1# 使用SM2非对称密钥加解密
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3
4对应的算法规格请查看[非对称密钥加解密算法规格：SM2](crypto-asym-encrypt-decrypt-spec.md#sm2)。
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6
7**加密**
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9
101. 调用[cryptoFramework.createAsyKeyGenerator](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreateasykeygenerator)、[AsyKeyGenerator.generateKeyPair](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#generatekeypair-1)，生成RSA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。
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12   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](crypto-asym-key-generation-conversion-spec.md#sm2)和[随机生成非对称密钥对](crypto-generate-asym-key-pair-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。
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142. 调用[cryptoFramework.createCipher](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreatecipher)，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。
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163. 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（KeyPair.PubKey），初始化加密Cipher实例。
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18   非对称密钥无加密参数，直接传入null。
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204. 调用[Cipher.doFinal](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#dofinal-1)，传入明文，获取加密后的数据。
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22   - 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。
23   - 当数据量较大时，可以多次调用doFinal，即分段加解密。
24
25
26**解密**
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291. 由于SM2算法的Cipher实例不支持重复init操作，需要调用[cryptoFramework.createCipher](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreatecipher)，重新生成Cipher实例。
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312. 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（KeyPair.PriKey）初始化解密Cipher实例。SM2无加密参数，直接传入null。
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333. 调用[Cipher.doFinal](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#dofinal-1)，传入密文，获取解密后的数据。
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35
36- 异步方法示例：
37
38  ```ts
39  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
40  import { buffer } from '@kit.ArkTS';
41
42  // 加密消息
43  async function encryptMessagePromise(publicKey: cryptoFramework.PubKey, plainText: cryptoFramework.DataBlob) {
44    let cipher = cryptoFramework.createCipher('SM2_256|SM3');
45    await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, publicKey, null);
46    let encryptData = await cipher.doFinal(plainText);
47    return encryptData;
48  }
49  // 解密消息
50  async function decryptMessagePromise(privateKey: cryptoFramework.PriKey, cipherText: cryptoFramework.DataBlob) {
51    let decoder = cryptoFramework.createCipher('SM2_256|SM3');
52    await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, privateKey, null);
53    let decryptData = await decoder.doFinal(cipherText);
54    return decryptData;
55  }
56  // 生成SM2密钥对
57  async function genKeyPairByData(pubKeyData: Uint8Array, priKeyData: Uint8Array) {
58    let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyData };
59    let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyData };
60    let sm2Generator = cryptoFramework.createAsyKeyGenerator('SM2_256');
61    let keyPair = await sm2Generator.convertKey(pubKeyBlob, priKeyBlob);
62    console.info('convertKey success');
63    return keyPair;
64  }
65  async function main() {
66    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]);
67    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]);
68    let keyPair = await genKeyPairByData(pkData, skData);
69    let pubKey = keyPair.pubKey;
70    let priKey = keyPair.priKey;
71    let message = 'This is a test';
72    // 把字符串按utf-8解码为Uint8Array
73    let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
74    let encryptText = await encryptMessagePromise(pubKey, plainText);
75    let decryptText = await decryptMessagePromise(priKey, encryptText);
76    if (plainText.data.toString() === decryptText.data.toString()) {
77      console.info('decrypt ok');
78      // 把Uint8Array按utf-8编码为字符串
79      let messageDecrypted = buffer.from(decryptText.data).toString('utf-8');
80      console.info('decrypted result string:' + messageDecrypted);
81    } else {
82      console.error('decrypt failed');
83    }
84  }
85  ```
86
87- 同步方法示例：
88
89  ```ts
90  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
91  import { buffer } from '@kit.ArkTS';
92
93  // 加密消息
94  function encryptMessage(publicKey: cryptoFramework.PubKey, plainText: cryptoFramework.DataBlob) {
95    let cipher = cryptoFramework.createCipher('SM2_256|SM3');
96    cipher.initSync(cryptoFramework.CryptoMode.ENCRYPT_MODE, publicKey, null);
97    let encryptData = cipher.doFinalSync(plainText);
98    return encryptData;
99  }
100  // 解密消息
101  function decryptMessage(privateKey: cryptoFramework.PriKey, cipherText: cryptoFramework.DataBlob) {
102    let decoder = cryptoFramework.createCipher('SM2_256|SM3');
103    decoder.initSync(cryptoFramework.CryptoMode.DECRYPT_MODE, privateKey, null);
104    let decryptData = decoder.doFinalSync(cipherText);
105    return decryptData;
106  }
107  // 生成SM2密钥对
108  function genKeyPairByData(pubKeyData: Uint8Array, priKeyData: Uint8Array) {
109    let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyData };
110    let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyData };
111    let sm2Generator = cryptoFramework.createAsyKeyGenerator('SM2_256');
112    let keyPair = sm2Generator.convertKeySync(pubKeyBlob, priKeyBlob);
113    console.info('convertKeySync success');
114    return keyPair;
115  }
116  function main() {
117    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]);
118    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]);
119    let keyPair = genKeyPairByData(pkData, skData);
120    let pubKey = keyPair.pubKey;
121    let priKey = keyPair.priKey;
122    let message = 'This is a test';
123    // 把字符串按utf-8解码为Uint8Array
124    let plainText: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from(message, 'utf-8').buffer) };
125    let encryptText = encryptMessage(pubKey, plainText);
126    let decryptText = decryptMessage(priKey, encryptText);
127    if (plainText.data.toString() === decryptText.data.toString()) {
128      console.info('decrypt ok');
129      // 把Uint8Array按utf-8编码为字符串
130      let messageDecrypted = buffer.from(decryptText.data).toString('utf-8');
131      console.info('decrypted result string:' + messageDecrypted);
132    } else {
133      console.error('decrypt failed');
134    }
135  }
136  ```