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1# 使用AES对称密钥（CBC模式）加解密(ArkTS)
2
3<!--Kit: Crypto Architecture Kit-->
4<!--Subsystem: Security-->
5<!--Owner: @zxz--3-->
6<!--Designer: @lanming-->
7<!--Tester: @PAFT-->
8<!--Adviser: @zengyawen-->
9
10对应的算法规格请参见[对称密钥加解密算法规格：AES](crypto-sym-encrypt-decrypt-spec.md#aes)。
11
12**加密**
13
141. 调用[cryptoFramework.createSymKeyGenerator](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreatesymkeygenerator)、[SymKeyGenerator.generateSymKey](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#generatesymkey-1)，生成密钥算法为AES、密钥长度为128位的对称密钥（SymKey）。
15
16   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](crypto-sym-key-generation-conversion-spec.md#aes)和[随机生成对称密钥](crypto-generate-sym-key-randomly.md)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。
17
182. 调用[cryptoFramework.createCipher](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreatecipher)，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。
19
203. 调用[Cipher.init](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#init-1)，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。
21
224. 当加密内容长度较短时，可以直接调用 [Cipher.doFinal](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#dofinal-1) 而无需调用update，以获取加密后的数据。
23
24**解密**
25
261. 调用[cryptoFramework.createCipher](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreatecipher)，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。
27
282. 调用[Cipher.init](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#init-1)，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。
29
303. 当解密内容长度较短时，可以省略调用update，直接调用[Cipher.doFinal](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#dofinal-1)，获取解密后的数据。
31
32- 异步方法示例：
33
34  ```ts
35  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
36  import { buffer } from '@kit.ArkTS';
37
38  function generateRandom(len: number) {
39    let rand = cryptoFramework.createRandom();
40    let generateRandSync = rand.generateRandomSync(len);
41    return generateRandSync;
42  }
43
44  function genIvParamsSpec() {
45    let ivBlob = generateRandom(16);
46    let ivParamsSpec: cryptoFramework.IvParamsSpec = {
47      algName: "IvParamsSpec",
48      iv: ivBlob
49    };
50    return ivParamsSpec;
51  }
52  let iv = genIvParamsSpec();
53  // 加密消息。
54  async function encryptMessagePromise(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
55    let cipher = cryptoFramework.createCipher('AES128|CBC|PKCS7');
56    await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, iv);
57    let cipherData = await cipher.doFinal(plainText);
58    return cipherData;
59  }
60  // 解密消息。
61  async function decryptMessagePromise(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
62    let decoder = cryptoFramework.createCipher('AES128|CBC|PKCS7');
63    await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, iv);
64    let decryptData = await decoder.doFinal(cipherText);
65    return decryptData;
66  }
67
68  async function genSymKeyByData(symKeyData: Uint8Array) {
69    let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
70    let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
71    let symKey = await aesGenerator.convertKey(symKeyBlob);
72    console.info('convertKey success');
73    return symKey;
74  }
75
76  async function aesCBC() {
77    try {
78      let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);
79      let symKey = await genSymKeyByData(keyData);
80      let message = "This is a test";
81      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
82      let encryptText = await encryptMessagePromise(symKey, plainText);
83      let decryptText = await decryptMessagePromise(symKey, encryptText);
84      if (plainText.data.toString() === decryptText.data.toString()) {
85        console.info('decrypt ok');
86        console.info('decrypt plainText: ' + buffer.from(decryptText.data).toString('utf-8'));
87      } else {
88        console.error('decrypt failed');
89      }
90    } catch (error) {
91      console.error(`AES CBC "${error}", error code: ${error.code}`);
92    }
93  }
94  ```
95
96- 同步方法示例：
97
98  ```ts
99  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
100  import { buffer } from '@kit.ArkTS';
101
102  function generateRandom(len: number) {
103    let rand = cryptoFramework.createRandom();
104    let generateRandSync = rand.generateRandomSync(len);
105    return generateRandSync;
106  }
107
108  function genIvParamsSpec() {
109    let ivBlob = generateRandom(16);
110    let ivParamsSpec: cryptoFramework.IvParamsSpec = {
111      algName: "IvParamsSpec",
112      iv: ivBlob
113    };
114    return ivParamsSpec;
115  }
116  let iv = genIvParamsSpec();
117  // 加密消息。
118  function encryptMessage(symKey: cryptoFramework.SymKey, plainText: cryptoFramework.DataBlob) {
119    let cipher = cryptoFramework.createCipher('AES128|CBC|PKCS7');
120    cipher.initSync(cryptoFramework.CryptoMode.ENCRYPT_MODE, symKey, iv);
121    let cipherData = cipher.doFinalSync(plainText);
122    return cipherData;
123  }
124  // 解密消息。
125  function decryptMessage(symKey: cryptoFramework.SymKey, cipherText: cryptoFramework.DataBlob) {
126    let decoder = cryptoFramework.createCipher('AES128|CBC|PKCS7');
127    decoder.initSync(cryptoFramework.CryptoMode.DECRYPT_MODE, symKey, iv);
128    let decryptData = decoder.doFinalSync(cipherText);
129    return decryptData;
130  }
131
132  function genSymKeyByData(symKeyData: Uint8Array) {
133    let symKeyBlob: cryptoFramework.DataBlob = { data: symKeyData };
134    let aesGenerator = cryptoFramework.createSymKeyGenerator('AES128');
135    let symKey = aesGenerator.convertKeySync(symKeyBlob);
136    console.info('convertKeySync success');
137    return symKey;
138  }
139
140  function main() {
141    try {
142      let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);
143      let symKey = genSymKeyByData(keyData);
144      let message = "This is a test";
145      let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
146      let encryptText = encryptMessage(symKey, plainText);
147      let decryptText = decryptMessage(symKey, encryptText);
148      if (plainText.data.toString() === decryptText.data.toString()) {
149        console.info('decrypt ok');
150        console.info('decrypt plainText: ' + buffer.from(decryptText.data).toString('utf-8'));
151      } else {
152        console.error('decrypt failed');
153      }
154    } catch (error) {
155      console.error(`AES CBC "${error}", error code: ${error.code}`);
156    }
157  }
158  ```