Question

我对邮件进行加密，然后通过socket将其发送到其他计算机。但是我无法解密密文。我在两台计算机上使用了相同的密钥和iv。我尝试将密文发送到其他计算机，然后发回密文。我可以在同一台计算机上解密密文。但我想在其他计算机上将其删除。这是我的代码。

#include "cooloi_aes.h"

CooloiAES::CooloiAES(std::string aes_key)
{
    //key = (unsigned char*)"01234567890123456789012345678901";
    key = (unsigned char*)aes_key.c_str();
    iv = (unsigned char*)"aabbccddeeffgghh";
    ERR_load_crypto_strings();
    OpenSSL_add_all_algorithms();
    OPENSSL_config(NULL);
}

CooloiAES::~CooloiAES()
{

}

CooloiAES* CooloiAES::Create(std::string aes_key)
{
    auto ret = new CooloiAES(aes_key);
    return ret;
}

void CooloiAES::handleErrors(void)
{
    ERR_print_errors_fp(stderr);
    abort();
}

int CooloiAES::encrypt(unsigned char *plaintext, int plaintext_len,         unsigned char *key,
        unsigned char *iv, unsigned char *ciphertext)
{
    EVP_CIPHER_CTX *ctx;

    int len;

    int ciphertext_len;

// Create and initialise the context
if(!(ctx = EVP_CIPHER_CTX_new()))
    handleErrors();

// Initialise the encryption operation. IMPORTANT - ensure you use a key
// and IV size appropriate for your cipher
// In this example we are using 256 bit AES (i.e. a 256 bit key). The
// IV size for *most* modes is the same as the block size. For AES this
// is 128 bits
if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
    handleErrors();

// Provide the message to be encrypted, and obtain the encrypted output.
//  EVP_EncryptUpdate can be called multiple times if necessary
if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
    handleErrors();
ciphertext_len = len;

// Finalise the encryption. Further ciphertext bytes may be written at
//   this stage.
//   
if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len))
    handleErrors();
ciphertext_len += len;

// Clean up
EVP_CIPHER_CTX_free(ctx);

return ciphertext_len;
}

int CooloiAES::decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
        unsigned char *iv, unsigned char *plaintext)
{
    EVP_CIPHER_CTX *ctx;

int len;

int plaintext_len;

// Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new()))
    handleErrors();

// Initialise the decryption operation. IMPORTANT - ensure you use a key
// and IV size appropriate for your cipher
// In this example we are using 256 bit AES (i.e. a 256 bit key). The
// IV size for *most* modes is the same as the block size. For AES this
// is 128 bits
if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
    handleErrors();

// Provide the message to be decrypted, and obtain the plaintext output.
// EVP_DecryptUpdate can be called multiple times if necessary

if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
    handleErrors();
plaintext_len = len;

// Finalise the decryption. Further plaintext bytes may be written at
// this stage.

if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len))
    handleErrors();
plaintext_len += len;

// Clean up
EVP_CIPHER_CTX_free(ctx);

return plaintext_len;
}

std::string CooloiAES::aes_encrypt(std::string msg)
{
    int MSG_LEN = ((msg.size() / 16) + 1) * 16;
    unsigned char* plaintext = (unsigned char*)msg.c_str();

    unsigned char ciphertext[MSG_LEN];
    unsigned char decryptedtext[MSG_LEN];
    unsigned char cipher[MSG_LEN];

    int decryptedtext_len,ciphertext_len;
    ciphertext_len = encrypt(plaintext,strlen((char*)plaintext),key,iv,ciphertext);
    std::string str(ciphertext,ciphertext+ciphertext_len);
    return str; 
 }

 std::string CooloiAES::aes_decrypt(std::string msg)
 {
    int MSG_LEN = msg.size();
    //unsigned char* plaintext = (unsigned char*)msg.c_str();

    unsigned char ciphertext[MSG_LEN];
    unsigned char decryptedtext[MSG_LEN];
    unsigned char cipher[MSG_LEN];

    int decryptedtext_len,ciphertext_len;

    memcpy(cipher,msg.data(),msg.size());
    int len = sizeof(cipher);

    decryptedtext_len = decrypt(cipher,len,key,iv,decryptedtext);

    decryptedtext[decryptedtext_len] = '\0';

    std::string dec((char*)decryptedtext);
    return dec;
  }

我无法用AES-CBC解密密文

0 个答案: