大学密码学实验报告(含代码)试验2对称密码算法

1、西华大学计算机系上机实践报告课程名称：密码学指导教师：纪四维上机实践名称：对称密码算法上机实践编号：a01年级：07级上机实践成绩：姓名：范存勇学 号 ：上机实践日期：2009-11-10312007080605104组号：上机实践时间14： 00-17： 20一、目的通过用des算法对实际数据进行加密和解密来深刻了解des的运行原理。二、内容与设计思想a) 算法分析。对加密解密时主要用到的五个函数进行分析。i. 密钥生成函数ii. 加密函数iii. 解密函数iv. 测试函数v. 密钥长度检验函数b) 使用实例分析。i. 对一个文件进行加密解密，提交程序代码和执行结果。ii. 加密时，将输入(

2、如64比特分组)改变一位，比较输出的变化，并说 明原因。三、使用环境运行windows 或linux 操作系统的 pc机，具有gcc(linux)、vc(windows)等c语言编译环境四、核心代码及调试过程#ifndef crypt_h_ #define crypt_h_ #include <assert.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <time.h>#include <ctype.h>#include <

3、;limits.h>#ifdef _cplusplus extern "c" #endif/* version */#define crypt 0x0096#define scrypt ”0.96”/* error codes will be expanded in future releases */ enum crypt_ok=0,/* result ok */crypt_invalid_keysize, /* invalid key size given */ crypt_invalid_rounds, /* invalid number of rounds *

4、/ crypt_fail_testvector,产 algorithm failed test vectors */；#define des/* use small code where possible */#define small_code/* enable self-test test vector checking */#define ltc.test/* type of argument checking, 0=default, 1 =fatal and 2=none */#define argtype 0/* chl-01-1 */* controls endianess and

5、 size of registers leave uncommented to get platform neutral slower code */* detect x86-32 machines somewhat */#ifdefined(intel_cc) | (defined(_msc_ver) && defined(win32) | (defined(_gnuc_) && (defined(_djgpp_) | defined(_cygwin_) | defined(_mingw32_) | defined(_i386)#define endian_l

6、ittle#define endian_32bitword#endif/* detects mips r5900 processors (ps2) */#if (defined(_r5900) | defined(r5900) | defined(_r5900_) && (defined(_mips) | defined(_mips_) | defined(mips)#define endian_little#define endian_64bitword#endif怦 #define endian_little 犁严 #define endian_big */* #defin

7、e endian_32bitword */* #define endian_64bitword */#if (defined(endian_big) | defined(endian_little)&& !(defined(endian_32bitword) | defined(endian_64bitword) #error you must specify a word size as well as endianess#endif#讦!(defined(endian_big) | defined(endian_little) #define endian.neutral#

8、endif/* fix for msvc .evil! */#ifdef_msc_ver#define const64(n) n # ui64 typedef unsigned _int64 ulong64;#else#define const64(n) n # ull typedef unsigned long long ulong64;#endif/* this is the "32-bit at least" data type* re-define it to suit your platform but it must be at least 32-bits */

9、typedef unsigned long ulong32;/* - helper macros*/#ifdef endian.neutral#define store32l(x, y) (y)3 = (unsigned char)(x)»24)&255); (y)2j = (unsigned char)(x)»16)&255);(y)l = (unsigned char)(x)»8)&255); (y)0 = (unsigned char)(x)&255); #define load32l(x, y) x = (unsigned

10、long)(y)3 & 255)«24) | (unsigned long)(y)2 & 255)«16) | (unsigned long)(y)l & 255)«8)| (unsigned long)(y)|0| & 255); #define store32h(x, y) (y)|0| = (unsigned char)(x)»24)&255); (y)| 1 = (unsigned char)(x)»16)&255);(y)2 = (unsigned char)(x)»8)&am

11、p;255); (y)3 = (unsigned char)(x)&255); #define load32h(x, y) x = (unsigned long)(y)|0 & 255)«24) | (unsigned long)(y)l & 255)«16) | (unsigned long)(y)2 & 255)«8)| (unsigned long)(y)3 & 255); #enchf/* endian_neutral */#ifdef endian_little#define store32h(x, y) (y)0

12、 = (unsigned char)(x)»24)&255); (y)l = (unsigned char)(x)»16)&255);(y)2 = (unsigned char)(x)»8)&255); (y)3 = (unsigned char)(x)&255); #define load32h(x, y) x = (unsigned long)(y)0 & 255)«24) | (unsigned long)(y)l & 255)«16) | (unsigned long)(y)2 &

13、 255)«8)| (unsigned long)(y)3 & 255); #ifdef endian_32bitword#define store32l(x, y) unsigned long _t = (x); memcpy(y, &_t, 4); #define load32l(x, y) memcpy(&(x), y, 4);#else /* 64-bit words then */#define store32l(x, y) unsigned long _t = (x); memcpy(y, &_t, 4); #define load32l(

14、x, y) memcpy(&(x), y, 4); x &二 oxffffffff; #endif/* endian_64bitword */#endif/* endian_little */#ifdefendian_big#define store32l(x, y) (y)oj = (unsigned char)(x)»24)&255); (y)l = (unsigned char)(x)»16)&255);(y)2 = (unsigned char)(x)»8)&255); (y)3 = (unsigned char)(

15、x)&255); #define load32l(x, y) x = (unsigned long)(y)0 & 255)«24) | (unsigned long)(y)l & 255)«16) | (unsigned long)(y)2 & 255)«8)| (unsigned long)(y)3 & 255); #ifdef endian_32bitword#define store32h(x, y) unsigned long _t = (x); memcpy(y, &_t, 4); #define load

16、32h(x, y)memcpy(&(x), y, 4);#else /* 64-bit words then */#define store32h(x, y) unsigned long _t = (x); memcpy(y, &_t, 4); #define load32h(x, y) memcpy(&(x), y, 4); x &二 oxffffffff; #endif/* endian.64bitword */#endif/* endian_big */#define bswap(x) (x»24)&0x000000fful) | (x&

17、#171;24)&0xff000000ul)| (x»8)&0x0000ff00ul)| (x«8)&0x00ff0000ul)#ifdef_msc_ver#pragma intrinsic(rotl)#define ror(x,n) _lrotr(x,n)#define rol(x,n) _lrotl(x,n)#elif defined(_gnuc_) && defined(_i386_) && !defined(intel_cc)static inline unsigned long rol(unsigned lo

18、ng word, int i)_asm_(hroll %cl,%on:n=rn (word):”0” (word),ncn (i);return word;static inline unsigned long ror(unsigned long word, int i)_asm_(nrorl %cl,%0”:'-rh (word):”0” (word),nch (i);return word;#else/* rotates the hard way */#define rol(x, y) (unsigned long)(x)«(unsigned long)(y)&3

19、1) | (unsigned long)(x)&oxfffffffful)»(unsigned long)(32-(y)&31) & oxfffffffful)#define ror(x, y) (unsigned long)(x)&oxfffffffful)»(unsigned long)(y)&31) | (unsigned long)(x)«(unsigned long)(32-(y)&31) & oxfffffffful)#endif/* extract a byte portably */#ifde

20、f_msc_ver#define byte(x, n) (unsigned char)(x) » (8 * (n)#else#define byte(x, n) (x) » (8 * (n) & 255)#endiftypedef struct des_key ulong32 ek32, dk32;symmetric_key;extern int des_setup(const unsigned char *key, int keylen, int num_rounds? symmetric_key *skey);extern void des_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key * key); extern void des_ecb_decrypt(const unsigned char un