DES加密算法的C语言实现

1、Generated by Foxit PDF Creator © Foxit Softwarehttp:/www.foxitsoftware.coni For evaluation only.#include <stdio.h> #include<memory.h> #include<string.h> #include <time.h> #define Decode 0 #define Encode 1 bool Sub_Key1648;明文初始置换unsigned char Initial =58, 50,42, 34, 26,18

2、,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, 159, 51,43, 35, 27,19,11, 3,61,53, 45, 37, 29,21,13, 5,63, 55, 47, 39,31,23, 15, 7 ；最终置换unsigned char Final=40, 8, 48, 16, 56, 24, 64, 32,39, 7, 47, 15, 55, 23, 63, 31,38, 6, 46, 14,

3、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 ；S-盒置换unsigned char S_Box864=/* S1 */Generated by Foxit PDF Creator © Foxit Softwarehttp:/www.foxitsoftware.coni For evaluation only.14, 4, 13,

4、0, 7, 0, 15,5, 3, 8,4,1, 2,15,11, &7, 4,14, 2,13,1,14, 8,13, 6,3.10, 6,12, 5, 9,1.10, 6,12,11, 9,2,11,15,12, 9, 7,3,10,5, 0, 15, 12, 8, 2, 4,9, 1, 7, 5, 11, 3,Generated by Foxit PDF Creator © Foxit Softwarehttp:/www.foxitsoftware.coni For evaluation only.14,10, 0, 6, 13,/* S2 */15,1, 8,14,

5、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, 911, 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

6、,12,5,10,14, 7,1,10,13,o,6,9,8,7, 4,15,14, 311, 5, 2, 12,/* S4 */7,13,14, 3, 0, 6,9,10,1,2,8, 5, 11, 12, 415,13, 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 */,12, 4, 1,7,10,11, 6, 8, 5, 3,15,13, 0, 14

7、,9,14,11, 2,12, 4, 7,13,1,8, 6,4, 2,3, 0,14,11,10, 4, 5,1,11,10,13, 7,8,12, 7, 1,14, 3,5, 0,15,10, 3,8,15,2,13,9,12, 5,6,15, 0,9,6,9,/* 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,&12, 3,7, 0, 4,10,1,13,11, 6,4, 3, 2,12,9, 5

8、, 15,10, 11, 14,1,7, 6,0, 8,13,/* S7 */2X31-X1-5ToXdiXIdi4di5di5XI4diodiT2T3diTXIT4h&21/* 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；unsigne

9、d char Key_Exchange56= _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；压缩变换unsigned char Compression=14,17,11,24, 1, 5, 3, 28,15, 6,21, 10,23, 19, 12, 4

10、, 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；扩展变换unsigned char Expansion=324&1, 2, 3, 4, 5,5, 6, 7, 8, 9,9, 10, 11, 12, 13,13, 14, 15, 16, 17, 17, 18, 19, 20,21, 21,22, 23, 24, 25,25, 26, 27, 28, 29, 29, 30, 31,32, 1P_

11、盒置换unsigned char P_Box= _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 ；密钥置换unsigned char KeyQ=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, 4

12、6, 38, 30, 22,14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 ；/unsigned char Key_Move= _1,1 ,2,2,2,2,2,2,1,2,2,2,2,2,2,1;void Key_Process(char *);void DES(char*,char*,int);void Generate_SubKey(bool*,bool*);void Rotate_Key(bool *,int);void lnitial_Exchange(char *, booF,booF );void Exchange_Key(c

13、ha*, bool*);void Expand_Right(boo匚 bool*);void Sunction(bool* ,bool*);void P_function(bool * );void Final_Exchange(booF , bool*,char*);void BitToByte(char *Out, const bool *ln, int bits);主函数int main(int argc,char*argv)unsigned long start,end;/time when execution beginsstart = clock();char Final_Resu

14、lt12=0;char Message12=0;char S_Key8=123,4,5,6,7,8;64bits打开文件用于输入FILE *input = fopen( argv1, V);if(ferror( input)retur n 0 ;创建文件用于输出密文FILE *encyption = fopen(argv2,Hw");if(ferror( encyption )return 0 ;创建文件用于输出解密后的明文FILE *decyption = fopen(argvw“)；if(ferror( decyption )return 0;while( Ifeof(input

15、)int i=0;while( Ifeof(input) && i<8 )Messagei=fgetc(input);i+；if (i=0)break;else if(i<8)for(;i<8;i+) Messagei-O*;Key_Process(S_Key);DES(Message,Final_Result,Encode);Final_Result8=0;fputs( Final_Result, encyption );memset(Message,0,8);DES(Final_Result,Message,Decode);Message 二 0;fput

16、s( Message, decyption );/time when execution endsend = clock();pintf(HThe execution time is %ld msrT, end-start); return 0;void Key_Process(char *S_Key) " "int round ;bool Bit_Key56;/56bitsExchange_Key(S_Key,Bit_Key);for(round = 0 丁ound<16;round+)/KL->消息左28位，KR->消息右28位bool*KL = &a

17、mp;Bit_KeyO, *KR = &Bit_Key28;循环左移Rotate_Key(KL,Key_Moveround); Rotate_Key(KR,Ky_Moveround);产生子密潮_Generate_SubKey(Bit_Key,Sub_Keyround); "void Exchange_Key(char *Key , bool* New_Key) int i j;bool Bit_Key64;/Transform the initial key to bool type for(i = 0 ;i<8;i+)forO=0;j<8;j+)Bit_Key

18、i*8+j = (Keyi»j)&OxO1;for(i=0;i<56;i+) New_Keyi=Bit_KeyKey_Exchangei-1; "void Rotate_Key(bool*Key ,int round) _bool temp64;/void *memcpy( void *to, const void *from, size_t count); 函数从from中复制count个字符到to中，并返回to 指针memcpy(temp, Key, round); memcpy(Key, Key+round, 28-round); memcpy(Key+

19、28-round, temp, round);void Generate_SubKey(bool*lnput, bool* Output) _for(int i二0;i<48;i+ )Outputi=lnputCompressioni-1;/DES函数void DES( cha广Message,char *Final_Result,int type) _bool Right32;/32bitsbool Left32;/32bitsbool Expanded_Right48;扩展后的右消息bool flag32;/ffl于左右消息交换bool Result148;/48bitsbool R

20、esult232;/32bitsint round ,i;In itial_Excha nge(Message 丄 eft,Right);加密算法if(type = Encode)for( round = 0 ; round < 16 ;ound+ )memcpy(flag,Right,32);Expand_Right(Right,Expanded_Right);for( i = 0 ; i<48 ; i+ )Result1i=Expanded_RightiASub_Keyroundi;S_fun ction(Result1 ,Result2);P_function(Result2

21、);for( i = 0 ; i<32 ; i+)Righti = Result2iALefti; memcpy(Left,flag,32);解密算法else if(type = Decode)for( round = 15 ; round >=0 ; round ) memcpy(flag,Left,32);Expa nd_Right(Left,Expa nded_Right);for( i = 0; i<48 ; i+ )Resultl i=Expanded_RightiASub_Keyroundi;S_f unction(Result1 ,Result2);P_func

22、tion(Result2);for( i = 0 ; i<32 ; i+)Lefti = Result2iARighti;memcpy(Right,flag,32);Final_Exchange( Left, Right, Final_Result);void lnitial_Exchange(chaMessage , boorLeft,bool*Right)bool temp64;int i,j；把Message转化成bit形式for(i=0;i<8;i+) for0=O;j<8;j+) tempi*8+j= (Messagei»j)&0x01;for(i=0;i<32;i+)Lefti=templnitiali-1;for(;i<64;i+)Righti-32=templnitiali-1;void Expand_Right(bool*lnput, bool*Output