1# 使用SM2密钥对验签(C/C++)
2
3
4对应的算法规格请查看[验签算法规格：SM2](crypto-sign-sig-verify-overview.md#sm2)。
5
6
7## 在CMake脚本中链接相关动态库
8```txt
9   target_link_libraries(entry PUBLIC libohcrypto.so)
10```
11
12## 开发步骤
13
14
151. 调用[OH_CryptoVerify_Create](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_create)，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Verify实例，用于完成验签操作。
16
172. 调用[OH_CryptoVerify_Init](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_init)，使用公钥（OH_CryptoPubKey）初始化Verify实例。
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193. 调用[OH_CryptoVerify_Update](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_update)，传入待验证的数据。
20   当前单次update长度没有限制，开发者可以根据数据量判断如何调用update，如果数据量较小，可以直接调用OH_CryptoVerify_Final接口一次性传入。
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224. 调用[OH_CryptoVerify_Final](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_final)，对数据进行验签。
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25
26```c++
27#include "CryptoArchitectureKit/crypto_common.h"
28#include "CryptoArchitectureKit/crypto_signature.h"
29#include "CryptoArchitectureKit/crypto_asym_key.h"
30
31static bool doTestSm2Signature()
32{
33   OH_CryptoAsymKeyGenerator *keyCtx = nullptr;
34   OH_CryptoKeyPair *keyPair = nullptr;
35   OH_CryptoVerify *verify = nullptr;
36
37   uint8_t plainText[] = {
38      0x96, 0x46, 0x2e, 0xde, 0x3f, 0x47, 0xbf, 0xd6, 0x87, 0x48, 0x36, 0x1d, 0x75, 0x35, 0xbd, 0xbc,
39      0x6b, 0x06, 0xe8, 0xb3, 0x68, 0x91, 0x53, 0xce, 0x76, 0x5d, 0x24, 0xda, 0xdc, 0xc4, 0x9f, 0x94,
40   };
41   Crypto_DataBlob msgBlob = {
42      .data = reinterpret_cast<uint8_t *>(plainText),
43      .len = sizeof(plainText)
44   };
45
46   uint8_t pubKeyText[] = {
47      0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01, 0x06, 0x08, 0x2a,
48      0x81, 0x1c, 0xcf, 0x55, 0x01, 0x82, 0x2d, 0x03, 0x42, 0x00, 0x04, 0x80, 0x5b, 0x78, 0x04, 0xd7,
49      0xcf, 0xc3, 0x99, 0x63, 0xae, 0x88, 0xcd, 0xfc, 0xd6, 0x18, 0xf4, 0x08, 0xe8, 0xe3, 0x68, 0x47,
50      0x4f, 0x44, 0x0e, 0xb2, 0xba, 0x3a, 0xb3, 0x10, 0xf1, 0xc9, 0xd0, 0x84, 0xe2, 0xa4, 0x47, 0xbe,
51      0x72, 0xae, 0xf8, 0x6a, 0xeb, 0x6e, 0x10, 0xab, 0x52, 0x6b, 0x6a, 0x58, 0xc6, 0xb5, 0x78, 0xaa,
52      0x70, 0xe5, 0x58, 0x20, 0x4e, 0x34, 0x42, 0x77, 0x08, 0x27, 0x11,
53   };
54
55   Crypto_DataBlob keyBlob = {
56      .data = reinterpret_cast<uint8_t *>(pubKeyText),
57      .len = sizeof(pubKeyText)
58   };
59
60   uint8_t signText[] = {
61      0x30, 0x45, 0x02, 0x21, 0x00, 0xf4, 0xe7, 0x9d, 0x35, 0x33, 0xa6, 0x86, 0x2e, 0x2a, 0x97, 0x72,
62      0xc9, 0x46, 0x79, 0x65, 0xca, 0x4a, 0x71, 0x34, 0xca, 0xf7, 0x58, 0xb3, 0x26, 0xa5, 0xdb, 0xfa,
63      0x8b, 0xbe, 0xbf, 0x5f, 0x90, 0x02, 0x20, 0x53, 0xb4, 0x23, 0xb1, 0xe2, 0x8f, 0x2f, 0xe9, 0xc8,
64      0x22, 0xef, 0xab, 0x9b, 0x13, 0x08, 0x75, 0x8e, 0xb1, 0x9c, 0x59, 0xe5, 0xd6, 0x64, 0x35, 0xf5,
65      0xd1, 0xde, 0xfa, 0xfe, 0x80, 0x37, 0x1a,
66   };
67
68   Crypto_DataBlob signBlob = {
69      .data = reinterpret_cast<uint8_t *>(signText),
70      .len = sizeof(signText)
71   };
72
73   // keypair
74   OH_Crypto_ErrCode ret = CRYPTO_SUCCESS;
75   ret = OH_CryptoAsymKeyGenerator_Create((const char *)"SM2_256", &keyCtx);
76   if (ret != CRYPTO_SUCCESS) {
77      return false;
78   }
79   ret = OH_CryptoAsymKeyGenerator_Convert(keyCtx, CRYPTO_DER, &keyBlob, nullptr, &keyPair);
80   if (ret != CRYPTO_SUCCESS) {
81      OH_CryptoAsymKeyGenerator_Destroy(keyCtx);
82      return false;
83   }
84   OH_CryptoPubKey *pubKey = OH_CryptoKeyPair_GetPubKey(keyPair);
85   // verify
86   ret = OH_CryptoVerify_Create((const char *)"SM2_256|SM3", &verify);
87   if (ret != CRYPTO_SUCCESS) {
88      OH_CryptoVerify_Destroy(verify);
89      OH_CryptoAsymKeyGenerator_Destroy(keyCtx);
90      return false;
91   }
92   ret = OH_CryptoVerify_Init(verify, pubKey);
93   if (ret != CRYPTO_SUCCESS) {
94      OH_CryptoVerify_Destroy(verify);
95      OH_CryptoAsymKeyGenerator_Destroy(keyCtx);
96      return false;
97   }
98   bool res = OH_CryptoVerify_Final(verify, &msgBlob, &signBlob);
99   if (res != true) {
100      OH_CryptoVerify_Destroy(verify);
101      OH_CryptoAsymKeyGenerator_Destroy(keyCtx);
102      return false;
103   }
104
105   OH_CryptoVerify_Destroy(verify);
106   OH_CryptoAsymKeyGenerator_Destroy(keyCtx);
107   OH_CryptoKeyPair_Destroy(keyPair);
108   return res;
109}
110  ```
111