1# Signing and Signature Verification by Segment with an RSA Key Pair (PKCS1 Mode) (C/C++) 2 3 4For details about the algorithm specifications, see [RSA](crypto-sign-sig-verify-overview.md#rsa). 5 6 7## Adding the Dynamic Library in the CMake Script 8```txt 9target_link_libraries(entry PUBLIC libohcrypto.so) 10``` 11 12## How to Develop 13 14 151. Call [OH_CryptoVerify_Create](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_create) with the string parameter **'RSA1024|PKCS1|SHA256'** to create a **Verify** instance. The string parameter must be the same as that used to create the **Sign** instance. 16 172. Call [OH_CryptoVerify_Init](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_init) to initialize the **Verify** instance by using the public key (**OH_CryptoPubKey**). 18 193. Call [OH_CryptoVerify_Update](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_update) to pass in the data to be verified. 20 21 Currently, the amount of data to be passed in by a single **OH_CryptoVerify_Update** is not limited. You can determine how to pass in data based on the data volume. If a small amount of data is to be verified, you can call **OH_CryptoVerify_Final** immediately after **OH_CryptoVerify_Init()**. 22 234. Call [OH_CryptoVerify_Final](../../reference/apis-crypto-architecture-kit/_crypto_signature_api.md#oh_cryptoverify_final) to verify the signature. 24 25 26**Example** 27 28```c++ 29#include "CryptoArchitectureKit/crypto_common.h" 30#include "CryptoArchitectureKit/crypto_asym_key.h" 31#include "CryptoArchitectureKit/crypto_signature.h" 32 33static bool doTestRsaSignatureSeg() 34{ 35 OH_CryptoAsymKeyGenerator *keyCtx = nullptr; 36 OH_CryptoKeyPair *keyPair = nullptr; 37 OH_CryptoVerify *verify = nullptr; 38 39 uint8_t plainText[] = { 40 0x43, 0x31, 0x7d, 0xb5, 0x85, 0x2e, 0xd4, 0xef, 0x08, 0x7a, 0x17, 0x96, 0xbc, 0x7c, 0x8f, 0x80, 41 0x8c, 0xa7, 0x63, 0x7f, 0x26, 0x89, 0x8f, 0xf0, 0xfa, 0xa7, 0x51, 0xbd, 0x9c, 0x69, 0x17, 0xf3, 42 0xd1, 0xb5, 0xc7, 0x12, 0xbf, 0xcf, 0x91, 0x25, 0x82, 0x23, 0x6b, 0xd6, 0x64, 0x52, 0x77, 0x93, 43 0x01, 0x9d, 0x70, 0xa3, 0xf4, 0x92, 0x16, 0xec, 0x3f, 0xa7, 0x3c, 0x83, 0x8d, 0x40, 0x41, 0xfc, 44 }; 45 Crypto_DataBlob msgBlob = { 46 .data = reinterpret_cast<uint8_t *>(plainText), 47 .len = sizeof(plainText) 48 }; 49 50 uint8_t pubKeyText[] = { 51 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x42, 0x45, 0x47, 0x49, 0x4e, 0x20, 0x52, 0x53, 0x41, 0x20, 0x50, 52 0x55, 0x42, 0x4c, 0x49, 0x43, 0x20, 0x4b, 0x45, 0x59, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x0a, 0x4d, 53 0x49, 0x47, 0x4a, 0x41, 0x6f, 0x47, 0x42, 0x41, 0x4d, 0x78, 0x63, 0x44, 0x4d, 0x6f, 0x61, 0x59, 54 0x52, 0x58, 0x6f, 0x78, 0x65, 0x69, 0x33, 0x49, 0x6d, 0x33, 0x33, 0x78, 0x4a, 0x76, 0x61, 0x73, 55 0x63, 0x43, 0x62, 0x77, 0x31, 0x6f, 0x73, 0x63, 0x32, 0x56, 0x56, 0x69, 0x47, 0x6a, 0x56, 0x47, 56 0x47, 0x4a, 0x37, 0x6c, 0x75, 0x4e, 0x41, 0x58, 0x6b, 0x6a, 0x73, 0x56, 0x46, 0x64, 0x35, 0x0a, 57 0x58, 0x37, 0x4c, 0x4d, 0x6c, 0x46, 0x34, 0x63, 0x35, 0x5a, 0x75, 0x59, 0x2f, 0x61, 0x69, 0x57, 58 0x77, 0x70, 0x54, 0x69, 0x63, 0x62, 0x67, 0x49, 0x33, 0x43, 0x66, 0x50, 0x6f, 0x32, 0x6a, 0x6c, 59 0x52, 0x74, 0x67, 0x41, 0x46, 0x6b, 0x44, 0x71, 0x7a, 0x4b, 0x53, 0x46, 0x62, 0x46, 0x47, 0x51, 60 0x6b, 0x43, 0x6e, 0x64, 0x63, 0x2b, 0x54, 0x59, 0x6b, 0x5a, 0x42, 0x32, 0x70, 0x45, 0x6f, 0x72, 61 0x0a, 0x7a, 0x73, 0x61, 0x56, 0x58, 0x77, 0x5a, 0x47, 0x45, 0x34, 0x41, 0x43, 0x70, 0x59, 0x35, 62 0x79, 0x65, 0x66, 0x49, 0x44, 0x6c, 0x45, 0x57, 0x49, 0x51, 0x4f, 0x6a, 0x59, 0x4b, 0x2f, 0x6c, 63 0x58, 0x71, 0x7a, 0x48, 0x47, 0x69, 0x4f, 0x69, 0x32, 0x75, 0x4a, 0x45, 0x75, 0x44, 0x43, 0x50, 64 0x6a, 0x51, 0x64, 0x6a, 0x54, 0x41, 0x67, 0x4d, 0x42, 0x41, 0x41, 0x45, 0x3d, 0x0a, 0x2d, 0x2d, 65 0x2d, 0x2d, 0x2d, 0x45, 0x4e, 0x44, 0x20, 0x52, 0x53, 0x41, 0x20, 0x50, 0x55, 0x42, 0x4c, 0x49, 66 0x43, 0x20, 0x4b, 0x45, 0x59, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x0a, 67 }; 68 69 Crypto_DataBlob keyBlob = { 70 .data = reinterpret_cast<uint8_t *>(pubKeyText), 71 .len = sizeof(pubKeyText) 72 }; 73 74 uint8_t signText[] = { 75 0x68, 0x2f, 0x3b, 0xe6, 0xa6, 0x5c, 0xb8, 0x60, 0xd4, 0xe1, 0x64, 0xa7, 0xd8, 0x0c, 0x9c, 0x89, 76 0x39, 0xb4, 0xf0, 0xb7, 0xad, 0xb5, 0x8a, 0x71, 0x04, 0xf1, 0xa5, 0x63, 0xdd, 0x32, 0x6a, 0x44, 77 0xeb, 0xff, 0xb7, 0xe6, 0x85, 0xe5, 0xa5, 0x55, 0x5d, 0x5b, 0x28, 0x53, 0x63, 0xe4, 0xb3, 0xb9, 78 0xa8, 0x70, 0xc8, 0x8f, 0xcd, 0x21, 0x8d, 0xe6, 0x1f, 0xe5, 0x78, 0x34, 0xd3, 0x45, 0x0c, 0x9c, 79 0x7a, 0x22, 0x1b, 0x63, 0x55, 0xca, 0x14, 0xa5, 0x0c, 0x7a, 0x40, 0x8e, 0xa1, 0x14, 0x78, 0xa1, 80 0xf1, 0x36, 0x78, 0xbd, 0xba, 0x37, 0x3b, 0x5b, 0xb0, 0x8e, 0xb3, 0x4a, 0x9b, 0x1b, 0x0c, 0xfa, 81 0xfa, 0xc7, 0x9f, 0xb1, 0x35, 0x48, 0x82, 0x73, 0xf8, 0x6b, 0xd4, 0x76, 0x33, 0x5c, 0xed, 0x9c, 82 0xd8, 0x4b, 0xc9, 0x92, 0xa0, 0x3f, 0x6e, 0xba, 0x78, 0x2e, 0x80, 0x78, 0x1e, 0x74, 0xa0, 0x47, 83 }; 84 85 Crypto_DataBlob signBlob = { 86 .data = reinterpret_cast<uint8_t *>(signText), 87 .len = sizeof(signText) 88 }; 89 90 // keypair 91 OH_Crypto_ErrCode ret = CRYPTO_SUCCESS; 92 ret = OH_CryptoAsymKeyGenerator_Create((const char *)"RSA2048", &keyCtx); 93 if (ret != CRYPTO_SUCCESS) { 94 return false; 95 } 96 ret = OH_CryptoAsymKeyGenerator_Convert(keyCtx, CRYPTO_PEM, &keyBlob, nullptr, &keyPair); 97 if (ret != CRYPTO_SUCCESS) { 98 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 99 return false; 100 } 101 OH_CryptoPubKey *pubKey = OH_CryptoKeyPair_GetPubKey(keyPair); 102 // verify 103 ret = OH_CryptoVerify_Create((const char *)"RSA1024|PKCS1|SHA256", &verify); 104 if (ret != CRYPTO_SUCCESS) { 105 OH_CryptoVerify_Destroy(verify); 106 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 107 return false; 108 } 109 int blockSize = 20; 110 int cnt_s = 64 / blockSize; 111 int rem_s = 64 % blockSize; 112 ret = OH_CryptoVerify_Init(verify, pubKey); 113 if (ret != CRYPTO_SUCCESS) { 114 OH_CryptoVerify_Destroy(verify); 115 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 116 return false; 117 } 118 for (int i = 0; i < cnt_s; i++) { 119 msgBlob.len = blockSize; 120 ret = OH_CryptoVerify_Update(verify, (Crypto_DataBlob *)&msgBlob); 121 if (ret != CRYPTO_SUCCESS) { 122 OH_CryptoVerify_Destroy(verify); 123 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 124 return false; 125 } 126 msgBlob.data += blockSize; 127 } 128 bool res = false; 129 if (rem_s > 0) { 130 msgBlob.len = rem_s; 131 res = OH_CryptoVerify_Final(verify, (Crypto_DataBlob *)&msgBlob, (Crypto_DataBlob *)&signBlob); 132 if (res != true) { 133 OH_CryptoVerify_Destroy(verify); 134 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 135 return false; 136 } 137 } 138 139 msgBlob.data -= 64 - rem_s; 140 msgBlob.len = 64; 141 142 OH_CryptoVerify_Destroy(verify); 143 OH_CryptoAsymKeyGenerator_Destroy(keyCtx); 144 OH_CryptoKeyPair_Destroy(keyPair); 145 return res; 146} 147``` 148