DES shifrlash algoritmining dasturiy amalga oshirilishi

DES shifrlash algoritmining dasturiy amalga oshirilishi.
DES standartida dastlabki axborot 64 bitli bloklarga ajratiladi va 56 yoki 64
bitli kalit yordamida kriptografik o‘zgartiriladi. Dastlabki axborot bloklari o‘rin
almashtirish va shifrlash funksiyalari yordamida iterasion ishlanadi. Shifrlash
funksiyasini hisoblash uchun 64 bitli kalitdan 48 bitligini olish, 32-bitli kodni 48
bitli kodga kengaytirish, 6-bitli kodni 4-bitli kodga o‘zgartirish va 32-bitli ketma-
ketlikning o‘rnini almashtirish ko‘zda tutilgan.
Rasshifrovka jarayoni shifrlash jarayoniga invers bo‘lib, shifrlashda
ishlatiladigan kalit yordamida amalga oshiriladi.
Hozirda bu standart quyidagi ikkita sababga ko‘ra foydalanishga butunlay
yaroqsiz hisoblanadi:
kalitning uzunligi 56 bitni tashkil etadi, bu shaxsiy kompyuterlarning
zamonaviy rivoji uchun juda kam;
algoritm yaratilayotganida uning apparat usulda amalga oshirilishi
ko‘zda tutilgan edi, ya’ni algoritmda mikroprotsessorlarda bajarilishida ko‘p vaqt
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talab qiluvchi amallar bor edi (masalan, mashina so‘zida ma’lum sxema bo‘yicha
bitlarning o‘rnini almashtirish kabi).
DES algoritmining dasturiy kodi:
# include
# include
# include
# include
//Kalit kiritish jarayoni
int key[64]={
0,0,0,1,0,0,1,1,
0,0,1,1,0,1,0,0,
0,1,0,1,0,1,1,1,
0,1,1,1,1,0,0,1,
1,0,0,1,1,0,1,1,
1,0,1,1,1,1,0,0,
1,1,0,1,1,1,1,1,
1,1,1,1,0,0,0,1
};
//Bloklarga ajratish jarayoni
class Des
{
public:
int keyi[16][48],
total[64],
left[32],
right[32],
ck[28],
dk[28],
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expansion[48],
z[48],
xor1[48],
sub[32],
p[32],
xor2[32],
temp[64],
pc1[56],
ip[64],
inv[8][8];
char final[1000];
void IP();
void PermChoice1();
void PermChoice2();
void Expansion();
void inverse();
void xor_two();
void xor_oneE(int);
void xor_oneD(int);
void substitution();
void permutation();
void keygen();
char * Encrypt(char *);
char * Decrypt(char *);
};
//Boshlang‘ich IP o‘zgartirish
void Des::IP() //Initial Permutation
{
int k=58,i;
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for(i=0;i<32;i++)
{
ip[i]=total[k-1];
if(k-8>0) k=k-8;
else k=k+58;
}
k=57;
for( i=32;i<64;i++)
{
ip[i]=total[k-1];
if(k-8>0) k=k-8;
else k=k+58;
}
}
void Des::PermChoice1() //Permutation Choice-1
{
int k=57,i;
for(i=0;i<28;i++)
{
pc1[i]=key[k-1];
if(k-8>0) k=k-8;
else k=k+57;
}
k=63;
for( i=28;i<52;i++)
{
pc1[i]=key[k-1];
if(k-8>0) k=k-8;
else k=k+55;
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}
k=28;
for(i=52;i<56;i++)
{
pc1[i]=key[k-1];
k=k-8;
}
}
void Des::Expansion() //Expansion Function applied on `right' half
{
int exp[8][6],i,j,k;
for( i=0;i<8;i++)
{
for( j=0;j<6;j++)
{
if((j!=0)||(j!=5))
{
k=4*i+j;
exp[i][j]=right[k-1];
}
if(j==0)
{
k=4*i;
exp[i][j]=right[k-1];
}
if(j==5)
{
k=4*i+j;
exp[i][j]=right[k-1];
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}
}
}
exp[0][0]=right[31];
exp[7][5]=right[0];
k=0;
for(i=0;i<8;i++)
for(j=0;j<6;j++)
expansion[k++]=exp[i][j];
}
void Des::PermChoice2()
{
int per[56],i,k;
for(i=0;i<28;i++) per[i]=ck[i];
for(k=0,i=28;i<56;i++) per[i]=dk[k++];
z[0]=per[13];z[1]=per[16];z[2]=per[10];z[3]=per[23];z[4]=per[0];z[5]
=per[4];z[6]=per[2];z[7]=per[27];
z[8]=per[14];z[9]=per[5];z[10]=per[20];z[11]=per[9];z[12]=per[22];z[
13]=per[18];z[14]=per[11];z[15]=per[3];
z[16]=per[25];z[17]=per[7];z[18]=per[15];z[19]=per[6];z[20]=per[26]
;z[21]=per[19];z[22]=per[12];z[23]=per[1];
z[24]=per[40];z[25]=per[51];z[26]=per[30];z[27]=per[36];z[28]=per[
46];z[29]=per[54];z[30]=per[29];z[31]=per[39];
z[32]=per[50];z[33]=per[46];z[34]=per[32];z[35]=per[47];z[36]=per[
43];z[37]=per[48];z[38]=per[38];z[39]=per[55];
z[40]=per[33];z[41]=per[52];z[42]=per[45];z[43]=per[41];z[44]=per[
49];z[45]=per[35];z[46]=per[28];z[47]=per[31];
}
void Des::xor_oneE(int round) //for Encrypt
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{
int i;
for(i=0;i<48;i++)
xor1[i]=expansion[i]^keyi[round-1][i];
}
void Des::xor_oneD(int round) //for Decrypt
{
int i;
for(i=0;i<48;i++)
xor1[i]=expansion[i]^keyi[16-round][i];
}
void Des::substitution()
{
int s1[4][16]={
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
};
int s2[4][16]={
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
};
int s3[4][16]={
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,
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1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12
};
int s4[4][16]={
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
};
int s5[4][16]={
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
};
int s6[4][16]={
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
};
int s7[4][16]={
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
};
int s8[4][16]={
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,
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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
};
int a[8][6],k=0,i,j,p,q,count=0,g=0,v;
for(i=0;i<8;i++)
{
for(j=0;j<6;j++)
{
a[i][j]=xor1[k++];
}
}
for( i=0;i<8;i++)
{
p=1;q=0;
k=(a[i][0]*2)+(a[i][5]*1);
j=4;
while(j>0)
{
q=q+(a[i][j]*p);
p=p*2;
j--;
}
count=i+1;
switch(count)
{
case 1:
v=s1[k][q]; break;
case 2:
v=s2[k][q]; break;
case 3:
v=s3[k][q]; break;
case 4:
v=s4[k][q]; break;
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case 5:
v=s5[k][q]; break;
case 6:
v=s6[k][q]; break;
case 7:
v=s7[k][q]; break;
case 8:
v=s8[k][q]; break;
}
int d,i=3,a[4];
while(v>0)
{
d=v%2;
a[i--]=d;
v=v/2;
}
while(i>=0)
{
a[i--]=0;
}
for(i=0;i<4;i++)
sub[g++]=a[i];
}
}
void Des::permutation()
{
p[0]=sub[15];p[1]=sub[6];p[2]=sub[19];p[3]=sub[20];p[4]=sub[28];p[
5]=sub[11];p[6]=sub[27];p[7]=sub[16];
p[8]=sub[0];p[9]=sub[14];p[10]=sub[22];p[11]=sub[25];p[12]=sub[4];
p[13]=sub[17];p[14]=sub[30];p[15]=sub[9];
p[16]=sub[1];p[17]=sub[7];p[18]=sub[23];p[19]=sub[13];p[20]=sub[3
1];p[21]=sub[26];p[22]=sub[2];p[23]=sub[8];
p[24]=sub[18];p[25]=sub[12];p[26]=sub[29];p[27]=sub[5];p[28]=sub[
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21];p[29]=sub[10];p[30]=sub[3];p[31]=sub[24];
}
void Des::xor_two()
{
int i;
for(i=0;i<32;i++)
{
xor2[i]=left[i]^p[i];
}
}
void Des::inverse()
{
int p=40,q=8,k1,k2,i,j;
for(i=0;i<8;i++)
{
k1=p;k2=q;
for(j=0;j<8;j++)
{
if(j%2==0)
{
inv[i][j]=temp[k1-1];
k1=k1+8;
}
else if(j%2!=0)
{
inv[i][j]=temp[k2-1];
k2=k2+8;
}
}
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p=p-1;q=q-1;
}
}
char * Des::Encrypt(char *Text1)
{
int i,a1,j,nB,m,iB,k,K,B[8],n,t,d,round;
char *Text=new char[1000];
strcpy(Text,Text1);
i=strlen(Text);
int mc=0;
a1=i%8;
if(a1!=0) for(j=0;j<8-a1;j++,i++) Text[i]=' '; Text[i]='\0';
keygen();
for(iB=0,nB=0,m=0;m<(strlen(Text)/8);m++) //Repeat for
TextLenth/8 times.
{
for(iB=0,i=0;i<8;i++,nB++)
{
n=(int)Text[nB];
for(K=7;n>=1;K--)
{
B[K]=n%2; //Converting 8-Bytes to 64-bit Binary Format
n/=2;
} for(;K>=0;K--) B[K]=0;
for(K=0;K<8;K++,iB++) total[iB]=B[K]; //Now `total' contains the
64-Bit binary format of 8-Bytes
}
IP(); //Performing initial permutation on `total[64]'
for(i=0;i<64;i++) total[i]=ip[i]; //Store values of ip[64] into total[64]
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for(i=0;i<32;i++) left[i]=total[i]; //
+--> left[32]
// total[64]--|
for(;i<64;i++) right[i-32]=total[i];// +--> right[32]
for(round=1;round<=16;round++)
{
Expansion(); //Performing expansion on `right[32]' to get
`expansion[48]'
xor_oneE(round); //Performing XOR operation on
expansion[48],z[48] to get xor1[48]
substitution();//Perform substitution on xor1[48] to get sub[32]
permutation(); //Performing Permutation on sub[32] to get p[32]
xor_two(); //Performing XOR operation on left[32],p[32] to get
xor2[32]
for(i=0;i<32;i++) left[i]=right[i]; //Dumping right[32] into left[32]
for(i=0;i<32;i++) right[i]=xor2[i]; //Dumping xor2[32] into right[32]
}
for(i=0;i<32;i++) temp[i]=right[i]; // Dumping -->[ swap32bit ]
for(;i<64;i++) temp[i]=left[i-32]; // left[32],right[32] into temp[64]
inverse(); //Inversing the bits of temp[64] to get inv[8][8]
/* Obtaining the Cypher-Text into final[1000]*/
k=128; d=0;
for(i=0;i<8;i++)
{
for(j=0;j<8;j++)
{
d=d+inv[i][j]*k;
k=k/2;
}
final[mc++]=(char)d;
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k=128; d=0;
}
} //for loop ends here
final[mc]='\0';
return(final);
}
char * Des::Decrypt(char *Text1)
{
int i,a1,j,nB,m,iB,k,K,B[8],n,t,d,round;
char *Text=new char[1000];
unsigned char ch;
strcpy(Text,Text1);
i=strlen(Text);
keygen();
int mc=0;
for(iB=0,nB=0,m=0;m<(strlen(Text)/8);m++) //Repeat for
TextLenth/8 times.
{
for(iB=0,i=0;i<8;i++,nB++)
{
ch=Text[nB];
n=(int)ch;//(int)Text[nB];
for(K=7;n>=1;K--)
{
B[K]=n%2; //Converting 8-Bytes to 64-bit Binary Format
n/=2;
} for(;K>=0;K--) B[K]=0;
for(K=0;K<8;K++,iB++) total[iB]=B[K]; //Now `total' contains the
64-Bit binary format of 8-Bytes
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}
IP(); //Performing initial permutation on `total[64]'
for(i=0;i<64;i++) total[i]=ip[i]; //Store values of ip[64] into total[64]
for(i=0;i<32;i++) left[i]=total[i]; //
+--> left[32]
// total[64]--|
for(;i<64;i++) right[i-32]=total[i];// +--> right[32]
for(round=1;round<=16;round++)
{
Expansion(); //Performing expansion on `right[32]' to get
`expansion[48]'
xor_oneD(round);
substitution();//Perform substitution on xor1[48] to get sub[32]
permutation(); //Performing Permutation on sub[32] to get p[32]
xor_two(); //Performing XOR operation on left[32],p[32] to get
xor2[32]
for(i=0;i<32;i++) left[i]=right[i]; //Dumping right[32] into left[32]
for(i=0;i<32;i++) right[i]=xor2[i]; //Dumping xor2[32] into right[32]
} //rounds end here
for(i=0;i<32;i++) temp[i]=right[i]; // Dumping -->[ swap32bit ]
for(;i<64;i++) temp[i]=left[i-32]; // left[32],right[32] into temp[64]
inverse(); //Inversing the bits of temp[64] to get inv[8][8]
/* Obtaining the Cypher-Text into final[1000]*/
k=128; d=0;
for(i=0;i<8;i++)
{
for(j=0;j<8;j++)
{
d=d+inv[i][j]*k;
k=k/2;
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}
final[mc++]=(char)d;
k=128; d=0;
}
} //for loop ends here
final[mc]='\0';
char *final1=new char[1000];
for(i=0,j=strlen(Text);i
final1[i]=final[j]; final1[i]='\0';
return(final);
}
int main()
{
Des d1,d2;
char *str=new char[1000];
char *str1=new char[1000];
//strcpy(str,"PHOENIX it & ece solutions.");
cout<<"Enter a string : ";
gets(str);
str1=d1.Encrypt(str);
cout<<"\ni/p Text: "<
cout<<"\nCypher : "<
//
ofstream fout("out2_fil.txt"); fout<
cout<<"\no/p Text: "<
return 0;
}
// Kalit generatsiyasi jarayoni
void Des::keygen()
{
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PermChoice1();
int i,j,k=0;
for(i=0;i<28;i++)
{
ck[i]=pc1[i];
}
for(i=28;i<56;i++)
{
dk[k]=pc1[i];
k++;
}
int noshift=0,round;
for(round=1;round<=16;round++)
{
if(round==1||round==2||round==9||round==16)
noshift=1;
else
noshift=2;
while(noshift>0)
{
int t;
t=ck[0];
for(i=0;i<28;i++)
ck[i]=ck[i+1];
ck[27]=t;
t=dk[0];
for(i=0;i<28;i++)
dk[i]=dk[i+1];
dk[27]=t;
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noshift--;
}
PermChoice2();
for(i=0;i<48;i++)
keyi[round-1][i]=z[i];
}
}
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