利用OpenSSL中EVP封装调用对称加密算法的通用代码

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_LENGTH		8
#define DES_EDE_KEY_LENGTH  16
#define DES_EDE3_KEY_LENGTH 24

#define AES_128_KEY_LENGTH  16
#define AES_192_KEY_LENGTH	24
#define AES_256_KEY_LENGTH	32


/*=============================================================================*/
//  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, 16
	uint8_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=24
block size=8
iv length=8
type=44
mode=2
nid=44
=====================================
key length=16
block size=1
iv length=16
type=421
mode=3
nid=421
=============
calc cipher length = 8
crypt out length = 8
crypt out length = 5

加密长度8bytes

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

加密长度13bytes

# gcc t3.c -o t3 -lssl
# ./t3
=====================================
key length=24
block size=8
iv length=8
type=44
mode=2
nid=44
=====================================
key length=16
block size=1
iv length=16
type=421
mode=3
nid=421
=============
calc cipher length = 16
crypt out length = 16
crypt out length = 13

加密长度16bytes

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