C++简单数据加密算法实现加密和解密的代码
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This is a program for Encryption and Decryption
This program uses the Simple Data Encryption Standard (SDES) Algorithm.
This Algo takes 8-bits of plaintext at a time and produces 8-bits of ciphertext.
It uses 10-bits of key for Encryption and Decryption.
Developed by : Vivek Kumar ([email protected])
Created on : 31 March 2005
Last Modified on : 10 April 2005
Any sort of suggetions/comments are most welcome at [email protected]
#include
#include
#include
#include
#include
#include
void menuEn();
void menuDe();
int DoEnDe(int);
class SDES
{
private:
char KEY[11],K1[9],K2[9],IPOutput[9],InvIPOutput[9];
char F1Output[9],F2Output[9];
char INPUT_BIT[9],OUTPUT_BIT[9];
public:
unsigned char INPUT,OUTPUT;
~SDES();
void GenerateKeys();
void conv_to_bits(unsigned char );
void DES_Encryption(unsigned char );
void DES_Decryption(unsigned char );
void SDES::GetChar();
};
{
int i;
{
printf("nInValid Key-Length %s %d",key,strlen(key));
getch();
exit(1);
}
{
KEY[i]=key[i];
}
KEY[10]='0';
}
void SDES::GenerateKeys()
{
int i;
for (i=0;i<10;i++)
P10_OP[i]=KEY[P10[i]-1];
P10_OP[10]='0';
for (i=0;i<5;i++)
{
P10LEFT[i]=P10_OP[i];
P10RIGHT[i]=P10_OP[i+5];
}
P10LEFT[5]='0';
P10RIGHT[5]='0';
pl=new char[6];
pr=new char[6];
pl=Left_Shift(P10LEFT,1);
pr=Left_Shift(P10RIGHT,1);
for (i=0;i<5;i++)
{
plpr[i]=pl[i];
plpr[i+5]=pr[i];
}
plpr[10]='0';
for (i=0;i<8;i++)
K1[i]=plpr[P8[i]-1];
pl1=Left_Shift(pl,2);
pr1=Left_Shift(pr,2);
for (i=0;i<5;i++)
{
plpr[i]=pl1[i];
plpr[i+5]=pr1[i];
}
plpr[10]='0';
for (i=0;i<8;i++)
{
K2[i]=plpr[P8[i]-1];
}
}
{
int length=strlen(bs);
char_ptr = new char[length +1];
str=new char[length+1];
char_ptr=bs;
int i,j;
for (j=0;j=0;i--)
{
bit=ch%2;
ch=ch/2;
if (bit!=0)
INPUT_BIT[i]='1';
else
INPUT_BIT[i]='0';
}
}
{
int IPArray[8]={2,6,3,1,4,8,5,7};
int i;
IPOutput[8]='0';
for (i=0;i<8;i++)
{
IPOutput[i]=input[IPArray[i]-1];
}
}
{
int InvIPArray[8]={4,1,3,5,7,2,8,6};
int i;
InvIPOutput[8]='0';
for (i=0;i<8;i++)
{
InvIPOutput[i]=input[InvIPArray[i]-1];
}
}
void SDES::DES_Encryption(unsigned char input)
{
char LIP[5],RIP[5],L1[5],R1[5];
int i;
INPUT=input;
printf("nEncrpyting.........");
for (i=0;i<4;i++)
{
LIP[i]=IPOutput[i];
RIP[i]=IPOutput[i+4];
}
LIP[4]='0';
RIP[4]='0';
Function_F(LIP,RIP,1);
for (i=0;i<4;i++)
{
L1[i]=F1Output[i];
R1[i]=F1Output[4+i];
}
L1[4]='0';
R1[4]='0';
Function_F(R1,L1,2);
GetChar();
}
Here IP, InvIP, E/P, SBOX1 and SBOX2 are same
But Function_F first operats on sub-key K2 and
void SDES::DES_Decryption(unsigned char input)
{
char LIP[5],RIP[5],L1[5],R1[5];
int i;
INPUT=input;
conv_to_bits(INPUT);
printf("nDecrpyting.........");
for (i=0;i<4;i++)
{
LIP[i]=IPOutput[i];
RIP[i]=IPOutput[i+4];
}
LIP[4]='0';
RIP[4]='0';
Function_F(LIP,RIP,2);
for (i=0;i<4;i++)
{
L1[i]=F1Output[i];
R1[i]=F1Output[4+i];
}
L1[4]='0';
R1[4]='0';
Function_F(R1,L1,1);
InvIP(F1Output);
GetChar();
}
{
int i;
char SBOX_Output[5];
char P4_Output[5];
char fk_Output[5];
char Main_Output[9];
for (i=0;i<8;i++)
{
E_POutput[i]=rinput[E_P[i]-1];
}
E_POutput[8]='0';
EXOR_Output=EX_OR(E_POutput,key);
LEXOR=new char[strlen(EXOR_Output)/2+1];
REXOR=new char[strlen(EXOR_Output)/2+1];
for (i=0;i8)
{
printf("nWRONG LENGTH STRING");
exit(0);
}
for (i=0;i<8;i++)
{
if (bs[i]=='1')
{
in=1;
for (j=1;j<8-i;j++)
{
}
ch=ch+in;
}
}
OUTPUT=ch;
}
SDES::~SDES()
{
}
void main(void)
{
unsigned char ch,ch1;
int i,n=10,choice;
while (1)
{
key = new char[11];
sfname = new char[20];
tfname = new char[20];
mainmenu(&choice);
fflush(stdin);
switch (choice)
{
case 1:
menuEn();
DoEnDe(choice);
break;
case 2:
menuDe();
DoEnDe(choice);
break;
case 3:
exit(0);
default:
printf("nWrong Choice Enter againnPress any key to return to Main Menu..");
getch();
break;
}
}
}
{
printf("nWhat do you want to do..");
printf("n1. Encryption");
printf("n2. Decryption");
printf("n3. Exit");
printf("nnEnter the choice? ");
scanf("%d",c);
}
void menuEn()
{
sfname=new char[20];
tfname=new char[20];
key=new char[11];
printf("nEncryption Menunn");
printf("nEnter the filename to be Encrypted: ");
gets(sfname);
printf("nEnter the Target file name: ");
gets(tfname);
printf("nEnter the 10-bits KEY: ");
gets(key);
printf("nnNotedown this key, as same key is used for Decryption");
}
void menuDe()
{
sfname=new char[20];
tfname=new char[20];
key=new char[11];
printf("nDecryption Menunn");
printf("nEnter the filename to be Decrypted: ");
gets(sfname);
printf("nEnter the Target file name: ");
gets(tfname);
printf("nEnter the 10-bits KEY: ");
gets(key);
}
int DoEnDe(int c)
{
SDES S(key);
int i,n;
unsigned char ch;
fp=fopen(tfname,"w");
ft=fopen(sfname,"r");
if (fp==NULL)
{
printf("nTarget File not opened SORRY");
getch();
fclose(fp);
return(0);
}
if (ft==NULL)
{
printf("nSource File not opened SORRY");
getch();
fclose(ft);
return(0);
}
while (fread(&ch,1,1,ft)==1)
{
S.OUTPUT=ch;
for (i=0;i