使用openssl库实现des,3des加密

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <openssl/des.h> 
/************************************************************************ 
** 本例采用： 
** 3des-ecb加密方式； 
** 24位密钥，不足24位的右补0x00； 
** 加密内容8位补齐，补齐方式为：少1位补一个0x01,少2位补两个0x02,... 
** 本身已8位对齐的，后面补八个0x08。 
************************************************************************/ 
int main(void) 
{ 
    int docontinue = 1; 
    char *data = "hello world!"; /* 明文 */ 
    int data_len; 
    int data_rest; 
    unsigned char ch; 
    unsigned char *src = NULL; /* 补齐后的明文 */ 
    unsigned char *dst = NULL; /* 解密后的明文 */ 
    int len; 
    unsigned char tmp[8]; 
    unsigned char in[8]; 
    unsigned char out[8]; 
    char *k = "01234567899876543210"; /* 原始密钥 */ 
    int key_len; 
    #define LEN_OF_KEY 24 
    unsigned char key[LEN_OF_KEY]; /* 补齐后的密钥 */ 
    unsigned char block_key[9]; 
    DES_key_schedule ks,ks2,ks3; 
    /* 构造补齐后的密钥 */ 
    key_len = strlen(k); 
    memcpy(key, k, key_len); 
    memset(key + key_len, 0x00, LEN_OF_KEY - key_len); 
    /* 分析补齐明文所需空间及补齐填充数据 */ 
    data_len = strlen(data); 
    data_rest = data_len % 8; 
    len = data_len + (8 - data_rest); 
    ch = 8 - data_rest; 
    src = (unsigned char *)malloc(len); 
    dst = (unsigned char *)malloc(len); 
    if (NULL == src || NULL == dst) 
    { 
        docontinue = 0; 
    } 
    if (docontinue) 
    { 
        int count; 
        int i; 
        /* 构造补齐后的加密内容 */ 
        memset(src, 0, len); 
        memcpy(src, data, data_len); 
        memset(src + data_len, ch, 8 - data_rest); 
        /* 密钥置换 */ 
        memset(block_key, 0, sizeof(block_key)); 
        memcpy(block_key, key + 0, 8); 
        DES_set_key_unchecked((const_DES_cblock*)block_key, &ks); 
        memcpy(block_key, key + 8, 8); 
        DES_set_key_unchecked((const_DES_cblock*)block_key, &ks2); 
        memcpy(block_key, key + 16, 8); 
        DES_set_key_unchecked((const_DES_cblock*)block_key, &ks3); 
        printf("before encrypt:
"); 
        for (i = 0; i < len; i++) 
        { 
            printf("0x%.2X ", *(src + i)); 
        } 
        printf("
"); 
        /* 循环加密/解密，每8字节一次 */ 
        count = len / 8; 
        for (i = 0; i < count; i++) 
        { 
            memset(tmp, 0, 8); 
            memset(in, 0, 8); 
            memset(out, 0, 8); 
            memcpy(tmp, src + 8 * i, 8); 
            /* 加密 */ 
            DES_ecb3_encrypt((const_DES_cblock*)tmp, (DES_cblock*)in, &ks, &ks2, &ks3, DES_ENCRYPT); 
            /* 解密 */ 
            DES_ecb3_encrypt((const_DES_cblock*)in, (DES_cblock*)out, &ks, &ks2, &ks3, DES_DECRYPT);
            /* 将解密的内容拷贝到解密后的明文 */ 
            memcpy(dst + 8 * i, out, 8); 
        } 
        printf("after decrypt :
"); 
        for (i = 0; i < len; i++) 
        { 
            printf("0x%.2X ", *(dst + i)); 
        } 
        printf("
"); 
    } 
    if (NULL != src) 
    { 
        free(src);
        src = NULL; 
    } 
    if (NULL != dst) 
    { 
        free(dst); 
        dst = NULL; 
    } 
    return 0; 
}