使用AES对称密钥（CBC模式）加解密(ArkTS)

对应的算法规格请参见对称密钥加解密算法规格：AES。

加密

1. 调用cryptoFramework.createSymKeyGenerator、SymKeyGenerator.generateSymKey，生成密钥算法为AES、密钥长度为128位的对称密钥（SymKey）。

   如何生成AES对称密钥，开发者可参考下文示例，并结合对称密钥生成和转换规格：AES和随机生成对称密钥理解，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'AES128|CBC|PKCS7'，创建对称密钥类型为AES128、分组模式为CBC、填充模式为PKCS7的Cipher实例，用于完成加密操作。

3. 调用Cipher.init，设置模式为加密（CryptoMode.ENCRYPT_MODE），指定加密密钥（SymKey）和CBC模式对应的加密参数（IvParamsSpec），初始化加密Cipher实例。

4. 当加密内容长度较短时，可以直接调用 Cipher.doFinal 而无需调用update，以获取加密后的数据。

解密

1. 调用cryptoFramework.createCipher，指定字符串参数'AES128|CBC|PKCS7'，创建对称密钥类型为AES128、分组模式为CBC、填充模式为PKCS7的Cipher实例，用于完成解密操作。

2. 调用Cipher.init，设置模式为解密（CryptoMode.DECRYPT_MODE），指定解密密钥（SymKey）和CBC模式对应的解密参数（IvParamsSpec），初始化解密Cipher实例。

3. 当解密内容长度较短时，可以省略调用update，直接调用Cipher.doFinal，获取解密后的数据。

• 异步方法示例：

  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
  import { buffer } from '@kit.ArkTS';
  
  function generateRandom(len: number) {
    let rand = cryptoFramework.createRandom();
    let generateRandSync = rand.generateRandomSync(len);
    return generateRandSync;
  }
  
  function genIvParamsSpec() {
    let ivBlob = generateRandom(16);
    let ivParamsSpec: cryptoFramework.IvParamsSpec = {
      algName: "IvParamsSpec",
      iv: ivBlob
    };
    return ivParamsSpec;
  }
  let iv = genIvParamsSpec();
  // 加密消息。
  async function encryptMessagePromise(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
    let cipher = cryptoFramework.createCipher('AES128|CBC|PKCS7');
    await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, iv);
    let cipherData = await cipher.doFinal(plainText);
    return cipherData;
  }
  // 解密消息。
  async function decryptMessagePromise(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
    let decoder = cryptoFramework.createCipher('AES128|CBC|PKCS7');
    await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, iv);
    let decryptData = await decoder.doFinal(cipherText);
    return decryptData;
  }
  
  async function genSymKeyByData(symKeyData: Uint8Array) {
    let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
    let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
    let symKey = await aesGenerator.convertKey(symKeyBlob);
    console.info('convertKey success');
    return symKey;
  }
  
  async function aesCBC() {
    try {
      let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);
      let symKey = await genSymKeyByData(keyData);
      let message = "This is a test";
      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
      let encryptText = await encryptMessagePromise(symKey, plainText);
      let decryptText = await decryptMessagePromise(symKey, encryptText);
      if (plainText.data.toString() === decryptText.data.toString()) {
        console.info('decrypt ok');
        console.info('decrypt plainText: ' + buffer.from(decryptText.data).toString('utf-8'));
      } else {
        console.error('decrypt failed');
      }
    } catch (error) {
      console.error(`AES CBC "${error}" error code: ${error.code}`);
    }
  }
  

• 同步方法示例：

  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
  import { buffer } from '@kit.ArkTS';
  
  function generateRandom(len: number) {
    let rand = cryptoFramework.createRandom();
    let generateRandSync = rand.generateRandomSync(len);
    return generateRandSync;
  }
  
  function genIvParamsSpec() {
    let ivBlob = generateRandom(16);
    let ivParamsSpec: cryptoFramework.IvParamsSpec = {
      algName: "IvParamsSpec",
      iv: ivBlob
    };
    return ivParamsSpec;
  }
  let iv = genIvParamsSpec();
  // 加密消息。
  function encryptMessage(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
    let cipher = cryptoFramework.createCipher('AES128|CBC|PKCS7');
    cipher.initSync(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, iv);
    let cipherData = cipher.doFinalSync(plainText);
    return cipherData;
  }
  // 解密消息。
  function decryptMessage(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
    let decoder = cryptoFramework.createCipher('AES128|CBC|PKCS7');
    decoder.initSync(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, iv);
    let decryptData = decoder.doFinalSync(cipherText);
    return decryptData;
  }
  
  function genSymKeyByData(symKeyData: Uint8Array) {
    let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
    let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
    let symKey = aesGenerator.convertKeySync(symKeyBlob);
    console.info('convertKeySync success');
    return symKey;
  }
  
  function main() {
    try {
      let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);
      let symKey = genSymKeyByData(keyData);
      let message = "This is a test";
      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
      let encryptText = encryptMessage(symKey, plainText);
      let decryptText = decryptMessage(symKey, encryptText);
      if (plainText.data.toString() === decryptText.data.toString()) {
        console.info('decrypt ok');
        console.info('decrypt plainText: ' + buffer.from(decryptText.data).toString('utf-8'));
      } else {
        console.error('decrypt failed');
      }
    } catch (error) {
      console.error(`AES CBC "${error}" error code: ${error.code}`);
    }
  }