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1# 使用RSA非对称密钥（PKCS1模式）加解密(C/C++)
2
3<!--Kit: Crypto Architecture Kit-->
4<!--Subsystem: Security-->
5<!--Owner: @zxz--3-->
6<!--Designer: @lanming-->
7<!--Tester: @PAFT-->
8<!--Adviser: @zengyawen-->
9
10对应的算法规格请查看[非对称密钥加解密算法规格：RSA](crypto-asym-encrypt-decrypt-spec.md#rsa)。
11
12**加密**
13
141. 调用[OH_CryptoAsymKeyGenerator_Create](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-key-h.md#oh_cryptoasymkeygenerator_create)、[OH_CryptoAsymKeyGenerator_Generate](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-key-h.md#oh_cryptoasymkeygenerator_generate)，生成RSA密钥类型为RSA1024、素数个数为2的非对称密钥对（keyPair）。keyPair对象中包括公钥PubKey、私钥PriKey。
15
16   如何生成RSA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：RSA](crypto-asym-key-generation-conversion-spec.md#rsa)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。
17
182. 调用[OH_CryptoAsymCipher_Create](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_create)，指定字符串参数'RSA1024|PKCS1'，创建非对称密钥类型为RSA1024、填充模式为PKCS1的Cipher实例，用于完成加解密操作。
19
203. 调用[OH_CryptoAsymCipher_Init](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_init)，设置模式为加密（CRYPTO_ENCRYPT_MODE），指定加密密钥（keyPair），初始化加密Cipher实例。
21
224. 调用[OH_CryptoAsymCipher_Final](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_final)，传入明文，获取加密后的数据。
23
24   - OH_CryptoAsymCipher_Final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。
25   - 当数据量较大时，可以多次调用OH_CryptoAsymCipher_Final，即[分段加解密](crypto-rsa-asym-encrypt-decrypt-by-segment-ndk.md)。
26
27**解密**
28
291. 由于RSA算法的Cipher实例不支持重复init操作，需要调用[OH_CryptoAsymCipher_Create](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_create)，重新生成Cipher实例。
30
312. 调用[OH_CryptoAsymCipher_Init](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_init)，设置模式为解密（CRYPTO_DECRYPT_MODE），指定解密密钥（keyPair）初始化解密Cipher实例。
32
333. 调用[OH_CryptoAsymCipher_Final](../../reference/apis-crypto-architecture-kit/capi-crypto-asym-cipher-h.md#oh_cryptoasymcipher_final)，传入密文，获取解密后的数据。
34
35```C++
36#include "CryptoArchitectureKit/crypto_architecture_kit.h"
37#include <string.h>
38
39static OH_Crypto_ErrCode doTestRsaEncDec()
40{
41    OH_CryptoAsymKeyGenerator *keyGen = nullptr;
42    OH_Crypto_ErrCode ret = OH_CryptoAsymKeyGenerator_Create("RSA1024", &keyGen);
43    if (ret != CRYPTO_SUCCESS) {
44        return ret;
45    }
46
47    OH_CryptoKeyPair *keyPair = nullptr;
48    ret = OH_CryptoAsymKeyGenerator_Generate(keyGen, &keyPair);
49    if (ret != CRYPTO_SUCCESS) {
50        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
51        return ret;
52    }
53
54    OH_CryptoAsymCipher *cipher = nullptr;
55    ret = OH_CryptoAsymCipher_Create("RSA1024|PKCS1", &cipher);
56    if (ret != CRYPTO_SUCCESS) {
57        OH_CryptoKeyPair_Destroy(keyPair);
58        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
59        return ret;
60    }
61
62    ret = OH_CryptoAsymCipher_Init(cipher, CRYPTO_ENCRYPT_MODE, keyPair);
63    if (ret != CRYPTO_SUCCESS) {
64        OH_CryptoAsymCipher_Destroy(cipher);
65        OH_CryptoKeyPair_Destroy(keyPair);
66        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
67        return ret;
68    }
69
70    const char *testData = "Hello, RSA!";
71    Crypto_DataBlob in = {
72        .data = (uint8_t *)testData,
73        .len = strlen(testData)
74    };
75
76    Crypto_DataBlob out = { 0 };
77    ret = OH_CryptoAsymCipher_Final(cipher, &in, &out);
78    if (ret != CRYPTO_SUCCESS) {
79        OH_CryptoAsymCipher_Destroy(cipher);
80        OH_CryptoKeyPair_Destroy(keyPair);
81        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
82        return ret;
83    }
84
85    OH_CryptoAsymCipher_Destroy(cipher);
86    cipher = nullptr;
87    ret = OH_CryptoAsymCipher_Create("RSA1024|PKCS1", &cipher);
88    if (ret != CRYPTO_SUCCESS) {
89        OH_Crypto_FreeDataBlob(&out);
90        OH_CryptoKeyPair_Destroy(keyPair);
91        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
92        return ret;
93    }
94
95    ret = OH_CryptoAsymCipher_Init(cipher, CRYPTO_DECRYPT_MODE, keyPair);
96    if (ret != CRYPTO_SUCCESS) {
97        OH_CryptoAsymCipher_Destroy(cipher);
98        OH_Crypto_FreeDataBlob(&out);
99        OH_CryptoKeyPair_Destroy(keyPair);
100        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
101        return ret;
102    }
103    Crypto_DataBlob decrypted = { 0 };
104    ret = OH_CryptoAsymCipher_Final(cipher, &out, &decrypted);
105    if (ret != CRYPTO_SUCCESS) {
106        OH_CryptoAsymCipher_Destroy(cipher);
107        OH_Crypto_FreeDataBlob(&out);
108        OH_CryptoKeyPair_Destroy(keyPair);
109        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
110        return ret;
111    }
112    if ((decrypted.len != strlen(testData)) || (memcmp(decrypted.data, testData, decrypted.len) != 0)) {
113        OH_Crypto_FreeDataBlob(&decrypted);
114        OH_CryptoAsymCipher_Destroy(cipher);
115        OH_Crypto_FreeDataBlob(&out);
116        OH_CryptoKeyPair_Destroy(keyPair);
117        OH_CryptoAsymKeyGenerator_Destroy(keyGen);
118        return CRYPTO_OPERTION_ERROR;
119    }
120
121    OH_Crypto_FreeDataBlob(&decrypted);
122    OH_CryptoAsymCipher_Destroy(cipher);
123    OH_Crypto_FreeDataBlob(&out);
124    OH_CryptoKeyPair_Destroy(keyPair);
125    OH_CryptoAsymKeyGenerator_Destroy(keyGen);
126    return ret;
127}
128```