利用OpenSSL中EVP封装调用对称加密算法的通用代码

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Code:

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <openssl/evp.h>#ifdef _MSC_VER#pragma comment(lib,"libeay32.lib")typedef unsigned char uint8_t;#define bzero(a, b) memset( a, 0x0, b )#else#include <stdint.h>#endif// {EA6E74BD-1A25-4b06-8493-B0F9319BD3B9}static const uint8_t ks_des_ede3[] = {0xea, 0x6e, 0x74, 0xbd, 0x1a, 0x25, 0x4b, 0x06, 0x84, 0x93, 0xb0, 0xf9, 0x31, 0x9b, 0xd3, 0xb9,0x9b, 0xc3, 0x25, 0xa4, 0x7f, 0x43, 0xa0, 0x44};// {73243D40-FFFD-47fe-87A3-3A1E0DABCAC7}static const uint8_t ks_aes_128[] = { 0x73, 0x24, 0x3d, 0x40, 0xff, 0xfd, 0x47, 0xfe, 0x87, 0xa3, 0x3a, 0x1e, 0x0d, 0xab, 0xca, 0xc7 };// {2D89EA6D-1F3C-4b47-AA27-5F6B78800874}static const uint8_t ks_aes_192[] = { 0x2d, 0x89, 0xea, 0x6d, 0x1f, 0x3c, 0x4b, 0x47,0xaa, 0x27, 0x5f, 0x6b, 0x78, 0x80, 0x08, 0x74,0x8b, 0x57, 0x7b, 0x84, 0x45, 0x8f, 0xe1, 0x7d};// {C20A94E8-601F-409d-B957-33A0E539C20A}static const uint8_t ks_aes_256[] = { 0xc2, 0x0a, 0x94, 0xe8, 0x60, 0x1f, 0x40, 0x9d, 0xb9, 0x57, 0x33, 0xa0, 0xe5, 0x39, 0xc2, 0x0a,0x0f, 0xe3, 0x39, 0xdd, 0x5c, 0x02, 0x4f, 0x11, 0x96, 0x67, 0xd5, 0x4d, 0x4d, 0xe8, 0xb1, 0x3c };// 典型的加密算法密钥长度(byte)#define DES_KEY_LENGTH8#define DES_EDE_KEY_LENGTH 16#define DES_EDE3_KEY_LENGTH 24#define AES_128_KEY_LENGTH 16#define AES_192_KEY_LENGTH24#define AES_256_KEY_LENGTH32/*=============================================================================*/// Function name : cipher_dump// Description : dump cipher infomation// Input : // const EVP_CIPHER * ctx// Return type : void none /*=============================================================================*/void cipher_dump(const EVP_CIPHER * ctx){//EVP_CIPHER_CTX_cipher() int key_len = EVP_CIPHER_key_length( ctx );int block_size = EVP_CIPHER_block_size( ctx );int iv_len = EVP_CIPHER_iv_length( ctx );int type = EVP_CIPHER_type(ctx );int mode = EVP_CIPHER_mode( ctx );int nid = EVP_CIPHER_nid( ctx );printf( "=====================================/n" );printf( "key length=%d /n", key_len );printf( "block size=%d /n", block_size );printf( "iv length=%d /n", iv_len );printf( "type=%d /n", type );printf( "mode=%d /n", mode );printf( "nid=%d /n", nid );}/*=============================================================================*/// Function name : calc_cipher_length// Description : calc cipher text length// Input : // EVP_CIPHER_CTX * ctx// int inlen// Return type : int return cipher text length /*=============================================================================*/int calc_cipher_length(EVP_CIPHER_CTX * ctx,int inlen){int block_size = EVP_CIPHER_CTX_block_size( ctx );int block_cnt = 0;int block_final = 0;int cipher_length = 0;if ( inlen < block_size ) {printf( "calc cipher length = %d/n", block_size );return block_size;}block_cnt = inlen / block_size;cipher_length = block_cnt * block_size;block_final = inlen - cipher_length;if ( block_final >= 0 ) {block_final = block_size;}cipher_length += block_final;printf( "calc cipher length = %d/n", cipher_length );return cipher_length;}/*=============================================================================*/// Function name : do_crypt// Description : 使用3DES 加解密数据// Input : // uint8_t *in输入数据缓冲// int inlen输入数据长度// uint8_t **out输出数据缓冲指针// int *outlen输出数据长度// int do_encrypt加解密标志(1:加密; 0:解密)// Return type : int success return 0 or return -1 /*=============================================================================*/int do_crypt(uint8_t *in, int inlen, uint8_t **out, int *outlen, int do_encrypt ){uint8_t *key = (uint8_t *)ks_des_ede3; int len; EVP_CIPHER_CTX ctx; //uint8_t outbuf[1024 + EVP_MAX_BLOCK_LENGTH];uint8_t *outbuf = NULL; uint8_t *pb = NULL;int retval = 0;int cipher_length = 0;if ( inlen <= 0 || in == NULL ) {return 0;} EVP_CIPHER_CTX_init(&ctx); // 使用Triple DES retval = EVP_CipherInit(&ctx, EVP_des_ede3_cbc(), key, NULL, do_encrypt );// 计算输出缓冲长度if ( do_encrypt ) {cipher_length = calc_cipher_length( &ctx, inlen );outbuf = (uint8_t *)malloc( cipher_length );}else {outbuf = (uint8_t *)malloc( inlen );}pb = outbuf; // evp 调用加解密操作 if (!EVP_CipherUpdate(&ctx, pb, &len, in, inlen)) { /* Error */ free( outbuf ); EVP_CIPHER_CTX_cleanup(&ctx); return 0; } *outlen = len; pb += len;len = 0; if (!EVP_CipherFinal(&ctx, pb,&len)) { /* Error */ free( outbuf ); EVP_CIPHER_CTX_cleanup(&ctx); return 0; } *outlen += len;pb = outbuf;// 如为解密则重新分配解密后数据大小缓冲if ( !do_encrypt ) {if ( inlen != ( *outlen ) ) {pb = (uint8_t *)malloc( *outlen );memcpy( pb, outbuf, *outlen );free( outbuf );}} *out= pb; EVP_CIPHER_CTX_cleanup(&ctx); return 1;}int main(int argc, char* argv[]){/*OPENSSL_add_all_algorithms_noconf();OpenSSL_add_all_ciphers();OpenSSL_add_all_digests();*/// 变换plain_text 大小分别为 5, 8, 13, 16uint8_t plain_text[13] = { "test" };uint8_t *cipher_text = NULL;uint8_t *out_text = NULL;int inlen = 0, outlen = 0;int len = 0;cipher_dump( EVP_des_ede3_cbc() );cipher_dump( EVP_aes_128_cfb128() );printf( "=============/n");do_crypt( plain_text, sizeof( plain_text), &cipher_text, &outlen, 1 );printf( "crypt out length = %d/n", outlen );do_crypt( cipher_text, outlen, &out_text, &len, 0 );printf( "crypt out length = %d/n", len );free( cipher_text );free( out_text );return 0;}

加密长度5bytes

# gcc t3.c -o t3 -lssl# ./t3=====================================key length=24block size=8iv length=8type=44mode=2nid=44=====================================key length=16block size=1iv length=16type=421mode=3nid=421=============calc cipher length = 8crypt out length = 8crypt out length = 5

加密长度8bytes

加密长度13bytes

加密长度16bytes