自学教程：C++ AES_cbc_encrypt函数代码示例

uint8_t *aos_cipher_decrypt(struct aos_encryption *enc, const uint8_t *in, unsigned int length){	uint8_t *decrypted;	unsigned int done = 0;		decrypted = (uint8_t *)malloc(length);	if(!decrypted)		return NULL;		while(done < length) {		uint8_t iv[AES_BLOCK_SIZE];		uint8_t data[AES_BLOCK_SIZE];		struct aos_block *block = (struct aos_block *)&data;				memcpy(iv, enc->iv, AES_BLOCK_SIZE);				AES_cbc_encrypt(&in[done], data, AES_BLOCK_SIZE, &enc->key, iv, AES_DECRYPT);		memcpy(&decrypted[done], &data, AES_BLOCK_SIZE);		done += AES_BLOCK_SIZE;				AES_cbc_encrypt(&in[done], &decrypted[done], block->length-AES_BLOCK_SIZE, &enc->key, iv, AES_DECRYPT);		done += block->length-AES_BLOCK_SIZE;	}		return decrypted;}

static int blockchain_decrypt(unsigned char *derived_key, unsigned char *data){	unsigned char out[SAFETY_FACTOR];	AES_KEY akey;	unsigned char iv[16];	memcpy(iv, cur_salt->data, 16);	if(AES_set_decrypt_key(derived_key, 256, &akey) < 0) {		fprintf(stderr, "AES_set_decrypt_key failed in crypt!/n");	}	AES_cbc_encrypt(data + 16, out, 16, &akey, iv, AES_DECRYPT);	/* various tests */	if (out[0] != '{') // fast test		return -1;	// "guid" will be found in the first block	if (memmem(out, 16, "/"guid/"", 6)) {		memcpy(iv, cur_salt->data, 16); //IV has to be reset.		AES_cbc_encrypt(data + 16, out, SAFETY_FACTOR, &akey, iv, AES_DECRYPT);		if (memmem(out, SAFETY_FACTOR, "/"sharedKey/"", 11) &&			memmem(out, SAFETY_FACTOR, "/"options/"", 9))			// Note, we 'could' check that the guid and sharedKey values are			// 'valid' GUID's, but there really is no point. We already have			// 2^216 confidence in the simple text strings being found.			return 0;	}	return -1;}

int aes_encrypt(void *in, size_t len, unsigned char **out, unsigned char *iv, unsigned char *key){    AES_KEY aeskey;    int ret;    if (!len)        return 0;    ret = AES_set_encrypt_key(key, 256, &aeskey);    assert(!ret);    printf("(len: %ld pad: %ld)/n", len, len % 16);    len += len % 16;    *out = calloc(1, len); // consider padding..    assert(*out);#ifdef SKIP_LAST_WORD    AES_cbc_encrypt(in, *out, len-4, &aeskey, iv, AES_ENCRYPT);     memcpy(*out + (len - 4), in + (len - 4), 4);#else    AES_cbc_encrypt(in, *out, len, &aeskey, iv, AES_ENCRYPT); #endif    printf("/nplaintext (excerpt):/n");    print_hex(in, 128, 0);    printf("ciphertext (excerpt):/n");    print_hex(*out, 128, 0);    return 0;}

// main entrypointint main(int argc, char **argv){    int keylength;    printf("Give a key length [only 128 or 192 or 256!]:/n");    scanf("%d", &keylength);    /* generate a key with a given length */    unsigned char aes_key[keylength/8];    memset(aes_key, 0, keylength/8);    if (!RAND_bytes(aes_key, keylength/8))        exit(-1);    /* input struct creation */    size_t inputslength = sizeof(USR_TICKET);    USR_TICKET ticket;    ticket.ticketId = 1;    time_t now = time(NULL);    strftime(ticket.date, 20, "%Y-%m-%d", localtime(&now));    strcpy(ticket.username, "Hello AES");    printf("Username - %s/n", ticket.username);    printf("Ticket Id - %d/n", ticket.ticketId);    printf("Date - %s/n", ticket.date);    /* init vector */    unsigned char iv_enc[AES_BLOCK_SIZE], iv_dec[AES_BLOCK_SIZE];    RAND_bytes(iv_enc, AES_BLOCK_SIZE);    memcpy(iv_dec, iv_enc, AES_BLOCK_SIZE);    // buffers for encryption and decryption    const size_t encslength = ((inputslength + AES_BLOCK_SIZE) / AES_BLOCK_SIZE) * AES_BLOCK_SIZE;    unsigned char enc_out[encslength];    unsigned char dec_out[inputslength];    memset(enc_out, 0, sizeof(enc_out));    memset(dec_out, 0, sizeof(dec_out));    // so i can do with this aes-cbc-128 aes-cbc-192 aes-cbc-256    AES_KEY enc_key, dec_key;    AES_set_encrypt_key(aes_key, keylength, &enc_key);    AES_cbc_encrypt((unsigned char *)&ticket, enc_out, encslength, &enc_key, iv_enc, AES_ENCRYPT);    AES_set_decrypt_key(aes_key, keylength, &dec_key);    AES_cbc_encrypt(enc_out, dec_out, encslength, &dec_key, iv_dec, AES_DECRYPT);    printf("original:/t");    hex_print((unsigned char *)&ticket, inputslength);    printf("encrypt:/t");    hex_print(enc_out, sizeof(enc_out));    printf("decrypt:/t");    hex_print(dec_out, sizeof(dec_out));    USR_TICKET * dyc = (USR_TICKET *)dec_out;    printf("Username - %s/n", dyc->username);    printf("Ticket Id - %d/n", dyc->ticketId);    printf("Date - %s/n", dyc->date);    return 0;}

static int akcdecrypt(unsigned char *derived_key, unsigned char *data){	unsigned char out[CTLEN];	int pad, n, i, key_size;	AES_KEY akey;	unsigned char iv[16];	memcpy(iv, data + CTLEN - 32, 16);	if(AES_set_decrypt_key(derived_key, 128, &akey) < 0) {		fprintf(stderr, "AES_set_decrypt_key failed in crypt!/n");	}	AES_cbc_encrypt(data + CTLEN - 16, out + CTLEN - 16, 16, &akey, iv, AES_DECRYPT);	// now check padding	pad = out[CTLEN - 1];	if(pad < 1 || pad > 16) /* AES block size is 128 bits = 16 bytes */		// "Bad padding byte. You probably have a wrong password"		return -1;	n = CTLEN - pad;	key_size = n / 8;	if(key_size != 128 && key_size != 192 && key_size != 256)		// "invalid key size"		return -1;	for(i = n; i < CTLEN; i++)		if(out[i] != pad)			// "Bad padding. You probably have a wrong password"			return -1;	return 0;}

			void decrypt(AES_KEY &ctx, decrypt_output_type &dst, const decrypt_input_type &src, iv_type &iv)			{				// 16 
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