# 使用SM2非对称密钥加解密(ArkTS)

对应的算法规格请查看非对称密钥加解密算法规格：SM2。

**加密**

1.  调用cryptoFramework.createAsyKeyGenerator、AsyKeyGenerator.generateKeyPair，生成SM2密钥类型为SM2\_256的非对称密钥对（KeyPair）。KeyPair对象中包括公钥PubKey、私钥PriKey。
    
    如何生成SM2非对称密钥对，开发者可参考下文示例，并结合非对称密钥生成和转换规格：SM2和随机生成非对称密钥对理解，参考文档与当前示例可能存在入参差异，请在阅读时注意区分。
    
2.  调用cryptoFramework.createCipher，指定字符串参数'SM2\_256|SM3'，创建非对称密钥类型为SM2\_256、摘要算法为SM3的Cipher实例，用于完成加解密操作。
    
3.  调用Cipher.init，设置模式为加密（cryptoFramework.CryptoMode.ENCRYPT\_MODE），指定加密密钥（KeyPair.PubKey），初始化加密Cipher实例。
    
    非对称密钥无加密参数，直接传入null。
    
4.  调用Cipher.doFinal，传入明文，获取加密后的数据。
    
    doFinal输出结果可能为null，在访问具体数据前，需要先判断结果是否为null，避免产生异常。
    

**解密**

1.  由于SM2算法的Cipher实例不支持重复init操作，需要调用cryptoFramework.createCipher，重新生成Cipher实例。
    
2.  调用Cipher.init，设置模式为解密（cryptoFramework.CryptoMode.DECRYPT\_MODE），指定解密密钥（KeyPair.PriKey）初始化解密Cipher实例。SM2无加密参数，直接传入null。
    
3.  调用Cipher.doFinal，传入密文，获取解密后的数据。
    

*   异步方法示例：
    
    ```
    import { cryptoFramework } from '@kit.CryptoArchitectureKit';
    import { buffer } from '@kit.ArkTS';
    
    // 加密消息
    async function encryptMessagePromise(publicKey: cryptoFramework.PubKey, plainText: cryptoFramework.DataBlob) {
      let cipher = cryptoFramework.createCipher('SM2_256|SM3');
      await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, publicKey, null);
      let encryptData = await cipher.doFinal(plainText);
      return encryptData;
    }
    
    // 解密消息
    async function decryptMessagePromise(privateKey: cryptoFramework.PriKey, cipherText: cryptoFramework.DataBlob) {
      let decoder = cryptoFramework.createCipher('SM2_256|SM3');
      await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, privateKey, null);
      let decryptData = await decoder.doFinal(cipherText);
      return decryptData;
    }
    
    // 生成SM2密钥对
    async function genKeyPairByData(pubKeyData: Uint8Array, priKeyData: Uint8Array) {
      let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyData };
      let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyData };
      let sm2Generator = cryptoFramework.createAsyKeyGenerator('SM2_256');
      let keyPair = await sm2Generator.convertKey(pubKeyBlob, priKeyBlob);
      console.info('convertKey result: success.');
      return keyPair;
    }
    
    async function main() {
      let pkData =
        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 skData =
        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 keyPair = await genKeyPairByData(pkData, skData);
      let pubKey = keyPair.pubKey;
      let priKey = keyPair.priKey;
      let message = 'This is a test';
      // 把字符串按utf-8解码为Uint8Array
      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
      let encryptText = await encryptMessagePromise(pubKey, plainText);
      let decryptText = await decryptMessagePromise(priKey, encryptText);
      if (plainText.data.toString() === decryptText.data.toString()) {
        console.info('decrypt ok.');
        // 把Uint8Array按utf-8编码为字符串
        let messageDecrypted = buffer.from(decryptText.data).toString('utf-8');
        console.info('decrypted result string:' + messageDecrypted);
      } else {
        console.error('decrypt failed.');
      }
    }
    ```
    
*   同步方法示例：
    
    ```
    import { cryptoFramework } from '@kit.CryptoArchitectureKit';
    import { buffer } from '@kit.ArkTS';
    
    // 加密消息
    function encryptMessage(publicKey: cryptoFramework.PubKey, plainText: cryptoFramework.DataBlob) {
      let cipher = cryptoFramework.createCipher('SM2_256|SM3');
      cipher.initSync(cryptoFramework.CryptoMode.ENCRYPT_MODE, publicKey, null);
      let encryptData = cipher.doFinalSync(plainText);
      return encryptData;
    }
    
    // 解密消息
    function decryptMessage(privateKey: cryptoFramework.PriKey, cipherText: cryptoFramework.DataBlob) {
      let decoder = cryptoFramework.createCipher('SM2_256|SM3');
      decoder.initSync(cryptoFramework.CryptoMode.DECRYPT_MODE, privateKey, null);
      let decryptData = decoder.doFinalSync(cipherText);
      return decryptData;
    }
    
    // 生成SM2密钥对
    function genKeyPairByData(pubKeyData: Uint8Array, priKeyData: Uint8Array) {
      let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyData };
      let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyData };
      let sm2Generator = cryptoFramework.createAsyKeyGenerator('SM2_256');
      let keyPair = sm2Generator.convertKeySync(pubKeyBlob, priKeyBlob);
      console.info('convertKeySync result: success.');
      return keyPair;
    }
    
    function main() {
      let pkData =
        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 skData =
        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 keyPair = genKeyPairByData(pkData, skData);
      let pubKey = keyPair.pubKey;
      let priKey = keyPair.priKey;
      let message = 'This is a test';
      // 把字符串按utf-8解码为Uint8Array
      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
      let encryptText = encryptMessage(pubKey, plainText);
      let decryptText = decryptMessage(priKey, encryptText);
      if (plainText.data.toString() === decryptText.data.toString()) {
        console.info('decrypt ok.');
        // 把Uint8Array按utf-8编码为字符串
        let messageDecrypted = buffer.from(decryptText.data).toString('utf-8');
        console.info('decrypted result string:' + messageDecrypted);
      } else {
        console.error('decrypt failed.');
      }
    }
    ```