C++ AES cbc加密 带iv向量 绝对可用

#include "aes_pack.h" #include <string.h> AesPack::AesPack() {} AesPack::~AesPack() {} int AesPack::encrypt(unsigned char *key, unsigned char *plaintext, const unsigned int plaintext_len, unsigned char *ciphertext, unsigned int *ciphertext_len) { EVP_CIPHER_CTX *ctx; unsigned int len; /* Create and initialise the context */ if (!(ctx = EVP_CIPHER_CTX_new())) goto end; /* 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, _mode, NULL, _key.data(), _iv.data())) goto end; /* 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, reinterpret_cast<int*>(&len), plaintext, plaintext_len)) goto end; *ciphertext_len = len; /* Finalise the encryption. Further ciphertext bytes may be written at * this stage. */ if (1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, reinterpret_cast<int*>(&len))) goto end; *ciphertext_len += len; /* Clean up */ if (ctx) EVP_CIPHER_CTX_free(ctx); return OK; end: ERR_print_errors_fp(stderr); /* Clean up */ if (ctx) EVP_CIPHER_CTX_free(ctx); return FAIL; } int AesPack::decrypt(unsigned char *key, unsigned char *ciphertext, const unsigned int ciphertext_len, unsigned char *plaintext, unsigned int *plaintext_len) { EVP_CIPHER_CTX *ctx; unsigned int len; /* Create and initialise the context */ if (!(ctx = EVP_CIPHER_CTX_new())) goto end; /* 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, _mode, NULL, _key.data(), _iv.data())) goto end; /* 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, reinterpret_cast<int*>(&len), ciphertext, ciphertext_len)) goto end; *plaintext_len = len; /* Finalise the decryption. Further plaintext bytes may be written at * this stage. */ if (1 != EVP_DecryptFinal_ex(ctx, plaintext + len, reinterpret_cast<int*>(&len))) goto end; *plaintext_len += len; /* Clean up */ EVP_CIPHER_CTX_free(ctx); return OK; end: ERR_print_errors_fp(stderr); /* Clean up */ if (ctx) EVP_CIPHER_CTX_free(ctx); return FAIL; } int main(void) { /* Set up the key and iv. Do I need to say to not hard code these in a * real application? :-) */ /* A 256 bit key */ //unsigned char *key = (unsigned char *)"673d9a02137ce81cbde3b98d87e41f42ce3e8a2633bd7741a6e21672b1da2104"; unsigned char key[]={0x67,0x3d,0x9a,0x02,0x13,0x7c,0xe8,0x1c,0xbd,0xe3,0xb9,0x8d,0x87,0xe4,0x1f,0x42,0xce,0x3e,0x8a,0x26,0x33,0xbd,0x77,0x41,0xa6,0xe2,0x16,0x72,0xb1,0xda,0x21,0x04}; /* A 128 bit IV */ //unsigned char *iv = (unsigned char *)"e488c61c6a93a87b9a7dfe29ae3c8c1a"; unsigned char iv[] = {0xe4,0x88,0xc6,0x1c,0x6a,0x93,0xa8,0x7b,0x9a,0x7d,0xfe,0x29,0xae,0x3c,0x8c,0x1a}; /* Message to be encrypted */ //const char *plaintext="Gwang**02"; unsigned char plaintext[]={0x47,0x77,0x61,0x6e,0x67,0x2a,0x2a,0x30,0x32}; /* Buffer for ciphertext. Ensure the buffer is long enough for the * ciphertext which may be longer than the plaintext, dependant on the * algorithm and mode */ unsigned char ciphertext[512]; /* Buffer for the decrypted text */ unsigned char decryptedtext[512]; unsigned int decryptedtext_len, ciphertext_len; AesPack aesPack; aesPack.setKey(key, 32); aesPack.setIV(iv, 16); aesPack.setMode(EVP_aes_256_cbc()); /* Encrypt the plaintext */ aesPack.encrypt(key, plaintext, sizeof(plaintext), ciphertext, &ciphertext_len); /* Do something useful with the ciphertext here */ printf("Ciphertext is:\n"); BIO_dump_fp(stdout, (const char *)ciphertext, ciphertext_len); /* Decrypt the ciphertext */ aesPack.decrypt(key, ciphertext, ciphertext_len, decryptedtext, &decryptedtext_len); /* Add a NULL terminator. We are expecting printable text */ decryptedtext[decryptedtext_len] = '\0'; /* Show the decrypted text */ printf("Decrypted text is:\n"); BIO_dump_fp(stdout, (const char *)decryptedtext, decryptedtext_len); if (!memcmp(&plaintext[0], &decryptedtext[0], sizeof(plaintext))) { printf("pass!\n"); } return 0; }