C++ AES CBC 加密 代码 使用 openssl

在C++中使用OpenSSL库进行AES加密，特别是CBC模式，你需要包括相关的头文件并初始化OpenSSL库。以下是一个简单的示例，展示了如何对数据进行AES-CBC加密和解密：

#include <openssl/aes.h>
#include <openssl/evp.h>
#include <string>

std::string encrypt_CBC(const std::string& plaintext, const std::string& key, const std::string& iv) {
    AES_KEY aes_key;
    unsigned char iv_bytes[AES_BLOCK_SIZE];
    memcpy(iv_bytes, iv.c_str(), AES_BLOCK_SIZE);

    // Initialize the AES key
    if (AES_set_encrypt_key((unsigned char*)key.c_str(), key.length() * 8, &aes_key) != AES_SUCCESS) {
        throw std::runtime_error("AES key initialization failed");
    }

    // Create a buffer for the ciphertext and initialize it with the IV
    size_t ciphertext_len = plaintext.length() + AES_BLOCK_SIZE;
    unsigned char* ciphertext = new unsigned char[ciphertext_len];
    memcpy(ciphertext, iv_bytes, AES_BLOCK_SIZE); // Add the IV at the beginning

    // Encrypt the plaintext in CBC mode
    size_t blocks = plaintext.length() / AES_BLOCK_SIZE;
    for (size_t i = 0; i < blocks; ++i) {
        AES_cbc_encrypt(reinterpret_cast<const unsigned char*>(plaintext.data() + i * AES_BLOCK_SIZE), ciphertext + i * AES_BLOCK_SIZE, AES_BLOCK_SIZE, &aes_key, iv_bytes, AES_ENCRYPT);
    }
    if (plaintext.length() % AES_BLOCK_SIZE > 0) { // Padding for last block
        AES_cbc_encrypt(reinterpret_cast<const unsigned char*>(plaintext.data() + blocks * AES_BLOCK_SIZE), ciphertext + blocks * AES_BLOCK_SIZE, plaintext.length() % AES_BLOCK_SIZE, &aes_key, iv_bytes, AES_ENCRYPT);
    }

    std::string encrypted_text(reinterpret_cast<char*>(ciphertext), ciphertext_len - AES_BLOCK_SIZE);
    delete[] ciphertext;
    return encrypted_text;
}

std::string decrypt_CBC(const std::string& ciphertext, const std::string& key, const std::string& iv) {
    // Similar to encrypt function, but use AES_decrypt instead of AES_encrypt
    // Remember to properly handle padding when decrypting
    // ...
}

int main() {
    try {
        std::string plaintext = "This is a secret message";
        std::string key = "mysecretkey1234567890123456"; // 256-bit key
        std::string iv = "0123456789abcdef01234567"; // 16-byte initialization vector

        std::string encrypted = encrypt_CBC(plaintext, key, iv);
        std::string decrypted = decrypt_CBC(encrypted, key, iv);

        if (decrypted == plaintext) {
            std::cout << "Encryption and decryption successful!" << std::endl;
        } else {
            std::cerr << "Decryption failed!" << std::endl;
        }
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }
    return 0;
}

请注意，上述代码仅作为一个基本示例，并未包含完整的错误处理和padding处理。实际应用中，你需要确保IV的安全性和正确的填充。在`decrypt_CBC`函数中，你需要根据OpenSSL文档调整处理方式。