openssl的aes128_ECB加密解密运算实例

aes128算法ECB接口

加密接口

注意事项：

• EVP_EncryptInit_ex初始化算法EVP_aes_128_ecb()，和密钥，key至少16B
• EVP_EncryptUpdate加密运算，tmplen输出已加密长度
• EVP_EncryptFinal_ex结束运算，如果在此仍有加密运算，则加密长度tmplen需补充到密文长度中

int openssl_aes128_encrypt_ecb(unsigned char *key,unsigned char *iv, unsigned char *in_buf, int in_len, unsigned char *out_buf,int* out_len)
{EVP_CIPHER_CTX* ctx = NULL;ctx = EVP_CIPHER_CTX_new();int tmplen = 0;printf("%s %d\n", __func__, __LINE__);EVP_EncryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, key, NULL);if (!EVP_EncryptUpdate(ctx, out_buf, &tmplen, in_buf, in_len)){EVP_CIPHER_CTX_free(ctx);return -1;}*out_len = tmplen;if (!EVP_EncryptFinal_ex(ctx, out_buf + *out_len, &tmplen)){EVP_CIPHER_CTX_free(ctx);return -2;}*out_len += tmplen;EVP_CIPHER_CTX_free(ctx);return 0 ;
}

解密接口

注意事项：

• EVP_DecryptInit_ex初始化算法EVP_aes_128_ecb()，和密钥，key至少16B
• EVP_DecryptUpdate解密运算，tmplen输出已解密长度
• 如果剩余字节是16B，再次使用EVP_DecryptUpdate
• 如果剩余字节不是16B整数倍，使用EVP_EncryptFinal_ex结束运算，输出加密长度tmplen补充到密文长度中

int openssl_aes128_decrypt_ecb(unsigned char *key,unsigned char *iv, unsigned char *in_buf, int in_len, unsigned char *out_buf,int* out_len)
{int ret = 0 ,tmplen = 0;EVP_CIPHER_CTX* ctx = NULL;ctx = EVP_CIPHER_CTX_new();EVP_CIPHER_CTX_set_padding(ctx, 0);printf("%s %d\n", __func__, __LINE__);EVP_DecryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, key, NULL);if (!EVP_DecryptUpdate(ctx, out_buf, &tmplen, in_buf, in_len)){EVP_CIPHER_CTX_free(ctx);return -1;}*out_len = tmplen;if (in_len > tmplen) {if (!EVP_DecryptUpdate(ctx, out_buf+tmplen, &tmplen, in_buf+tmplen, in_len-tmplen)){//        RSP_TRACE("%s EVP_DecryptUpdate error \n", __func__);EVP_CIPHER_CTX_free(ctx);return -1;}*out_len += tmplen;}if (in_len %16!=0){ret = EVP_DecryptFinal_ex(ctx, out_buf+tmplen, &tmplen);fprintf(stderr, "err:\n");if (ret != 0){//        RSP_TRACE("%s EVP_DecryptFinal_ex error ret=%d\n", __func__, ret);EVP_CIPHER_CTX_free(ctx);return -2;}*out_len += tmplen;}EVP_CIPHER_CTX_free(ctx);return 0 ;
}