desc语言源代码差分分析（差分分析法 des）

本篇文章给大家谈谈desc语言源代码差分分析，以及差分分析法 des对应的知识点，希望对各位有所帮助，不要忘了收藏本站喔。

本文目录一览：

• 1、求助：用C++编写 S盒的差分分析
• 2、DES加密算法C语言实现
• 3、用c语言写des加密算法
• 4、用C语言来实现DES加密算法（很急）两天内
• 5、密码学第一次实验报告：DES算法与差分攻击

求助：用C++编写 S盒的差分分析

你的语气让人很不爽，懒得看，估计也没人看；

祝你好运。

DES加密算法C语言实现

#includeiostream.h

class SubKey{ //定义子密钥为一个类

public:

int key[8][6];

}subkey[16]; //定义子密钥对象数组

class DES{

int encipher_decipher; //判断加密还是解密

int key_in[8][8]; //用户原始输入的64位二进制数

int key_out[8][7]; //除去每行的最后一位校验位

int c0_d0[8][7]; //存储经PC-1转换后的56位数据

int c0[4][7],d0[4][7]; //分别存储c0,d0

int text[8][8]; //64位明文

int text_ip[8][8]; //经IP转换过后的明文

int A[4][8],B[4][8]; //A,B分别存储经IP转换过后明文的两部分,便于交换

int temp[8][6]; //存储经扩展置换后的48位二进制值

int temp1[8][6]; //存储和子密钥异或后的结果

int s_result[8][4]; //存储经S变换后的32位值

int text_p[8][4]; //经P置换后的32位结果

int secret_ip[8][8]; //经逆IP转换后的密文

public:

void Key_Putting();

void PC_1();

int function(int,int); //异或

void SubKey_Production();

void IP_Convert();

void f();

void _IP_Convert();

void Out_secret();

};

void DES::Key_Putting() //得到密钥中对算法有用的56位

{

cout"请输入64位的密钥(8行8列且每行都得有奇数个1):\n";

for(int i=0;i8;i++)

for(int j=0;j8;j++){

cinkey_in[i][j];

if(j!=7) key_out[i][j]=key_in[i][j];

}

}

void DES::PC_1() //PC-1置换函数

{

int pc_1[8][7]={ //PC-1

{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}

};

int i,j;

for(i=0;i8;i++)

for(j=0;j7;j++)

c0_d0[i][j]=key_out[ (pc_1[i][j]-1)/8 ][ (pc_1[i][j]-1)%8 ];

}

int DES::function(int a,int b) //模拟二进制数的异或运算,a和b为整型的0和1,返回值为整型的0或1

{

if(a!=b)return 1;

else return 0;

}

void DES::SubKey_Production() //生成子密钥

{

int move[16][2]={ //循环左移的位数

1 , 1 , 2 , 1 ,

3 , 2 , 4 , 2 ,

5 , 2 , 6 , 2 ,

7 , 2 , 8 , 2 ,

9 , 1, 10 , 2,

11 , 2, 12 , 2,

13 , 2, 14 , 2,

15 , 2, 16 , 1

};

int pc_2[8][6]={ //PC-2

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

};

for(int i=0;i16;i++) //生成子密钥

{

int j,k;

int a[2],b[2];

int bb[28],cc[28];

for(j=0;j4;j++)

for(k=0;k7;k++)

c0[j][k]=c0_d0[j][k];

for(j=4;j8;j++)

for(k=0;k7;k++)

d0[j-4][k]=c0_d0[j][k];

for(j=0;j4;j++)

for(k=0;k7;k++){

bb[7*j+k]=c0[j][k];

cc[7*j+k]=d0[j][k];

}

for(j=0;jmove[i][1];j++){

a[j]=bb[j];

b[j]=cc[j];

}

for(j=0;j28-move[i][1];j++){

bb[j]=bb[j+1];

cc[j]=cc[j+1];

}

for(j=0;jmove[i][1];j++){

bb[27-j]=a[j];

cc[27-j]=b[j];

}

for(j=0;j28;j++){

c0[j/7][j%7]=bb[j];

d0[j/7][j%7]=cc[j];

}

for(j=0;j4;j++) //L123--L128是把c0,d0合并成c0_d0

for(k=0;k7;k++)

c0_d0[j][k]=c0[j][k];

for(j=4;j8;j++)

for(k=0;k7;k++)

c0_d0[j][k]=d0[j-4][k];

for(j=0;j8;j++) //对Ci,Di进行PC-2置换

for(k=0;k6;k++)

subkey[i].key[j][k]=c0_d0[ (pc_2[j][k]-1)/7 ][ (pc_2[j][k]-1)%7 ];

}

}

void DES::IP_Convert()

{

int IP[8][8]={ //初始置换IP矩阵

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

};

cout"你好,你要加密还是解密?加密请按1号键(输入1),解密请按2号键,并确定."'\n';

cinencipher_decipher;

char * s;

if(encipher_decipher==1) s="明文";

else s="密文";

cout"请输入64位"s"(二进制):\n";

int i,j;

for(i=0;i8;i++)

for(j=0;j8;j++)

cintext[i][j];

for(i=0;i8;i++) //进行IP变换

for(j=0;j8;j++)

text_ip[i][j]=text[ (IP[i][j]-1)/8 ][ (IP[i][j]-1)%8 ];

}

用c语言写des加密算法

#include stdio.h #include string.h #include windows.h #include conio.h #include "Schedle.h" class CShift{ public: DWORDLONG mask[16]; int step[16]; CShift(){ for(int i=0;i16;i++){ step[i]=2; mask[i]=0xc000000; } step[0]=step[1]=step[8]=step[15]=1; mask[0]=mask[1]=mask[8]=mask[15]=0x8000000; } }; class CDES{ public: CDES(){ m_dwlKey=0; m_dwlData=0; ConvertTableToMask(dwlKey_PC_1,64); //PrintTable(dwlKey_PC_1,7,8); ConvertTableToMask(dwlKey_PC_2,56); ConvertTableToMask(dwlData_IP,64); ConvertTableToMask(dwlData_Expansion,32); ConvertTableToMask(dwlData_FP,64); ConvertTableToMask(dwlData_P,32); Generate_S(); } void PrintBit(DWORDLONG); void EncryptKey(char *); unsigned char* EncryptData(unsigned char *); unsigned char* DescryptData(unsigned char*); private: void ConvertTableToMask(DWORDLONG *,int); void Generate_S(void); void PrintTable(DWORDLONG*,int,int); DWORDLONG ProcessByte(unsigned char*,BOOL); DWORDLONG PermuteTable(DWORDLONG,DWORDLONG*,int); void Generate_K(void); void EncryptKernel(void); DWORDLONG Generate_B(DWORDLONG,DWORDLONG*); /*For verify schedule permutation only*/ DWORDLONG UnPermuteTable(DWORDLONG,DWORDLONG*,int); /**************************************/ DWORDLONG dwlData_S[9][4][16]; CShift m_shift; DWORDLONG m_dwlKey; DWORDLONG m_dwlData; DWORDLONG m_dwl_K[17]; }; void CDES::EncryptKey(char *key){ printf("\nOriginal Key: %s",key); m_dwlKey=ProcessByte((unsigned char*)key,TRUE); // PrintBit(m_dwlKey); m_dwlKey=PermuteTable(m_dwlKey,dwlKey_PC_1,56); // PrintBit(m_dwlKey); Generate_K(); // printf("\n******************************************\n"); } void CDES::Generate_K(void){ DWORDLONG C[17],D[17],tmp; C[0]=m_dwlKey28; D[0]=m_dwlKey0xfffffff; for(int i=1;i=16;i++){ tmp=(C[i-1]m_shift.mask[i-1])(28-m_shift.step[i-1]); C[i]=((C[i-1]m_shift.step[i-1])|tmp)0x0fffffff; tmp=(D[i-1]m_shift.mask[i-1])(28-m_shift.step[i-1]); D[i]=((D[i-1]m_shift.step[i-1])|tmp)0x0fffffff; m_dwl_K[i]=(C[i]28)|D[i]; m_dwl_K[i]=PermuteTable(m_dwl_K[i],dwlKey_PC_2,48); } } DWORDLONG CDES::ProcessByte(unsigned char *key,BOOL shift){ unsigned char tmp; DWORDLONG byte=0; int i=0; while(i8){ while(*key){ if(byte!=0) byte=8; tmp=*key; if(shift) tmp=1; byte|=tmp; i++; key++; } if(i8) byte=8; i++; } return byte; } DWORDLONG CDES::PermuteTable(DWORDLONG dwlPara,DWOR 基于des算法的rfid安全系统

DLONG* dwlTable,int nDestLen){ int i=0; DWORDLONG tmp=0,moveBit; while(inDestLen){ moveBit=1; if(dwlTable[i]dwlPara){ moveBit=nDestLen-i-1; tmp|=moveBit; } i++; } return tmp; } DWORDLONG CDES::UnPermuteTable(DWORDLONG dwlPara,DWORDLONG* dwlTable,int nDestLen){ DWORDLONG tmp=0; int i=nDestLen-1; while(dwlPara!=0){ if(dwlPara0x01) tmp|=dwlTable[i]; dwlPara=1; i--; } return tmp; } void CDES::PrintTable(DWORDLONG *dwlPara,int col,int row){ int i,j; for(i=0;irow;i++){ printf("\n"); getch(); for(j=0;jcol;j++) PrintBit(dwlPara[i*col+j]); } } void CDES::PrintBit(DWORDLONG bitstream){ char out[76]; int i=0,j=0,space=0; while(bitstream!=0){ if(bitstream0x01) out[i++]='1'; else out[i++]='0'; j++; if(j%8==0){ out[i++]=' '; space++; } bitstream=bitstream1; } out[i]='\0'; strcpy(out,strrev(out)); printf("%s **:%d\n",out,i-space); } void CDES::ConvertTableToMask(DWORDLONG *mask,int max){ int i=0; DWORDLONG nBit=1; while(mask[i]!=0){ nBit=1; nBit=max-mask[i]; mask[i++]=nBit; } } void CDES::Generate_S(void){ int i; int j,m,n; m=n=0; j=1; for(i=0;i512;i++){ dwlData_S[j][m][n]=OS[i]; n=(n+1)%16; if(!n){ m=(m+1)%4; if(!m) j++; } } } unsigned char * CDES::EncryptData(unsigned char *block){ unsigned char *EncrytedData=new unsigned char(15); printf("\nOriginal Data: %s\n",block); m_dwlData=ProcessByte(block,0); // PrintBit(m_dwlData); m_dwlData=PermuteTable(m_dwlData,dwlData_IP,64); EncryptKernel(); // PrintBit(m_dwlData); DWORDLONG bit6=m_dwlData; for(int i=0;i11;i++){ EncrytedData[7-i]=(unsigned char)(bit60x3f)+46; bit6=6; } EncrytedData[11]='\0'; printf("\nAfter Encrypted: %s",EncrytedData); for(i=0;i8;i++){ EncrytedData[7-i]=(unsigned char)(m_dwlData0xff); m_dwlData=8; } EncrytedData[8]='\0'; return EncrytedData; } void CDES::EncryptKernel(void){ int i=1; DWORDLONG L[17],R[17],B[9],EK,PSB; L[0]=m_dwlData32; R[0]=m_dwlData0xffffffff; for(i=1;i=16;i++){ L[i]=R[i-1]; R[i-1]=PermuteTable(R[i-1],dwlData_Expansion,48); //Expansion R EK=R[i-1]^m_dwl_K[i]; //E Permutation PSB=Generate_B(EK,B); //P Permutation R[i]=L[i-1]^PSB; } R[16]=32; m_dwlData=R[16]|L[16]; m_dwlData=PermuteTable(m_dwlData,dwlData_FP,64); } unsigned char* CDES::DescryptData(unsigned char *desData){ int i=1; unsigned char *DescryptedData=new unsigned char(15); DWORDLONG L[17],R[17],B[9],EK,PSB; DWORDLONG dataPara; dataPara=ProcessByte(desData,0); dataPara=PermuteTable(dataPara,dwlData_IP,64); R[16]=dataPara32; L[16]=dataPara0xffffffff; for(i=16;i=1;i--){ R[i-1]=L[i]; L[i]=PermuteTable(L[i],dwlData_Expansion,48); //Expansion L EK=L[i]^m_dwl_K[i]; //E Permutation PSB=Generate_B(EK,B); //P Permutation L[i-1]=R[i]^PSB; } L[0]=32; dataPara=L[0]|R[0]; dataPara=PermuteTable(dataPara,dwlData_FP,64); // PrintBit(dataPara); for(i=0;i8;i++){ DescryptedData[7-i]=(unsigned char)(dataPara0xff); dataPara=8; } DescryptedData[8]='\0'; printf("\nAfter Decrypted: %s\n",DescryptedData); return DescryptedData; } DWORDLONG CDES::Generate_B(DWORDLONG EKPara,DWORDLONG *block){ int i,m,n; DWORDLONG tmp=0; for(i=8;i0;i--){ block[i]=EKPara0x3f; m=(int)(block[i]0x20)4; m|=block[i]0x01; n=(int)(block[i]1)2; block[i]=dwlData_S[i][m][n]; EKPara=6; } for(i=1;i=8;i++){ tmp|=block[i]; tmp=4; } tmp=4; tmp=PermuteTable(tmp,dwlData_P,32); return tmp; } void main(void){ CDES des; des.EncryptKey("12345678"); unsigned char *result=des.EncryptData((unsigned char*)"DemoData"); des.DescryptData(result); }[1]

用C语言来实现DES加密算法（很急）两天内

DES虽然不难但是挺繁复的，代码如下，关键点都有英文解释，仔细看。各个函数的功能都可以从函数名看出来。

#include "pch.h"

#include "misc.h"

#include "des.h"

NAMESPACE_BEGIN(CryptoPP)

/* Tables defined in the Data Encryption Standard documents

* Three of these tables, the initial permutation, the final

* permutation and the expansion operator, are regular enough that

* for speed, we hard-code them. They're here for reference only.

* Also, the S and P boxes are used by a separate program, gensp.c,

* to build the combined SP box, Spbox[]. They're also here just

* for reference.

*/

#ifdef notdef

/* initial permutation IP */

static byte ip[] = {

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 */

static byte fp[] = {

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 byte ei[] = {

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

};

/* The (in)famous S-boxes */

static byte sbox[8][64] = {

/* 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

};

/* 32-bit permutation function P used on the output of the S-boxes */

static byte p32i[] = {

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

};

#endif

/* permuted choice table (key) */

static const byte pc1[] = {

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

};

/* number left rotations of pc1 */

static const byte totrot[] = {

1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28

};

/* permuted choice key (table) */

static const byte pc2[] = {

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

};

/* End of DES-defined tables */

/* bit 0 is left-most in byte */

static const int bytebit[] = {

0200,0100,040,020,010,04,02,01

};

/* Set key (initialize key schedule array) */

DES::DES(const byte *key, CipherDir dir)

: k(32)

{

SecByteBlock buffer(56+56+8);

byte *const pc1m=buffer; /* place to modify pc1 into */

byte *const pcr=pc1m+56; /* place to rotate pc1 into */

byte *const ks=pcr+56;

register int i,j,l;

int m;

for (j=0; j56; j++) { /* convert pc1 to bits of key */

l=pc1[j]-1; /* integer bit location */

m = l 07; /* find bit */

pc1m[j]=(key[l3] /* find which key byte l is in */

bytebit[m]) /* and which bit of that byte */

? 1 : 0; /* and store 1-bit result */

}

for (i=0; i16; i++) { /* key chunk for each iteration */

memset(ks,0,8); /* Clear key schedule */

for (j=0; j56; j++) /* rotate pc1 the right amount */

pcr[j] = pc1m[(l=j+totrot[i])(j28? 28 : 56) ? l: l-28];

/* rotate left and right halves independently */

for (j=0; j48; j++){ /* select bits individually */

/* check bit that goes to ks[j] */

if (pcr[pc2[j]-1]){

/* mask it in if it's there */

l= j % 6;

ks[j/6] |= bytebit[l] 2;

}

}

/* Now convert to odd/even interleaved form for use in F */

k[2*i] = ((word32)ks[0] 24)

| ((word32)ks[2] 16)

| ((word32)ks[4] 8)

| ((word32)ks[6]);

k[2*i+1] = ((word32)ks[1] 24)

| ((word32)ks[3] 16)

| ((word32)ks[5] 8)

| ((word32)ks[7]);

}

if (dir==DECRYPTION) // reverse key schedule order

for (i=0; i16; i+=2)

{

std::swap(k[i], k[32-2-i]);

std::swap(k[i+1], k[32-1-i]);

}

}

/* End of C code common to both versions */

/* C code only in portable version */

// Richard Outerbridge's initial permutation algorithm

/*

inline void IPERM(word32 left, word32 right)

{

word32 work;

work = ((left 4) ^ right) 0x0f0f0f0f;

right ^= work;

left ^= work 4;

work = ((left 16) ^ right) 0xffff;

right ^= work;

left ^= work 16;

work = ((right 2) ^ left) 0x33333333;

left ^= work;

right ^= (work 2);

work = ((right 8) ^ left) 0xff00ff;

left ^= work;

right ^= (work 8);

right = rotl(right, 1);

work = (left ^ right) 0xaaaaaaaa;

left ^= work;

right ^= work;

left = rotl(left, 1);

}

inline void FPERM(word32 left, word32 right)

{

word32 work;

right = rotr(right, 1);

work = (left ^ right) 0xaaaaaaaa;

left ^= work;

right ^= work;

left = rotr(left, 1);

work = ((left 8) ^ right) 0xff00ff;

right ^= work;

left ^= work 8;

work = ((left 2) ^ right) 0x33333333;

right ^= work;

left ^= work 2;

work = ((right 16) ^ left) 0xffff;

left ^= work;

right ^= work 16;

work = ((right 4) ^ left) 0x0f0f0f0f;

left ^= work;

right ^= work 4;

}

*/

// Wei Dai's modification to Richard Outerbridge's initial permutation

// algorithm, this one is faster if you have access to rotate instructions

// (like in MSVC)

inline void IPERM(word32 left, word32 right)

{

word32 work;

right = rotl(right, 4U);

work = (left ^ right) 0xf0f0f0f0;

left ^= work;

right = rotr(right^work, 20U);

work = (left ^ right) 0xffff0000;

left ^= work;

right = rotr(right^work, 18U);

work = (left ^ right) 0x33333333;

left ^= work;

right = rotr(right^work, 6U);

work = (left ^ right) 0x00ff00ff;

left ^= work;

right = rotl(right^work, 9U);

work = (left ^ right) 0xaaaaaaaa;

left = rotl(left^work, 1U);

right ^= work;

}

inline void FPERM(word32 left, word32 right)

{

word32 work;

right = rotr(right, 1U);

work = (left ^ right) 0xaaaaaaaa;

right ^= work;

left = rotr(left^work, 9U);

work = (left ^ right) 0x00ff00ff;

right ^= work;

left = rotl(left^work, 6U);

work = (left ^ right) 0x33333333;

right ^= work;

left = rotl(left^work, 18U);

work = (left ^ right) 0xffff0000;

right ^= work;

left = rotl(left^work, 20U);

work = (left ^ right) 0xf0f0f0f0;

right ^= work;

left = rotr(left^work, 4U);

}

// Encrypt or decrypt a block of data in ECB mode

void DES::ProcessBlock(const byte *inBlock, byte * outBlock) const

{

word32 l,r,work;

#ifdef IS_LITTLE_ENDIAN

l = byteReverse(*(word32 *)inBlock);

r = byteReverse(*(word32 *)(inBlock+4));

#else

l = *(word32 *)inBlock;

r = *(word32 *)(inBlock+4);

#endif

IPERM(l,r);

const word32 *kptr=k;

for (unsigned i=0; i8; i++)

{

work = rotr(r, 4U) ^ kptr[4*i+0];

l ^= Spbox[6][(work) 0x3f]

^ Spbox[4][(work 8) 0x3f]

^ Spbox[2][(work 16) 0x3f]

^ Spbox[0][(work 24) 0x3f];

work = r ^ kptr[4*i+1];

l ^= Spbox[7][(work) 0x3f]

^ Spbox[5][(work 8) 0x3f]

^ Spbox[3][(work 16) 0x3f]

^ Spbox[1][(work 24) 0x3f];

work = rotr(l, 4U) ^ kptr[4*i+2];

r ^= Spbox[6][(work) 0x3f]

^ Spbox[4][(work 8) 0x3f]

^ Spbox[2][(work 16) 0x3f]

^ Spbox[0][(work 24) 0x3f];

work = l ^ kptr[4*i+3];

r ^= Spbox[7][(work) 0x3f]

^ Spbox[5][(work 8) 0x3f]

^ Spbox[3][(work 16) 0x3f]

^ Spbox[1][(work 24) 0x3f];

}

FPERM(l,r);

#ifdef IS_LITTLE_ENDIAN

*(word32 *)outBlock = byteReverse(r);

*(word32 *)(outBlock+4) = byteReverse(l);

#else

*(word32 *)outBlock = r;

*(word32 *)(outBlock+4) = l;

#endif

}

void DES_EDE_Encryption::ProcessBlock(byte *inoutBlock) const

{

e.ProcessBlock(inoutBlock);

d.ProcessBlock(inoutBlock);

e.ProcessBlock(inoutBlock);

}

void DES_EDE_Encryption::ProcessBlock(const byte *inBlock, byte *outBlock) const

{

e.ProcessBlock(inBlock, outBlock);

d.ProcessBlock(outBlock);

e.ProcessBlock(outBlock);

}

void DES_EDE_Decryption::ProcessBlock(byte *inoutBlock) const

{

d.ProcessBlock(inoutBlock);

e.ProcessBlock(inoutBlock);

d.ProcessBlock(inoutBlock);

}

void DES_EDE_Decryption::ProcessBlock(const byte *inBlock, byte *outBlock) const

{

d.ProcessBlock(inBlock, outBlock);

e.ProcessBlock(outBlock);

d.ProcessBlock(outBlock);

}

void TripleDES_Encryption::ProcessBlock(byte *inoutBlock) const

{

e1.ProcessBlock(inoutBlock);

d.ProcessBlock(inoutBlock);

e2.ProcessBlock(inoutBlock);

}

void TripleDES_Encryption::ProcessBlock(const byte *inBlock, byte *outBlock) const

{

e1.ProcessBlock(inBlock, outBlock);

d.ProcessBlock(outBlock);

e2.ProcessBlock(outBlock);

}

void TripleDES_Decryption::ProcessBlock(byte *inoutBlock) const

{

d1.ProcessBlock(inoutBlock);

e.ProcessBlock(inoutBlock);

d2.ProcessBlock(inoutBlock);

}

void TripleDES_Decryption::ProcessBlock(const byte *inBlock, byte *outBlock) const

{

d1.ProcessBlock(inBlock, outBlock);

e.ProcessBlock(outBlock);

d2.ProcessBlock(outBlock);

}

密码学第一次实验报告：DES算法与差分攻击

DES算法与差分攻击

了解DES算法基本工作原理，体会并理解分组密码算法的混淆和扩散概念。了解Sbox工作原理及效果。了解DES的工作模式和填充方式。了解差分攻击

的基本原理。

IP置换目的是将输入的64位数据块按位重新组合，并把输出分为L0、R0两部分，每部分各长32位。

表中的数字代表新数据中此位置的数据在原数据中的位置，即原数据块的第58位放到新数据的第1位，第50位放到第2位，……依此类推，第7位放到第64位。置换后的数据分为L0和R0两部分，L0为新数据的左32位，R0为新数据的右32位。

不考虑每个字节的第8位，DES的密钥由64位减至56位，每个字节的第8位作为奇偶校验位。产生的56位密钥由下表生成（注意表中没有8,16,24，32,40,48,56和64这8位）：

　在DES的每一轮中，从56位密钥产生出不同的48位子密钥，确定这些子密钥的方式如下：

1).将56位的密钥分成两部分，每部分28位。

2).根据轮数，这两部分分别循环左移1位或2位。每轮移动的位数如下表：

移动后，从56位中选出48位。这个过程中，既置换了每位的顺序，又选择了子密钥，因此称为压缩置换。压缩置换规则如下表（注意表中没有9，18，22，25，35，38，43和54这8位）：

压缩后的密钥与扩展分组异或以后得到48位的数据，将这个数据送人S盒，进行替代运算。替代由8个不同的S盒完成，每个S盒有6位输入4位输出。48位输入分为8个6位的分组，一个分组对应一个S盒，对应的S盒对各组进行代替操作。

一个S盒就是一个4行16列的表，盒中的每一项都是一个4位的数。S盒的6个输入确定了其对应的输出在哪一行哪一列，输入的高低两位做为行数H，中间四位做为列数L，在S-BOX中查找第H行L列对应的数据(32)。

S盒代替时DES算法的关键步骤，所有的其他的运算都是线性的，易于分析，而S盒是非线性的，相比于其他步骤，提供了更好安全性

S盒代替运算的32位输出按照P盒进行置换。该置换把输入的每位映射到输出位，任何一位不能被映射两次，也不能被略去，映射规则如下表：

　表中的数字代表原数据中此位置的数据在新数据中的位置，即原数据块的第16位放到新数据的第1位，第7位放到第2位，……依此类推，第25位放到第32位。

末置换是初始置换的逆过程，DES最后一轮后，左、右两半部分并未进行交换，而是两部分合并形成一个分组做为末置换的输入。末置换规则如下表：

置换方法同上

实际应用中，DES是根据其加密算法所定义的明文分组的大小（64bits），将数据割成若干64bits的加密区块，再以加密区块为单位，分别进行加密处理。根据数据加密时每个加密区块间的关联方式，可以分为4种加密模式，包括ECB,CBC,CFB及OFB。

DES算法其中主要起作用的算法有：矩阵置换、扩展、左移、异或、左右互换、s盒作用 。其中对攻击者来说最麻烦的要说s盒一步，破解des体系关键在s盒。 

乍一看六位输入与四位输出貌似没什么关系。但事实上，对于同一个s盒具有相同输入异或的所有输入六比特组的输出四比特异或值有一定规律。 

具体些说，对于输入异或相同的明文对B，B*仅有32组，而这32组输出异或却并不是均匀分布，而是仅分布在很少的几个四比特值中；也可以说具有相同输入异或且输出四比特异或也相同的六比特输入数量不多且分布不均匀。正是这种输入输出输出异或间的不均匀性可以被攻击者利用并破解密钥。

结果表格：

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