大学密码学实验报告（含代码） 试验4 HASA算法MD.doc

西华大学计算机系上机实践报告课程名称：密码学年级：07级 上机实践成绩：指导教师：纪四维姓名： 范存勇上机实践名称：HASA算法MD5学号： 312007080605104上机实践日期：2009-11-10上机实践编号：A01组号： 上机实践时间14：00-17：20一、 目的通过实际编程了解MD5算法， 加深对MD5的性质、原理的理解。二、 内容与设计思想a) 算法分析。b) 使用实例分析i. 在密码算法库中，找出关于MD5算法的部分对一个文件进行处理，计算它的HASH值，提交程序代码和运算结果。ii. 微软的系统软件都有MD5验证，尝试查找软件的MD5值。同时，在Windows操作系统中，通过开始- 运行sigverif命令，利用数字签名查找验证非Windows的系统软件。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 #include mycrypt.hint hash_file(int hash, const char *fname, unsigned char *dst, unsigned long *outlen)#ifdef NO_FILE return CRYPT_NOP;#else FILE *in; int err; _ARGCHK(fname != NULL); _ARGCHK(dst != NULL); _ARGCHK(outlen != NULL); if (err = hash_is_valid(hash) != CRYPT_OK) return err; in = fopen(fname, rb); if (in = NULL) return CRYPT_FILE_NOTFOUND; err = hash_filehandle(hash, in, dst, outlen); if (fclose(in) != 0) return CRYPT_ERROR; return err;#endif/* LibTomCrypt, modular cryptographic library - Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenisiahu.ca, */#include mycrypt.hint hash_filehandle(int hash, FILE *in, unsigned char *dst, unsigned long *outlen)#ifdef NO_FILE return CRYPT_NOP;#else hash_state md; unsigned char buf512; size_t x; int err; _ARGCHK(dst != NULL); _ARGCHK(outlen != NULL); _ARGCHK(in != NULL); if (err = hash_is_valid(hash) != CRYPT_OK) return err; if (*outlen hash_descriptorhash.hashsize) return CRYPT_BUFFER_OVERFLOW; *outlen = hash_descriptorhash.hashsize; hash_descriptorhash.init(&md); do x = fread(buf, 1, sizeof(buf), in); hash_cess(&md, buf, x); while (x = sizeof(buf); hash_descriptorhash.done(&md, dst);#ifdef CLEAN_STACK zeromem(buf, sizeof(buf);#endif return CRYPT_OK;#endif/* LibTomCrypt, modular cryptographic library - Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenisiahu.ca, */#include mycrypt.hint hash_memory(int hash, const unsigned char *data, unsigned long len, unsigned char *dst, unsigned long *outlen) hash_state md; int err; _ARGCHK(data != NULL); _ARGCHK(dst != NULL); _ARGCHK(outlen != NULL); if (err = hash_is_valid(hash) != CRYPT_OK) return err; if (*outlen hash_descriptorhash.hashsize) return CRYPT_BUFFER_OVERFLOW; *outlen = hash_descriptorhash.hashsize; hash_descriptorhash.init(&md); hash_cess(&md, data, len); hash_descriptorhash.done(&md, dst); return CRYPT_OK;五、总结通