1# 使用AES对称密钥（ECB模式）加解密(C/C++)
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4对应的算法规格请查看[对称密钥加解密算法规格：AES](crypto-sym-encrypt-decrypt-spec.md#aes)。
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7## 在CMake脚本中链接相关动态库
8```txt
9   target_link_libraries(entry PUBLIC libohcrypto.so)
10```
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12## 开发步骤
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14**加密**
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171. 调用[OH_CryptoSymKeyGenerator_Create](../../reference/apis-crypto-architecture-kit/_crypto_sym_key_api.md#oh_cryptosymkeygenerator_create)、[OH_CryptoSymKeyGenerator_Generate](../../reference/apis-crypto-architecture-kit/_crypto_sym_key_api.md#oh_cryptosymkeygenerator_generate)，生成密钥算法为AES、密钥长度为128位的对称密钥（OH_CryptoSymKey）。
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19   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-ndk.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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212. 调用[OH_CryptoSymCipher_Create](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_create)，指定字符串参数'AES128|ECB|PKCS7'，创建对称密钥类型为AES128、分组模式为ECB、填充模式为PKCS7的Cipher实例，用于完成加解密操作。
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233. 调用[OH_CryptoSymCipher_Init](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_init)，设置模式为加密（CRYPTO_ENCRYPT_MODE），指定加密密钥（OH_CryptoSymKey），初始化加密Cipher实例。
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254. 加密内容较短时，可以不调用[OH_CryptoSymCipher_Update](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_update)，直接调用[OH_CryptoSymCipher_Final](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_final)，获取加密后的数据。
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275. 调用[OH_CryptoSymKeyGenerator_Destroy](../../reference/apis-crypto-architecture-kit/_crypto_sym_key_api.md#oh_cryptosymkeygenerator_destroy)、[OH_CryptoSymCipher_Destroy](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_destroy)销毁各对象。
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29**解密**
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321. 调用[OH_CryptoSymCipher_Init](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_init)，设置模式为解密（CRYPTO_DECRYPT_MODE），指定解密密钥（OH_CryptoSymKey）,初始化解密Cipher实例。
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342. 解密内容较短时，可以不调用[OH_CryptoSymCipher_Update](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_update)，直接调用[OH_CryptoSymCipher_Final](../../reference/apis-crypto-architecture-kit/_crypto_sym_cipher_api.md#oh_cryptosymcipher_final)，获取解密后的数据。
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38```c++
39#include "CryptoArchitectureKit/crypto_common.h"
40#include "CryptoArchitectureKit/crypto_sym_cipher.h"
41#include <string.h>
42
43static OH_Crypto_ErrCode doTestAesEcb()
44{
45    OH_CryptoSymKeyGenerator *genCtx = nullptr;
46    OH_CryptoSymCipher *encCtx = nullptr;
47    OH_CryptoSymCipher *decCtx = nullptr;
48    OH_CryptoSymKey *keyCtx = nullptr;
49    OH_CryptoSymCipherParams *params = nullptr;
50    char *plainText = const_cast<char *>("this is test");
51    Crypto_DataBlob input = {.data = (uint8_t *)(plainText), .len = strlen(plainText)};
52    Crypto_DataBlob outUpdate = {.data = nullptr, .len = 0};
53    Crypto_DataBlob decUpdate = {.data = nullptr, .len = 0};
54
55    // 随机生成对称密钥
56    OH_Crypto_ErrCode ret;
57    ret = OH_CryptoSymKeyGenerator_Create("AES128", &genCtx);
58    if (ret != CRYPTO_SUCCESS) {
59        goto end;
60    }
61    ret = OH_CryptoSymKeyGenerator_Generate(genCtx, &keyCtx);
62    if (ret != CRYPTO_SUCCESS) {
63        goto end;
64    }
65    // 创建参数
66    ret = OH_CryptoSymCipherParams_Create(&params);
67    if (ret != CRYPTO_SUCCESS) {
68        goto end;
69    }
70
71    // 加密操作
72    ret = OH_CryptoSymCipher_Create("AES128|ECB|PKCS7", &encCtx);
73    if (ret != CRYPTO_SUCCESS) {
74        goto end;
75    }
76    ret = OH_CryptoSymCipher_Init(encCtx, CRYPTO_ENCRYPT_MODE, keyCtx, params);
77    if (ret != CRYPTO_SUCCESS) {
78        goto end;
79    }
80    ret = OH_CryptoSymCipher_Final(encCtx, &input, &outUpdate);
81    if (ret != CRYPTO_SUCCESS) {
82        goto end;
83    }
84
85    // 解密操作
86    ret = OH_CryptoSymCipher_Create("AES128|ECB|PKCS7", &decCtx);
87    if (ret != CRYPTO_SUCCESS) {
88        goto end;
89    }
90    ret = OH_CryptoSymCipher_Init(decCtx, CRYPTO_DECRYPT_MODE, keyCtx, params);
91    if (ret != CRYPTO_SUCCESS) {
92        goto end;
93    }
94    ret = OH_CryptoSymCipher_Final(decCtx, &outUpdate, &decUpdate);
95    if (ret != CRYPTO_SUCCESS) {
96        goto end;
97    }
98
99end:
100    OH_CryptoSymCipherParams_Destroy(params);
101    OH_CryptoSymCipher_Destroy(encCtx);
102    OH_CryptoSymCipher_Destroy(decCtx);
103    OH_CryptoSymKeyGenerator_Destroy(genCtx);
104    OH_CryptoSymKey_Destroy(keyCtx);
105    OH_Crypto_FreeDataBlob(&outUpdate);
106    OH_Crypto_FreeDataBlob(&decUpdate);
107    return ret;
108}
109```
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