# 使用AES对称密钥（CCM模式）参数为AeadParamsSpec加解密(ArkTS)

从API版本26.0.0开始，AES对称密钥（CCM模式）的加解密支持使用AeadParamsSpec参数。

当用户不希望显式保存authTag或用户需要指定authTag的长度时，使用AeadParamsSpec参数。

**密钥生成**

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进行理解，参考文档与当前示例可能存在入参差异，请注意区分。

**加密**

1.  调用cryptoFramework.createCipher，指定字符串参数'AES128|CCM'，创建对称密钥为AES128、分组模式为CCM的Cipher实例，用于执行加密操作。
    
2.  调用Cipher.init，设置模式为加密（cryptoFramework.CryptoMode.ENCRYPT\_MODE），指定密钥（SymKey）和CCM模式对应的加密参数（AeadParamsSpec），初始化加密Cipher实例。
    
3.  调用Cipher.doFinal获取加密后的数据。
    
    当前使用AeadParamsSpec参数，CCM模式下update与doFinal只能调用其中一个进行加密。且每个方法只能调用一次。
    
    使用AeadParamsSpec初始化Cipher实例，身份认证标签（authTag）自动拼接在密文后，不需要单独保存。
    
    在使用AeadParamsSpec结构的CCM模式下，tagLen支持4、6、8、10、12、14和16，如果不传默认为12，单位均为字节。
    

**解密**

1.  调用cryptoFramework.createCipher，指定字符串参数'AES128|CCM'，创建对称密钥为AES128、分组模式为CCM的Cipher实例，用于完成解密操作。
    
2.  调用Cipher.init，设置模式为解密（cryptoFramework.CryptoMode.DECRYPT\_MODE），指定密钥（SymKey）和CCM模式对应的解密参数（AeadParamsSpec），初始化解密Cipher实例。
    
3.  调用Cipher.doFinal，获取解密后的数据。
    

#### 示例

*   异步方法示例：
    
    ```
    import { cryptoFramework } from '@kit.CryptoArchitectureKit';
    import { buffer } from '@kit.ArkTS';
    
    function genCcmAeadParamsSpec() {
      let nonce = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; // 12 bytes
      let nonceValue = new Uint8Array(nonce);
      let aad = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; // 12 bytes
      let aadValue = new Uint8Array(aad);
      let aeadParamsSpec: cryptoFramework.AeadParamsSpec = {
          nonce: nonceValue,
          authenticatedData: aadValue,
          algName: 'AeadParamsSpec'
      };
      return aeadParamsSpec;
    }
    
      let aeadParams = genCcmAeadParamsSpec();
    
    // 加密消息
    async function encryptMessagePromise(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
      let cipher = cryptoFramework.createCipher('AES128|CCM');
      await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, aeadParams);
      let encryptUpdate = await cipher.doFinal(plainText);
      return encryptUpdate;
    }
    
    // 解密消息
    async function decryptMessagePromise(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
      let decoder = cryptoFramework.createCipher('AES128|CCM');
      await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, aeadParams);
      let decryptUpdate = await decoder.doFinal(cipherText);
      return decryptUpdate;
    }
    
    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 result: success.');
      return symKey;
    }
    
    export async function main() : Promise<string> {
      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.');
        }
        return 'success';
      } catch (error) {
        console.error('decrypt failed. error: ' + error);
        return 'fail';
      }
    }
    ```
    
*   同步方法示例：
    
    ```
    import { cryptoFramework } from '@kit.CryptoArchitectureKit';
    import { buffer } from '@kit.ArkTS';
    
    function genCcmAeadParamsSpec() {
      let nonce = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; // 12 bytes
      let nonceValue = new Uint8Array(nonce);
      let aad = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; // 12 bytes
      let aadValue = new Uint8Array(aad);
      let aeadParamsSpec: cryptoFramework.AeadParamsSpec = {
          nonce: nonceValue,
          authenticatedData: aadValue,
          algName: 'AeadParamsSpec'
      };
      return aeadParamsSpec;
    }
    
      let aeadParams = genCcmAeadParamsSpec();
    
    // 加密消息
    function encryptMessage(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
      let cipher = cryptoFramework.createCipher('AES128|CCM');
      cipher.initSync(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, aeadParams);
      let encryptUpdate = cipher.doFinalSync(plainText);
      return encryptUpdate;
    }
    
    // 解密消息
    function decryptMessage(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
      let decoder = cryptoFramework.createCipher('AES128|CCM');
      decoder.initSync(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, aeadParams);
      let decryptUpdate = decoder.doFinalSync(cipherText);
      return decryptUpdate;
    }
    
    function genSymKeyByData(symKeyData: Uint8Array) {
      let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
      let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
      let symKey = aesGenerator.convertKeySync(symKeyBlob);
      console.info('convertKeySync result: success.');
      return symKey;
    }
    
    export function main() : string {
      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.');
        }
        return 'success';
      } catch (error) {
        console.error('decrypt failed. error: ' + error);
        return 'fail';
      }
    }
    ```