Converting SM2 Signature Formats (ArkTS)

HarmonyOS supports the conversion between the DER and R|S formats.

You can specify SM2 signature parameters and convert them to DER ciphertext. You can also extract SM2 signature data from DER ciphertext.

Converting Ciphertext Parameters to DER Ciphertext

Create an EccSignatureSpec instance to specify SM2 ciphertext parameters.
Call genEccSignature to pass the EccSignatureSpec object to convert it to SM2 ciphertext in DER format.

import { cryptoFramework } from '@kit.CryptoArchitectureKit';
import { BusinessError } from '@kit.BasicServicesKit';

function testSm2SignDataRsToDer() {
  try {
    let spec: cryptoFramework.EccSignatureSpec = {
      r: BigInt('97726608965854271693043443511967021777934035174185659091642456228829830775155'),
      s: BigInt('23084224202834231287427338597254751764391338275617140205467537273296855150376'),
    };

    let data = cryptoFramework.SignatureUtils.genEccSignature(spec);
    console.info('genEccSignature result: success.');
    console.info('data = ' + data);
  } catch (err) {
    let e: BusinessError = err as BusinessError;
    console.error(`ecc failed: errCode: ${e.code}, message: ${e.message}`);
  }
}

Converting DER Ciphertext to the R and S Parameters

Specifies the SM2 ciphertext parameters in DER format.
Call genEccSignatureSpec to pass data in DER format and convert the data into SM2 ciphertext in R|S format.

import { cryptoFramework } from '@kit.CryptoArchitectureKit';
import { BusinessError } from '@kit.BasicServicesKit';

function testSm2SignDataDerToRs() {
  try {
    let data =
      new Uint8Array([48, 69, 2, 33, 0, 216, 15, 76, 238, 158, 165, 108, 76, 72, 63, 115, 52, 255, 51, 149, 54, 224,
        179, 49, 225, 70, 36, 117, 88, 154, 154, 27, 194, 161, 3, 1, 115, 2, 32, 51, 9, 53, 55, 248, 82, 7, 159, 179,
        144, 57, 151, 195, 17, 31, 106, 123, 32, 139, 219, 6, 253, 62, 240, 181, 134, 214, 107, 27, 230, 175, 40]);
    let spec: cryptoFramework.EccSignatureSpec = cryptoFramework.SignatureUtils.genEccSignatureSpec(data);
    console.info('genEccSignatureSpec result: success.');
  } catch (err) {
    let e: BusinessError = err as BusinessError;
    console.error(`ecc failed: errCode: ${e.code}, message: ${e.message}`);
  }
}