DES.zip_DES原理_DES源代码注释

#include <iostream.h> #include <stdio.h> #include "memory.h" #include "WjcDes.h" // initial permutation IP const static char IP_Table[64] = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 }; // final permutation IP^-1 const static char IPR_Table[64] = { 40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25 }; // expansion operation matrix static const char E_Table[48] = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 }; // 32-bit permutation function P used on the output of the S-boxes const static char P_Table[32] = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25 }; // permuted choice table (key) const static char PC1_Table[56] = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }; // permuted choice key (table) const static char PC2_Table[48] = { 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32 }; // number left rotations of pc1 const static char LOOP_Table[16] = { 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1 }; // The (in)famous S-boxes const static char S_Box[8][4][16] = { // S1 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13, // S2 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9, // S3 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12, // S4 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14, // S5 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3, // S6 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13, // S7 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12, // S8 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 }; ////////////////////////////////////////////////////////////////////////// typedef bool (*PSubKey)[16][48];///?????指针数组？ ////////////////////////////////////////////////////////////////////////// static void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type);//标准DES加/解密 static void SetKey(const char* Key, int len);// 设置密钥 static void SetSubKey(PSubKey pSubKey, const char Key[8]);// 设置子密钥 static void F_func(bool In[32], const bool Ki[48]);// f 函数 static void S_func(bool Out[32], const bool In[48]);// S 盒代替 static void Transform(bool *Out, bool *In, const char *Table, int len);// 变换 static void Xor(bool *InA, const bool *InB, int len);// 异或 static void RotateL(bool *In, int len, int loop);// 循环左移 static void ByteToBit(bool *Out, const char *In, int bits);// 字节组转换成位组 static void BitToByte(char *Out, const bool *In, int bits);// 位组转换成字节组 ////////////////////////////////////////////////////////////////////////// static bool SubKey[2][16][48];// 16圈子密钥 static bool Is3DES;// 3次DES标志 static char Tmp[256], deskey[16]; ////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////// // Code starts from Line 130 ////////////////////////////////////////////////////////////////////////// bool Des_Go(char *Out, char *In, long datalen, const char *Key, int keylen, bool Type)//bool 类型的变量非0即1 { if( !( Out && In && Key && (datalen=(datalen+7)&0xfffffff8) ) ) //out输入的字符数组，in输入的字符数组，datalen数组长度，key密钥数组，keylen密钥长度 return false; SetKey(Key, keylen);// 设置密钥 if( !Is3DES ) // 1次DES { for(long i=0,j=datalen>>3; i<j; ++i,Out+=8,In+=8) DES(Out, In, &SubKey[0], Type); } else { // 3次DES 加密:加(key0)-解(key1)-加(key0) 解密::解(key0)-加(key1)-解(key0) for(long i=0,j=datalen>>3; i<j; ++i,Out+=8,In+=8) { DES(Out, In, &SubKey[0], Type); DES(Out, Out, &SubKey[1], !Type); DES(Out, Out, &SubKey[0], Type); } } return true; } void SetKey(const char* Key, int len)// 设置密钥 { memset(deskey, 0, 16);//初始化deskey /*memset()的函数， 它可以一字节一字节地把整个数组设置为一个指定的值。 memset()函数在mem.h头文件中声明，它把数组的起始地址作为其第一个参数， 第二个参数是设置数组每个字节的值，第三个参数是数组的长度(字节数，不是元素个数)。其函数原型为： 　　　　void *memset(void*，int，unsigned)； 　　其中void*表示地址 　　　　memset()的第一个实参是数组名，数组名作参数即数组作参数*/ memcpy(deskey, Key, len>16?16:len);//从key中拷贝16个字节的字符到deskey中.超过16字节后只取前16字节 SetSubKey(&SubKey[0], &deskey[0]);// 设置子密钥 Is3DES = len>8 ? (SetSubKey(&SubKey[1], &deskey[8]), true) : false; //当keylen>8时系统自动使用3次DES加/解密,否则使用标准DES加/解密 } void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type)//标准DES加/解密 { static bool M[64], tmp[32], *Li=&M[0], *Ri=&M[32]; int k; ByteToBit(M, In, 64);// 字节组转换成位组 ////////第一步：初始IP置换//////////////////////////////////////////////////////////////////////////////////////////////////////////// Transform(M, M, IP_Table, 64);//64位明文进行初始IP置换，产生64位输出 if( Type == ENCRYPT ) { for(int i=0; i<16; ++i)//加密 { memcpy(tmp, Ri, 32); F_func(Ri, (*pSubKey)[i]);// f 函数 Xor(Ri, Li, 32); memcpy(Li, tmp, 32); printf("%d:\t",(i+1)); for(k=0;k<64;k++) printf("%d",M[k]); printf("\n"); } } else { for(int i=15; i>=0; --i) //解密 { memcpy(tmp, Li, 32); F_func(Li, (*pSubKey)[i]);