C语言使用openSSL库DES模块实现加密功能详解

wget ftp://ftp.openssl.org/source/openssl-1.0.0c.tar.gz
tar -zxf openssl-1.0.0c.tar.gz
cd openssl-1.0.0c/
./config --prefix=/usr/local --openssldir=/usr/local/ssl
make && make install
./config shared --prefix=/usr/local --openssldir=/usr/local/ssl
make clean
make && make install

#include <openssl/des.h>
#include <openssl/pkcs7.h>
#ifndef uchar
#define uchar unsigned char
#endif

libeay32.lib    // for windows
-lcrypto      // for linux

int encrypt_data(const char *_key, const char *_vt,char *_raw_ptr,size_t _raw_size
  , char **_dst_buf, size_t *_dst_size) {
  DES_key_schedule schedule;
  uchar key1[8];
  des_cblock *iv3;
  int pading ;
  size_t i, vt_size ;
  char *mid_buf;
  memset( key1,0,8);
  memcpy( key1, _key, 8 );
  DES_set_key_unchecked( (const_DES_cblock*)&key1, &schedule);
  vt_size = strlen( _vt );
  iv3 = (des_cblock *)malloc(vt_size * sizeof(uchar));
  memcpy(iv3,_vt,vt_size);
  pading = 8 - (_raw_size % 8);
  *_dst_size = _raw_size + pading;
  mid_buf = (char*)malloc(*_dst_size);
  memcpy(mid_buf,_raw_ptr,_raw_size );
  for (i = _raw_size ; i < *_dst_size; i++ ) {
    mid_buf[i] = pading;
  }
  *_dst_buf = (char*)malloc(*_dst_size);
  DES_cbc_encrypt( (const uchar*)mid_buf, (unsigned char *)*_dst_buf, *_dst_size, &schedule, iv3, DES_ENCRYPT);
  free(iv3);
  free(mid_buf);
  return 1;
}

int decrypt_data(const char *_key, const char *_vt,char *_raw_ptr,size_t _raw_size
    , char **_dst_buf, size_t *_dst_size ) {
  DES_key_schedule schedule;
  uchar key1[8];
  des_cblock *iv3;
  int pading ;
  size_t i, vt_size ;
  char *mid_buf;
  memset( key1,0,8);
  memcpy( key1, _key, 8 );
  DES_set_key_unchecked( (const_DES_cblock*)&key1, &schedule);
  vt_size = strlen( _vt );
  iv3 = (des_cblock *)malloc(vt_size * sizeof(uchar));
  memcpy(iv3,_vt,vt_size);
  *_dst_buf = (char*)malloc(_raw_size);
  DES_cbc_encrypt( (const uchar*)_raw_ptr, *_dst_buf, _raw_size, &schedule, iv3, DES_DECRYPT);
  free(iv3);
  return 1;
}

import glob
env = Environment()
env["CPPPATH"] = [ '/home/abel/lib/openssl-1.0.2f/include' ]
env['LIBPATH'] = [ '/home/abel/lib/openssl-1.0.2f' ]
env['CPPDEFINES'] = ['LINUX', '_DEBUG' ]
env['CCFLAGS'] = '-g -std=gnu99'
env['LIBS'] = [ 'm', 'crypto', 'dl', 'profiler' ]
env.Program( target = "./test_des", source = ( glob.glob( './*.c' ) ) )

int test_fun( int agrn, char *agrv[] ) {
  char *_key = "jkl;!@#$";
  char *_vt = "asdf!@#$";
  char *_raw_ptr ;
  size_t _raw_size;
  char *_dst_buf;
  size_t _dst_size;
  char *_final_buf;
  size_t _final_size;
  _raw_ptr = (char *)malloc(sizeof(char)*5);
  memcpy(_raw_ptr, "hello", 5);
  _raw_size = 5;
  encrypt_data(_key, _vt,_raw_ptr,_raw_size
      , &_dst_buf, &_dst_size) ;
  decrypt_data(_key,_vt, _dst_buf, _dst_size, &_final_buf, &_final_size );
  printf( "final: %s\n", _final_buf );
  free(_dst_buf);
  return 0;
}