正如您所说,主要问题在于您的 encrypt() 函数,而且还在于您如何调用它。您正在使用 malloc() 在函数内分配内存,并且从不释放它,这是内存泄漏(无论如何 malloc 在 c++ 中都是禁忌)。您也没有为您的 ctx 运行清理功能。并且您的 encrypt_final 正在覆盖输出缓冲区的第一部分。因此,这是一个清理后的 encrypt() 和一个匹配的解密():
int encrypt(unsigned char *key,
unsigned char *iv,
unsigned char * source,
unsigned char* target,
int in_len) // Need an in length. Not all input is going to be
// zero-terminated, for example if we're reading from a file
{
int out_len; // Return the output length. Because it also won't be null
// terminated, and may contain null characters inline
int final_out_len; // So that we don't overwrite out_len with the final call
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx);
EVP_EncryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,key,iv);
EVP_EncryptUpdate(&ctx,target,&out_len,source,in_len);
EVP_EncryptFinal_ex(&ctx,target+out_len,&final_out_len);
EVP_CIPHER_CTX_cleanup(&ctx);
return out_len+final_out_len; // need to sum these together, because both
// encrypt calls wrote data
}
并解密:
int decrypt(unsigned char *key,
unsigned char *iv,
unsigned char * source,
unsigned char* target,
int in_len)
{
int out_len=0,final_out_len=0;
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx);
EVP_DecryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,key,iv);
EVP_DecryptUpdate(&ctx,target,&out_len,source,in_len);
EVP_DecryptFinal_ex(&ctx,target+out_len,&final_out_len);
EVP_CIPHER_CTX_cleanup(&ctx);
//Just to be nice, we'll add a zero at the end of the decrypted string
target[out_len+final_out_len] = 0;
return out_len+final_out_len;
}
将它们放在一起(循环,以证明你的概念):
int _tmain(int argc, _TCHAR* argv[])
{
unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
unsigned char ivec[] = {1,2,3,4,5,6,7,8};
char *raw_buffer = "This is a test string";
int raw_count = strlen(raw_buffer);
for (int i=0; i<5; i++){
unsigned char *decrypted_buffer = new unsigned char[raw_count+64];
unsigned char *encrypted_buffer = new unsigned char[raw_count+64];
int final_len = encrypt(key,ivec,(unsigned char*)raw_buffer,(unsigned char*)encrypted_buffer,raw_count);
int dec_len = decrypt(key,ivec,(unsigned char*)encrypted_buffer,(unsigned char*)decrypted_buffer,final_len);
printf("raw_count: %i\nfinal_len: %i\ndec_len: %i\n",raw_count,final_len,dec_len);
printf("Original str: \n%s\n",raw_buffer);
printf("Encrypted: \n%s\n", encrypted_buffer);
printf("Decrypted:\n%s\n\n\n", decrypted_buffer);
delete[] decrypted_buffer;
delete[] encrypted_buffer;
}
char c;
c=getchar();
return 0;
}