
      globalCipherText = { data: tmpCipherText };
      console.info(`globalCipherOutput len is ${tmpCipherText.length}, data is: ${tmpCipherText.toString()}`);
      return;
    })
    .then((): Promise<void> => {
      return decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, globalKeyPair.priKey, null);
    })
    .then(async () => {
      let tmpDecodeText = new Uint8Array();
      // Split and decrypt the ciphertext by 128 bytes, and combine the plaintext obtained each time.
      for (let i = 0; i < (globalCipherText.data.length / cipherTextSplitLen); i++) {
        let tempBlobData = globalCipherText.data.slice(i * cipherTextSplitLen, (i + 1) * cipherTextSplitLen);
        let message = new Uint8Array(tempBlobData);
        let tempBlob: cryptoFramework.DataBlob = { data: message };
        let tempDecodeOutput = await decoder.doFinal(tempBlob);
        let mergeText = new Uint8Array(tmpDecodeText.length + tempDecodeOutput.data.length);
        mergeText.set(tmpDecodeText);
        mergeText.set(tempDecodeOutput.data, tmpDecodeText.length);
        tmpDecodeText = mergeText;
      }
      let globalDecodeOutput = uint8ArrayToString(tmpDecodeText);
      if (globalDecodeOutput === globalPlainText) {
        console.info(`encode and decode success`);
      } else {
        console.info(`encode and decode error`);
      }
      return;
    })
    .catch((error: BusinessError) => {
      console.error(`catch error, ${error.code}, ${error.message}`);
    })
}

NOTE

• In RSA encryption and decryption, init() cannot be repeatedly called to initialize a Cipher instance. You must create a Cipher instance for each encryption and decryption.
• The RSA encryption has a limit on the length of the plaintext to be encrypted. For details, see Encryption and Decryption.
• In RSA decryption, the length of the ciphertext to be decrypted each time is the number of bits of the RSA key divided by 8.

Using PKCS1_OAEP in RSA Encryption and Decryption

Use the PKCS1_OAEP padding mode in RSA encryption and decryption in promise mode.

1. Generate an RSA key pair based on the key parameters.
   Call createAsyKeyGeneratorBySpec() to create an AsyKeyGeneratorBySpec object and generate an RSA asymmetric key pair. (You can also use createAsyKeyGenerator() to randomly generate or convert an RSA key object.)
2. Create a Cipher instance.
   Call createCipher() to create a cipher instance, initialize the cipher instance, set the key and encryption/decryption mode, use setCipherSpec() to set PKCS1_OAEP pSource, and use update() to pass in data.
3. Encrypt and decrypt data.
   Call the doFinal() API provided by the Cipher class to perform encryption or decryption. The pSource of the Cipher instance to be encrypted must be the same as that decrypted.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Construct the key parameters of the RSA asymmetric key pair based on the key pair specifications.
function genRsaKeyPairSpec(nIn: bigint, eIn: bigint, dIn: bigint) {
  let rsaCommSpec: cryptoFramework.RSACommonParamsSpec = {
    n: nIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.COMMON_PARAMS_SPEC
  };
  let rsaKeyPairSpec: cryptoFramework.RSAKeyPairSpec = {
    params: rsaCommSpec,
    sk: dIn,
    pk: eIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.KEY_PAIR_SPEC
  };
  return rsaKeyPairSpec;
}

// Generate RSA2048 key pair parameters.
function genRsa2048KeyPairSpec(): cryptoFramework.RSAKeyPairSpec {
  let nIn = BigInt("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");
  let eIn = BigInt("0x010001");
  let dIn = BigInt("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");
  return genRsaKeyPairSpec(nIn, eIn, dIn);
}

function rsaUseSpecDecryptOAEPPromise() {
  let plan = "This is cipher test.";
  // Obtain the key parameter object of the RSA key pair.
  let rsaKeyPairSpec = genRsa2048KeyPairSpec();
  // Generate an RSA key pair based on the RSA key parameters.
  let rsaGeneratorSpec = cryptoFramework.createAsyKeyGeneratorBySpec(rsaKeyPairSpec);
  let keyGenPromise = rsaGeneratorSpec.generateKeyPair();
  let cipher = cryptoFramework.createCipher("RSA|PKCS1_OAEP|SHA256|MGF1_SHA1");
  let decoder = cryptoFramework.createCipher("RSA|PKCS1_OAEP|SHA256|MGF1_SHA1");
  let keyPair: cryptoFramework.KeyPair;
  let cipherDataBlob: cryptoFramework.DataBlob;
  // Set the pSource, which defines the encoding input P filled by OAEP.
  let pSource = new Uint8Array([1, 2, 3, 4]);
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
  // Generate the key pair.
  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    keyPair = rsaKeyPair;
    // Initialize the Cipher instance for encryption.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null);
  })
    .then(() => {
      // Set and obtain the cipher specifications after the initialization.
      cipher.setCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_PSRC_UINT8ARR, pSource);
      let retP = cipher.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_PSRC_UINT8ARR);
      // Check whether the obtained PSource is the same as the PSource set.
      if (retP.toString() != pSource.toString()) {
        AlertDialog.show({ message: "error init pSource" + retP });
      } else {
        console.info("pSource changed ==" + retP);
      }
      // Obtain other OAEP parameters.
      let md = cipher.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MD_NAME_STR);
      console.info("md == " + md);
      let mgf = cipher.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF_NAME_STR);
      console.info("mgf == " + mgf);
      let mgf1Md = cipher.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_MD_STR);
      console.info("mgf1Md == " + mgf1Md);
      return cipher.doFinal(input);
    })
    .then((dataBlob: cryptoFramework.DataBlob): Promise<void> => {
      console.info("EncryptOutPut is " + dataBlob.data);
      cipherDataBlob = dataBlob;
      // The get() and set() operations can be performed before the init() operation of the Cipher object and are equivalent to those after the init() operation. For example, set and get the decoder.
      decoder.setCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_PSRC_UINT8ARR, pSource);
      let retP = decoder.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_PSRC_UINT8ARR);
      // Check whether the obtained PSource is the same as the PSource set.
      if (retP.toString() != pSource.toString()) {
        AlertDialog.show({ message: "error init pSource" + retP });
      } else {
        console.info("pSource changed ==" + retP);
      }
      // Obtain other OAEP parameters.
      let md = decoder.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MD_NAME_STR);
      console.info("md == " + md);
      let mgf = decoder.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF_NAME_STR);
      console.info("mgf == " + mgf);
      let mgf1Md = decoder.getCipherSpec(cryptoFramework.CipherSpecItem.OAEP_MGF1_MD_STR);
      console.info("mgf1Md == " + mgf1Md);
      // Initialize the decryption operation.
      return decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null);
    })
    .then(() => {
      return decoder.doFinal(cipherDataBlob);
    })
    .then(decodeData => {
      // The decryption is successful.
      if (decodeData.data.toString() === input.data.toString()) {
        console.info("oaep decrypt success");
        AlertDialog.show({ message: " oaep decrypt success" });
      } else {
        AlertDialog.show({ message: "oeap decrypt fail" });
      }
    });
}

Encrypting and Decrypting Data Using SM2

NOTE

SM2 encryption and decryption are supported from API version 10.

Use an SM2 asymmetric key pair to encrypt and decrypt data.

1. Generate an SM2 key pair. Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an SM2 asymmetric key pair.
2. Create a Cipher instance.
   Call createCipher() to create a Cipher instance, and set the key and encryption/decryption mode.
3. Encrypt and decrypt data.
   Call doFinal() provided by the Cipher instance to encrypt data or decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

let plan = "This is cipher test.";

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Encrypt the message in promise mode.
function encryptMessagePromise() {
  // Create an AsyKeyGenerator instance.
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  // Create a Cipher instance.
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  let keyGenPromise = sm2Generator.generateKeyPair();
  keyGenPromise.then((sm2KeyPair: cryptoFramework.KeyPair): Promise<void> => {
    let pubKey = sm2KeyPair.pubKey;
    // Initialize the Cipher instance and use the public key to encrypt the message.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, pubKey, null);
  }).then(() => {
    // doFinal
    let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
    return cipher.doFinal(input);
  }).then(dataBlob => {
    // Obtain the encrypted data.
    console.info("EncryptOutPut is " + dataBlob.data);
  });
}

// Encrypt the message in callback mode.
function encryptMessageCallback() {
  // Create an AsyKeyGenerator instance.
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  // Create a Cipher instance.
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  sm2Generator.generateKeyPair((err, keyPair) => {
    let pubKey = keyPair.pubKey;
    // Initialize the Cipher instance and use the public key to encrypt the message.
    cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, pubKey, null, (err, data) => {
      let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
      // doFinal
      cipher.doFinal(input, (err, data) => {
        // Obtain the encrypted data.
        console.info("EncryptOutPut is " + data.data);
      })
    })
  })
}

// Encrypt and decrypt data in promise mode.
function decryptMessagePromise() {
  // Create an AsyKeyGenerator instance.
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  // Create a Cipher instance for encryption.
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  // Create a Cipher instance for decryption.
  let decoder = cryptoFramework.createCipher("SM2_256|SM3");
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  let keyGenPromise = sm2Generator.generateKeyPair();
  let keyPair: cryptoFramework.KeyPair;
  let cipherDataBlob: cryptoFramework.DataBlob;
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plan) };
  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    keyPair = rsaKeyPair;
    // Initialize the Cipher instance and use the public key to encrypt the data.
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null);
  })
    .then(() => {
      // Call doFinal() to encrypt data.
      return cipher.doFinal(input);
    })
    .then((dataBlob: cryptoFramework.DataBlob): Promise<void> => {
      // Obtain the encrypted information and use it as the input parameter for decryption.
      console.info("EncryptOutPut is " + dataBlob.data);
      AlertDialog.show({ message: "output" + dataBlob.data });
      cipherDataBlob = dataBlob;
      // Initialize the Cipher instance and use the private key to decrypt the data.
      return decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null);
    })
    .then(() => {
      // Call doFinal() to decrypt data.
      return decoder.doFinal(cipherDataBlob);
    })
    .then(decodeData => {
      // Check whether the decrypted data is consistent with the original data.
      if (decodeData.data.toString() === input.data.toString()) {
        AlertDialog.show({ message: "decrypt success" });
        return;
      }
      AlertDialog.show({ message: "decrypt fail" });
    });
}

// Encrypt and decrypt data in callback mode.
function decryptMessageCallback() {
  // Create an AsyKeyGenerator instance.
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  // Create a Cipher instance for encryption.
  let cipher = cryptoFramework.createCipher("SM2_256|SM3");
  // Create a Cipher instance for decryption.
  let decoder = cryptoFramework.createCipher("SM2_256|SM3");
  let plainText = "this is cipher text";
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plainText) };
  let cipherData: cryptoFramework.DataBlob;
  let keyPair: cryptoFramework.KeyPair;
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  sm2Generator.generateKeyPair((err, newKeyPair) => {
    keyPair = newKeyPair;
    // Initialize the Cipher instance and use the public key to encrypt the data.
    cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, keyPair.pubKey, null, (err, data) => {
      // Call doFinal() to encrypt data.
      cipher.doFinal(input, (err, data) => {
        // Obtain the encrypted information and use it as the input parameter for decryption.
        AlertDialog.show({ message: "EncryptOutPut is " + data.data });
        cipherData = data;
        // Initialize the Cipher instance and use the private key to decrypt the data.
        decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, keyPair.priKey, null, (err, data) => {
          // Call doFinal() to decrypt data.
          decoder.doFinal(cipherData, (err, data) => {
            // Check whether the decrypted data is consistent with the original data.
            if (input.data.toString() === data.data.toString()) {
              AlertDialog.show({ message: "decrypt success" });
              return;
            }
            AlertDialog.show({ message: "decrypt fail" });
          });
        });
      });
    });
  });
}

Encrypting and Decrypting Data Using an SM4 ECB Symmetric Key (Callback)

NOTE

SM4 encryption and decryption are supported from API version 10.

Use an SM4 symmetric key to encrypt and decrypt data.

1. Create a SymKeyGenerator instance.
2. Generate a key based on the existing binary data.
3. Create a Cipher instance.
4. Encrypt or decrypt data.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

// Use SM4 ECB to encrypt and decrypt a message in callback mode.
function testSM4Ecb() {
  // Create an AsyKeyGenerator instance.
  let sm4Generator = cryptoFramework.createSymKeyGenerator('SM4_128');
  // Create a Cipher instance for encryption.
  let cipher = cryptoFramework.createCipher("SM4_128|ECB|PKCS7");
  // Create a Cipher instance for decryption.
  let decoder = cryptoFramework.createCipher("SM4_128|ECB|PKCS7");
  let plainText = "this is cipher text";
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plainText) };
  let cipherData: cryptoFramework.DataBlob;
  let key: cryptoFramework.SymKey;
  // Generate an asymmetric key pair using the AsyKeyGenerator instance.
  sm4Generator.generateSymKey((err, newKey) => {
    key = newKey;
    // Initialize the Cipher instance and use the public key to encrypt the data.
    cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, key, null, (err, data) => {
      // Call doFinal() to encrypt data.
      cipher.doFinal(input, (err, data) => {
        // Obtain the encrypted information and use it as the input parameter for decryption.
        AlertDialog.show({ message: "EncryptOutPut is " + data.data });
        cipherData = data;
        // Initialize the Cipher instance and use the private key to decrypt the data.
        decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, key, null, (err, data) => {
          // Call doFinal() to decrypt data.
          decoder.doFinal(cipherData, (err, data) => {
            // Check whether the decrypted data is consistent with the original data.
            if (input.data.toString() === data.data.toString()) {
              AlertDialog.show({ message: "decrypt success" });
              return;
            }
            AlertDialog.show({ message: "decrypt fail" });
          });
        });
      });
    });
  });
}

Signing and Signature Verification

When to Use

A digital signature can be used to verify the authenticity of a message. Typical signing and signature verification operations involve the following: 1. Use RSA to generate a signature and verify the signature. 2. Use ECC to generate a signature and verify the signature. 3. Use RSA to generate a signature and verify the signature. Obtain and set SignSpecItem when the PSS padding mode is used. 4. Use SM2 to generate a signature and verify the signature.

NOTE

• From API version 10, SignSpecItem can be set and obtained when the PSS padding mode is used.
• From API version 10, the string parameter without the key length is supported in signature verification.

Available APIs

The following table describes the APIs used in typical signing and signature verification operations. For more information about the APIs, see Crypto Framework. > NOTE > > Due to complexity of cryptographic algorithms, the implementation varies depending on the specifications and parameters you use, and cannot be enumerated by sample code. Before you start, understand the APIs to ensure correct use of these APIs.

Signing and Signature Verification Using RSA

Use RSA to sign data and verify the signature.

1. Generate an RSA key pair.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an RSA asymmetric key pair.
2. Create a Sign instance.
   Call createSign() to create a Sign instance, initialize the Sign instance, and set a private key for signing.
3. Generate a signature.
   Call update() provided by the Sign class to pass in the data for signing and call sign() to generate a signature.
4. Create a Verify instance.
   Call createVerify() to create a Verify instance, initialize the instance, and set a public key for signature verification.
5. Verify the signature.
   Call update() provided by the Verify class to pass in the signature data and call verify() to verify the signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

let globalKeyPair: cryptoFramework.KeyPair;
let signMessageBlob: cryptoFramework.DataBlob;
let plan1 = "This is Sign test plan1";
let plan2 = "This is Sign test plan1";
let input1: cryptoFramework.DataBlob = { data: stringToUint8Array(plan1) };
let input2: cryptoFramework.DataBlob = { data: stringToUint8Array(plan2) };

function signMessagePromise() {
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  let signer = cryptoFramework.createSign("RSA1024|PKCS1|SHA256"); // From API version 10, a Sign instance can be created by specifying a string parameter defining the key specifications.
  let keyGenPromise = rsaGenerator.generateKeyPair();
  keyGenPromise.then(keyPair => {
    globalKeyPair = keyPair;
    let priKey = globalKeyPair.priKey;
    return signer.init(priKey);
  }).then(() => {
    return signer.update(input1);
  }).then(() => {
    return signer.sign(input2);
  }).then(dataBlob => {
    signMessageBlob = dataBlob;
    console.info("sign output is " + signMessageBlob.data);
  });
}

// Call verify() after sign() is called.
function verifyMessagePromise() {
  let verifyer = cryptoFramework.createVerify("RSA1024|PKCS1|SHA256");
  let verifyInitPromise = verifyer.init(globalKeyPair.pubKey);
  verifyInitPromise.then(() => {
    return verifyer.update(input1);
  }).then(() => {
    return verifyer.verify(input2, signMessageBlob);
  }).then(res => {
    console.log("Verify result is " + res);
  });
}

function signMessageCallback() {
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator("RSA1024|PRIMES_2");
  let signer = cryptoFramework.createSign("RSA1024|PKCS1|SHA256"); // From API version 10, a Sign instance can be created by specifying a string parameter defining the key specifications.
  rsaGenerator.generateKeyPair((err, keyPair) => {
    globalKeyPair = keyPair;
    let priKey = globalKeyPair.priKey;
    signer.init(priKey, err => {
      signer.update(input1, err => {
        signer.sign(input2, (err, data) => {
          signMessageBlob = data;
          console.info("sign output is " + signMessageBlob.data);
        });
      });
    });
  });
}

// Call verify() after sign() is called.
function verifyMessageCallback() {
  let verifyer = cryptoFramework.createVerify("RSA1024|PKCS1|SHA256");
  verifyer.init(globalKeyPair.pubKey, err => {
    verifyer.update(input1, err => {
      verifyer.verify(input2, signMessageBlob, (err, data) => {
        console.info("verify result is " + data);
      });
    });
  })
}

Signing and Signature Verification Using ECDSA

Use ECDSA to sign data and verify the signature.

1. Generate an ECC key.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an ECC asymmetric key pair.
2. Create a Sign instance.
   Call createSign() to create a Sign instance, initialize the Sign instance, and set a private key for signing.
3. Generate a signature.
   Call update() provided by the Sign class to pass in the data for signing and call doFinal() to generate a signature.
4. Create a Verify instance.
   Call createVerify() to create a Verify instance, initialize the instance, and set a public key for signature verification.
5. Verify the signature.
   Call update() provided by the Verify class to pass in the signature data and call doFinal() to verify the signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

let globalKeyPair: cryptoFramework.KeyPair;
let signMessageBlob: cryptoFramework.DataBlob;
let plan1 = "This is Sign test plan1";
let plan2 = "This is Sign test plan1";
let input1: cryptoFramework.DataBlob = { data: stringToUint8Array(plan1) };
let input2: cryptoFramework.DataBlob = { data: stringToUint8Array(plan2) };

function signMessagePromise() {
  let eccGenerator = cryptoFramework.createAsyKeyGenerator("ECC256");
  let signer = cryptoFramework.createSign("ECC256|SHA256");
  let keyGenPromise = eccGenerator.generateKeyPair();
  keyGenPromise.then(keyPair => {
    globalKeyPair = keyPair;
    let priKey = globalKeyPair.priKey;
    return signer.init(priKey);
  }).then(() => {
    return signer.update(input1);
  }).then(() => {
    return signer.sign(input2);
  }).then(dataBlob => {
    signMessageBlob = dataBlob;
    console.info("sign output is " + signMessageBlob.data);
  });
}

function verifyMessagePromise() {
  let verifyer = cryptoFramework.createVerify("ECC256|SHA256");
  let verifyInitPromise = verifyer.init(globalKeyPair.pubKey);
  verifyInitPromise.then(() => {
    return verifyer.update(input1);
  }).then(() => {
    return verifyer.verify(input2, signMessageBlob);
  }).then(res => {
    console.log("Verify result is " + res);
  });
}

function signMessageCallback() {
  let eccGenerator = cryptoFramework.createAsyKeyGenerator("ECC256");
  let signer = cryptoFramework.createSign("ECC256|SHA256");
  eccGenerator.generateKeyPair((err, keyPair) => {
    globalKeyPair = keyPair;
    let priKey = globalKeyPair.priKey;
    signer.init(priKey, err => {
      signer.update(input1, err => {
        signer.sign(input2, (err, data) => {
          signMessageBlob = data;
          console.info("sign output is " + signMessageBlob.data);
        });
      });
    });
  });
}

function verifyMessageCallback() {
  let verifyer = cryptoFramework.createVerify("ECC256|SHA256");
  verifyer.init(globalKeyPair.pubKey, err => {
    verifyer.update(input1, err => {
      verifyer.verify(input2, signMessageBlob, (err, data) => {
        console.info("verify result is " + data);
      });
    });
  })
}

Signing and Signature Verification Using RSA by Segment

Use RSA to sign data and verify the signature by segment.

1. Generate an RSA key pair.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an RSA asymmetric key pair.
2. Create a Sign instance.
   Call createSign() to create a Sign instance, initialize the Sign instance, and set a private key for signing.
3. Generate a signature.
   Call the update() provided by the Sign class multiple times to pass in data by segment and call sign() to generate a signature.
4. Create a Verify instance.
   Call createVerify() to create a Verify instance, initialize the instance, and set a public key for signature verification.
5. Verify the signature.
   Call the update() method provided by the Verify class multiple times to pass in data by segment and call verify() to verify the signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

function signLongMessagePromise() {
  let globalPlainText = "This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
    "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!";
  let globalSignData: Uint8Array;
  let textSplitLen = 64; // Customized data splitting length.
  let keyGenName = "RSA1024";
  let signAlgName = "RSA1024|PKCS1|SHA256";
  let globalKeyPair: cryptoFramework.KeyPair;
  let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator(keyGenName); // Create an AsyKeyGenerator object.
  let signer = cryptoFramework.createSign(signAlgName); // Create a Signer instance.
  let verifier = cryptoFramework.createVerify(signAlgName); // Create a Verifier instance.
  let keyGenPromise = asyKeyGenerator.generateKeyPair();
  keyGenPromise.then((rsaKeyPair: cryptoFramework.KeyPair): Promise<void> => {
    globalKeyPair = rsaKeyPair; // Save the key pair as a global variable.
    return signer.init(globalKeyPair.priKey);
  })
    .then(async (): Promise<void> => {
      // If the plaintext is too large, split the plaintext based on the specified length and cyclically call update() to pass in the plaintext.
      for (let i = 0; i < (globalPlainText.length / textSplitLen); i++) {
        let tempStr = globalPlainText.substr(i * textSplitLen, textSplitLen);
        let tempBlob: cryptoFramework.DataBlob = { data: stringToUint8Array(tempStr) };
        await signer.update(tempBlob);
      }
    })
    .then((): Promise<cryptoFramework.DataBlob> => {
      return signer.sign(null);
    })
    .then((signData: cryptoFramework.DataBlob): Promise<void> => {
      globalSignData = signData.data;
      console.info(`globalSignOutput len is ${globalSignData.length}, data is: ${globalSignData.toString()}`);
      return verifier.init(globalKeyPair.pubKey);
    })
    .then(async () => {
      // If the plaintext is too large, split the plaintext based on the specified length and cyclically call update() to pass in the plaintext.
      for (let i = 0; i < (globalPlainText.length / textSplitLen); i++) {
        let tempData = globalPlainText.slice(i * textSplitLen, (i + 1) * textSplitLen);
        let tempBlob: cryptoFramework.DataBlob = { data: stringToUint8Array(tempData) };
        await verifier.update(tempBlob);
      }
      return;
    })
    .then((): Promise<boolean> => {
      return verifier.verify(null, { data: globalSignData });
    })
    .then(res => {
      console.info(`verify res is ${res}`);
    })
    .catch((error: BusinessError) => {
      console.error(`catch error, ${error.code}, ${error.message}`);
    })
}

Using PSS in RSA Signing and Signature Verification

Use the PSS padding mode in RSA signing and signature verification in callback mode.

1. Generate an RSA key pair based on the key parameters.
   Call createAsyKeyGeneratorBySpec to create an AsyKeyGeneratorBySpec object and generate an RSA asymmetric key pair.
2. Create a Sign instance.
   Call createSign() to create a Sign object, initialize the Sign object, set the private key for signing, and set and obtain PSS parameters.
3. Generate a signature.
   Call update() provided by the Sign class to pass in the data for signing and call sign() to generate a signature.
4. Create a Verify instance.
   Call createVerify() to create a Verify object, initialize the object, set the public key for signature verification, and set and obtain PSS parameters. The signature verification is successful if the salt length is the same.
5. Verify the signature.
   Call update() provided by the Verify class to pass in the signature data and call verify() to verify the signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Convert byte streams into strings in plaintext.
function uint8ArrayToString(array: Uint8Array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

// Construct the key parameters of the RSA asymmetric key pair based on the key pair specifications.
function genRsaKeyPairSpec(nIn: bigint, eIn: bigint, dIn: bigint) {
  let rsaCommSpec: cryptoFramework.RSACommonParamsSpec = {
    n: nIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.COMMON_PARAMS_SPEC
  };
  let rsaKeyPairSpec: cryptoFramework.RSAKeyPairSpec = {
    params: rsaCommSpec,
    sk: dIn,
    pk: eIn,
    algName: "RSA",
    specType: cryptoFramework.AsyKeySpecType.KEY_PAIR_SPEC
  };
  return rsaKeyPairSpec;
}

// Generate RSA2048 key pair parameters.
function genRsa2048KeyPairSpec(): cryptoFramework.RSAKeyPairSpec {
  let nIn = BigInt("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");
  let eIn = BigInt("0x010001");
  let dIn = BigInt("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");
  return genRsaKeyPairSpec(nIn, eIn, dIn);
}

function verifyMessageCallbackPSS() {
  let plan1 = "This is Sign test plan1";
  let plan2 = "This is Sign test plan1";
  let input1: cryptoFramework.DataBlob = { data: stringToUint8Array(plan1) };
  let input2: cryptoFramework.DataBlob = { data: stringToUint8Array(plan2) };
  let globalKeyPair: cryptoFramework.KeyPair;
  let signMessageBlob: cryptoFramework.DataBlob;
  // Obtain the key parameter object of the RSA key pair.
  let rsaKeyPairSpec = genRsa2048KeyPairSpec();
  // Create an RSA key pair generator.
  let rsaGeneratorSpec = cryptoFramework.createAsyKeyGeneratorBySpec(rsaKeyPairSpec);
  // Both sign() and verify() support the RSA key with or without the length.
  let signer = cryptoFramework.createSign("RSA|PSS|SHA256|MGF1_SHA256");
  let verifyer = cryptoFramework.createVerify("RSA2048|PSS|SHA256|MGF1_SHA256");
  rsaGeneratorSpec.generateKeyPair((err, keyPair) => {
    globalKeyPair = keyPair;
    signer.init(globalKeyPair.priKey, err => {
      // After the initialization, set and obtain the PSS parameters.
      let setN = 32;
      signer.setSignSpec(cryptoFramework.SignSpecItem.PSS_SALT_LEN_NUM, setN);
      let saltLen = signer.getSignSpec(cryptoFramework.SignSpecItem.PSS_SALT_LEN_NUM);
      console.info("SaltLen == " + saltLen);
      let tf = signer.getSignSpec(cryptoFramework.SignSpecItem.PSS_TRAILER_FIELD_NUM);
      console.info("trailer field == " + tf);
      let md = signer.getSignSpec(cryptoFramework.SignSpecItem.PSS_MD_NAME_STR);
      console.info("md == " + md);
      let mgf = signer.getSignSpec(cryptoFramework.SignSpecItem.PSS_MGF_NAME_STR);
      console.info("mgf == " + mgf);
      let mgf1Md = signer.getSignSpec(cryptoFramework.SignSpecItem.PSS_MGF1_MD_STR);
      console.info("mgf1Md == " + mgf1Md);
      signer.update(input1, err => {
        signer.sign(input2, (err, data) => {
          // Before signature verification initialization, set and obtain PSS parameters. The functions are the same as those after initialization.
          signMessageBlob = data;
          AlertDialog.show({ message: "res" + signMessageBlob.data });
          let setN = 32;
          verifyer.setVerifySpec(cryptoFramework.SignSpecItem.PSS_SALT_LEN_NUM, setN);
          let saltLen = verifyer.getVerifySpec(cryptoFramework.SignSpecItem.PSS_SALT_LEN_NUM);
          console.info("SaltLen == " + saltLen);
          let tf = verifyer.getVerifySpec(cryptoFramework.SignSpecItem.PSS_TRAILER_FIELD_NUM);
          console.info("trailer field == " + tf);
          let md = verifyer.getVerifySpec(cryptoFramework.SignSpecItem.PSS_MD_NAME_STR);
          console.info("md == " + md);
          let mgf = verifyer.getVerifySpec(cryptoFramework.SignSpecItem.PSS_MGF_NAME_STR);
          console.info("mgf == " + mgf);
          let mgf1Md = verifyer.getVerifySpec(cryptoFramework.SignSpecItem.PSS_MGF1_MD_STR);
          console.info("mgf1Md == " + mgf1Md);
          verifyer.init(globalKeyPair.pubKey, err => {
            verifyer.update(input1, err => {
              verifyer.verify(input2, signMessageBlob, (err, data) => {
                AlertDialog.show({ message: "res " + data });
              })
            });
          });
        });
      });
    });
  });
}

Signing and Signature Verification Using SM2

NOTE

SM2 signing and signature verification are supported from API version 10.

Use SM2 to sign data and verify the signature.

1. Generate an SM2 key pair. Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an SM2 asymmetric key pair.
2. Create a Sign instance.
   Call createSign() to create a Sign instance, initialize the Sign instance, and set a private key for signing.
3. Generate a signature.
   Call update() provided by the Sign class to pass in the data for signing and call doFinal() to generate a signature.
4. Create a Verify instance.
   Call createVerify() to create a Verify instance, initialize the instance, and set a public key for signature verification.
5. Verify the signature.
   Call update() provided by the Verify class to pass in the signature data and call doFinal() to verify the signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

let plan1 = "This is Sign test plan1";
let plan2 = "This is Sign test plan2";
let input1: cryptoFramework.DataBlob = { data: stringToUint8Array(plan1) };
let input2: cryptoFramework.DataBlob = { data: stringToUint8Array(plan2) };

function signAndVerify() {
  let signMessageBlob: cryptoFramework.DataBlob;
  let sm2Generator = cryptoFramework.createAsyKeyGenerator("SM2_256");
  let signer = cryptoFramework.createSign("SM2_256|SM3");
  sm2Generator.generateKeyPair((err, keyPair) => {
    let priKey = keyPair.priKey;
    signer.init(priKey, err => {
      signer.update(input1, err => {
        signer.sign(input2, (err, data) => {
          signMessageBlob = data;
          console.info("sign output is " + signMessageBlob.data);
          let verifyer = cryptoFramework.createVerify("SM2_256|SM3");
          verifyer.init(keyPair.pubKey, err => {
            verifyer.update(input1, err => {
              verifyer.verify(input2, signMessageBlob, (err, data) => {
                console.info("verify result is " + data);
                AlertDialog.show({ message: "verify success" })
              });
            });
          })
        });
      });
    });
  });
}

Key Agreement

When to Use

Key agreement allows two parties to establish a shared secret over an insecure channel.

NOTE

From API version 10, the string parameter without the key length is supported in key agreement.

Available APIs

For details about the APIs, see Crypto Framework.

How to Develop

1. Generate an ECC key.
   Call createAsyKeyGenerator() to create an AsyKeyGenerator instance and generate an ECC asymmetric key pair.
2. Generate a shared secret by using the private and public ECC keys.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

let globalKeyPair: cryptoFramework.KeyPair;

function ecdhPromise() {
  let eccGenerator = cryptoFramework.createAsyKeyGenerator("ECC256");
  let eccKeyAgreement = cryptoFramework.createKeyAgreement("ECC256"); // ECC is supported for key agreement from API version 10.
  let keyGenPromise = eccGenerator.generateKeyPair();
  keyGenPromise.then(keyPair => {
    globalKeyPair = keyPair;
    return eccKeyAgreement.generateSecret(keyPair.priKey, keyPair.pubKey);
  }).then((secret) => {
    console.info("ecdh output is " + secret.data);
  }).catch((error: BusinessError) => {
    console.error("ecdh error.");
  });
}

function ecdhCallback() {
  let eccGenerator = cryptoFramework.createAsyKeyGenerator("ECC256");
  let eccKeyAgreement = cryptoFramework.createKeyAgreement("ECC256");
  eccGenerator.generateKeyPair((err, keyPair) => {
    globalKeyPair = keyPair;
    eccKeyAgreement.generateSecret(keyPair.priKey, keyPair.pubKey, (err, secret) => {
      if (err) {
        console.error("ecdh error.");
        return;
      }
      console.info("ecdh output is " + secret.data);
    });
  });
}

Message Digest

When to Use

A message digest (MD) is a fixed size numeric representation of the content of a message, computed by a hash function. It is sent with the message. The receiver can generate a digest for the message and compare it with the digest received. If the two digests are the same, the message integrity is verified.

Typical MD operations involve the following:

1. Create an Md instance with the specified digest algorithm (such as SHA-256).
2. Pass in one or more messages for generating a digest, and generate a digest.
3. Obtain the digest algorithm and digest length (in bytes).

Available APIs

For more information about the APIs, see Crypto Framework.

Generating a Digest

1. Use createMd() to create an Md instance.
2. Use update() to pass in data. update() can be called multiple times. The algorithm library does not limit the data length of a single update().
3. Use digest() to compute a digest.
4. Obtain the digest algorithm and length of the digest generated.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Generate a digest in promise mode.
function doMdByPromise() {
  let mdAlgName = "SHA256"; // Digest algorithm name.
  let message = "mdTestMessgae"; // Data to be digested.
  let md = cryptoFramework.createMd(mdAlgName);
  ;
  console.info("[Promise]: Md algName is: " + md.algName);
  // If the data volume is small, you can use update() once to pass in all data. There is no limit on the length of the input parameter.
  let promiseMdUpdate = md.update({ data: stringToUint8Array(message) });
  promiseMdUpdate.then(() => {
    // Call digest() to return the result.
    let PromiseMdDigest = md.digest();
    return PromiseMdDigest;
  }).then(digestOutput => {
    let mdOutput = digestOutput;
    console.info("[Promise]: MD result: " + mdOutput.data);
    let mdLen = md.getMdLength();
    console.info("[Promise]: MD len: " + mdLen);
  }).catch((error: BusinessError) => {
    console.error("[Promise]: error: " + error.message);
  });
}

// Generate a digest in callback mode.
function doMdByCallback() {
  let mdAlgName = "SHA256"; // Digest algorithm name.
  let message = "mdTestMessgae"; // Data to be digested.
  let md = cryptoFramework.createMd(mdAlgName);
  console.info("[Callback]: Md algName is: " + md.algName);
  // If the data volume is small, you can use update() once to pass in all data. There is no limit on the length of the input parameter.
  md.update({ data: stringToUint8Array(message) }, (err,) => {
    if (err) {
      console.error("[Callback]: err: " + err.code);
    }
    md.digest((err1, digestOutput) => {
      if (err1) {
        console.error("[Callback]: err: " + err1.code);
      } else {
        let mdOutput = digestOutput;
        console.info("[Callback]: MD result: " + mdOutput.data);
        let mdLen = md.getMdLength();
        console.info("[Callback]: MD len: " + mdLen);
      }
    });
  });
}

Generating a Digest by Segment

1. Use createMd() to create an Md instance.
2. Use update() multiple times to pass in by segment.
3. Use digest() to compute a digest.
4. Obtain the digest algorithm and length of the digest generated.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Generate a digest by segment in promise mode.
async function doLoopMdPromise() {
  let mdAlgName = "SHA256"; // Digest algorithm name.
  let md = cryptoFramework.createMd(mdAlgName);
  ;
  console.info("[Promise]: Md algName is: " + md.algName);
  let messageText = "aaaaa.....bbbbb.....ccccc.....ddddd.....eee"; // Assume that the message is of 43 bytes.
  let messageArr: number[] = [];
  let updateLength = 20; // For example, pass in 20 bytes in each update().

  for (let i = 0; i <= messageText.length; i++) {
    if ((i % updateLength == 0||i == messageText.length) && messageArr.length != 0) {
      let message = new Uint8Array(messageArr);
      let messageBlob: cryptoFramework.DataBlob = { data: message };
      // Use await to process the update() in the for() loop.
      try {
        await md.update(messageBlob); // Use update() to process data by segment.
      } catch (error) {
        let e: BusinessError = error as BusinessError;
        console.error(`await update error, ${e.code}, ${e.message}`);
        return;
      }
      messageArr = [];
    }
    // Pad messageArr based on the segment length.
    if (i < messageText.length) {
      messageArr.push(messageText.charCodeAt(i));
    }
  }
  let PromiseMdDigest = md.digest();
  PromiseMdDigest.then(digestOutput => {
    let mdOutput = digestOutput;
    console.info("[Promise]: MD result: " + mdOutput.data);
    let mdLen = md.getMdLength();
    console.info("[Promise]: MD len: " + mdLen);
  }).catch((error: BusinessError) => {
    console.error("[Promise]: error: " + error.message);
  });
}

HMAC

When to Use

A hash-based message authentication code (HMAC) can be used to verify both the integrity and authenticity of a message using a shared secret.

Typical MAC operations involve the following:

1. Create a Mac instance.
2. Initialize the Mac instance, add one or more segments of data for generating a MAC, and generate a MAC.
3. Obtain the algorithm and length of a MAC.

Available APIs

For details about the APIs, see Crypto Framework.

Generating an HMAC

1. Use createMac() to create a Mac instance.
2. Use init() to initialize the Mac instance with the symmetric key passed in.
3. Use update() to pass in the data for computing an HMAC.
4. Use doFinal() to generate an HMAC.
5. Obtain the algorithm and length of the HMAC.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Convert strings in plaintext into byte streams.
function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

// Generate an HMAC in promise mode.
function doHmacByPromise() {
  let macAlgName = "SHA256"; // Digest algorithm name.
  let message = "hmacTestMessgae"; // Data used to generate an HMAC.
  let mac = cryptoFramework.createMac(macAlgName);
  console.info("[Promise]: Mac algName is: " + mac.algName);
  let KeyBlob: cryptoFramework.DataBlob = {
    // 128-bit key
    data: stringToUint8Array("12345678abcdefgh")
  }
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("AES128");
  // Convert the binary data into a key.
  let promiseConvertKey = symKeyGenerator.convertKey(KeyBlob);
  promiseConvertKey.then(symKey => {
    let promiseMacInit = mac.init(symKey);
    return promiseMacInit;
  })
    .then(() => {
      // If the data volume is small, you can use update() once to pass in all data. There is no limit on the length of the input parameter.
      let promiseMacUpdate = mac.update({ data: stringToUint8Array(message) });
      return promiseMacUpdate;
    })
    .then(() => {
      let PromiseMacDoFinal = mac.doFinal();
      return PromiseMacDoFinal;
    })
    .then(output => {
      let macOutput = output;
      console.info("[Promise]: HMAC result: " + macOutput.data);
      let macLen = mac.getMacLength();
      console.info("[Promise]: MAC len: " + macLen);
    })
    .catch((error: BusinessError) => {
      console.error("[Promise]: error: " + error.message);
    });
}

// Generate an HMAC in callback mode.
function doHmacByCallback() {
  let macAlgName = "SHA256"; // Digest algorithm name.
  let message = "hmacTestMessgae"; // Data used to generate an HMAC.
  let mac = cryptoFramework.createMac(macAlgName);
  console.info("[Promise]: Mac algName is: " + mac.algName);
  let KeyBlob: cryptoFramework.DataBlob = {
    // 128-bit key
    data: stringToUint8Array("12345678abcdefgh")
  }
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("AES128");
  // Convert the binary data into a key.
  symKeyGenerator.convertKey(KeyBlob, (err, symKey) => {
    if (err) {
      console.error("[Callback]: err: " + err.code);
    }
    mac.init(symKey, (err1,) => {
      if (err1) {
        console.error("[Callback]: err: " + err1.code);
      }
      // If the data volume is small, you can use update() once to pass in all data. There is no limit on the length of the input parameter.
      mac.update({ data: stringToUint8Array(message) }, (err2,) => {
        if (err2) {
          console.error("[Callback]: err: " + err2.code);
        }
        mac.doFinal((err3, output) => {
          if (err3) {
            console.error("[Callback]: err: " + err3.code);
          } else {
            let macOutput = output;
            console.error("[Callback]: HMAC result: " + macOutput.data);
            let macLen = mac.getMacLength();
            console.error("[Callback]: MAC len: " + macLen);
          }
        });
      });
    });
  });
}

Generating an HMAC by Segment

Generate an HMAC by segment.

1. Use createMac() to create a Mac instance.
2. Use init() to initialize the Mac instance with the symmetric key passed in.
3. Call update() multiple times to pass in data by segment.
4. Use doFinal() to generate an HMAC.
5. Obtain the algorithm and length of the HMAC.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

function stringToUint8Array(str: string) {
  let arr = new Uint8Array(str.length);
  for (let i = 0, j = str.length; i < j; ++i) {
    arr[i] = str.charCodeAt(i);
  }
  return arr;
}

function doLoopHmacPromise() {
  let macAlgName = "SHA256"; // Digest algorithm name.
  let mac = cryptoFramework.createMac(macAlgName);
  console.info("[Promise]: Mac algName is: " + mac.algName);
  let KeyBlob: cryptoFramework.DataBlob = {
    // 128-bit key
    data: stringToUint8Array("12345678abcdefgh")
  }
  let messageText = "aaaaa.....bbbbb.....ccccc.....ddddd.....eee"; // Assume that the message is of 43 bytes.
  let updateLength = 20; // For example, pass in 20 bytes in each update().
  let symKeyGenerator = cryptoFramework.createSymKeyGenerator("AES128");
  // Convert the binary data into a key.
  let promiseConvertKey = symKeyGenerator.convertKey(KeyBlob);
  promiseConvertKey.then((symKey: cryptoFramework.SymKey): Promise<void> => {
    let promiseMacInit = mac.init(symKey);
    return promiseMacInit;
  })
    .then(async () => {
      let messageArr: number[] = [];
      for (let i = 0; i <= messageText.length; i++) {
        if ((i % updateLength == 0||i == messageText.length) && messageArr.length != 0) {
          let message = new Uint8Array(messageArr);
          let messageBlob: cryptoFramework.DataBlob = { data: message };
          // Use await to process the update() in the for() loop.
          try {
            await mac.update(messageBlob); // Invoke update() multiple times.
          } catch (error) {
            let e: BusinessError = error as BusinessError;
            console.error(`await update error, ${e.code}, ${e.message}`);
            return;
          }
          messageArr = [];
        }
        // Pad messageArr based on the segment length.
        if (i < messageText.length) {
          messageArr.push(messageText.charCodeAt(i));
        }
      }
      return;
    })
    .then(() => {
      let PromiseMacDoFinal = mac.doFinal();
      return PromiseMacDoFinal;
    })
    .then(output => {
      let macOutput = output;
      console.log("[Promise]: HMAC result: " + macOutput.data);
      let macLen = mac.getMacLength();
      console.log("[Promise]: MAC len: " + macLen);
    })
    .catch((error: BusinessError) => {
      console.error("[Promise]: error: " + error.message);
    });
}

Random Number

When to Use

Typical random number operations involve the following:

1. Create a Random instance and specify the length (in bytes) of the random number to generate a secure random number of the specified length (ranging from 1 to INT_MAX).
2. Set a seed based on the random number generated.

Available APIs

For more information about the APIs, see Crypto Framework.

How to Develop

1. Use createRandom() to create a Random instance.
2. Use generateRandom() to generate a random number of the given length.
3. Use setSeed() to set a seed.

import cryptoFramework from '@ohos.security.cryptoFramework';
import { BusinessError } from '@ohos.base';

// Generate a random number in promise mode.
function doRandByPromise() {
  let rand = cryptoFramework.createRandom();
  let len = 4; // Generate a 4-byte random number.
  let promiseGenerateRand = rand.generateRandom(len);
  promiseGenerateRand.then(randData => {
    console.info("[Promise]: rand result: " + randData.data);
    try {
      rand.setSeed(randData);
    } catch (error) {
      let e: BusinessError = error as BusinessError;
      console.error(`setSeed failed, ${e.code}, ${e.message}`);
    }
  }).catch((error: BusinessError) => {
    console.error("[Promise]: error: " + error.message);
  });
}

// Generate a random number in callback mode.
function doRandByCallback() {
  let rand = cryptoFramework.createRandom();
  let len = 4; // Generate a 4-byte random number.
  rand.generateRandom(len, (err, randData) => {
    if (err) {
      console.error("[Callback]: err: " + err.code);
    } else {
      console.info("[Callback]: generate random result: " + randData.data);
      try {
        rand.setSeed(randData);
      } catch (error) {
        let e: BusinessError = error as BusinessError;
        console.error(`setSeed failed, ${e.code}, ${e.message}`);
      }
    }
  });
}

// Generate a random number synchronously.
function doRandBySync() {
  let rand = cryptoFramework.createRandom();
  let len = 24; // Generate a 24-byte random number.
  try {
    let randData = rand.generateRandomSync(len);
    if (randData != null) {
      console.info("[Sync]: rand result: " + randData.data);
    } else {
      console.error("[Sync]: get rand result fail!");
    }
  } catch (error) {
    let e: BusinessError = error as BusinessError;
    console.error(`do rand failed, ${e.code}, ${e.message}`);
  }
}

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