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Displaying  Source Code(s)  
 

 
File Encryption Program in C.

--------------------------------------------------------------------------------

Description : A not So simple program that demonstrates the usage of
functions, points, arrays, and file I/O. Has one problem, will leave a
random character at the end of the decrypted file, but other than that, it
works fine.

/* WARNING : do not give the have the same sourcefile and
destinationfile, encrypting or decrypting, this bug will be worked
out as i get more interested in file encryption
*/

#include <stdio.h>

#define ENCRYPTION_FORMULA (int) Byte + 25
#define DECRYPTION_FORMULA (int) Byte - 25

int Encrypt(char * FILENAME, char * NEW_FILENAME)
{
//printf("Loaded Encrypt<BR>);
FILE *inFile; //Declare inFile
FILE *outFile; //Declare outFile

char Byte;
char newByte;
int n;


printf("1");
int i=0;

inFile = fopen(FILENAME,"rb");
outFile = fopen(NEW_FILENAME, "w");

if(inFile==NULL)
printf("Error: Can't Open inFile");

if(outFile==NULL)
{
printf("Error: Can't open outFile.<BR>);
return 1;
}
else
{

printf("File Opened, Encrypting");
while(1)
{
printf(".");


if(Byte!=EOF)
{
Byte=fgetc(inFile);
// printf("%d",Byte);
newByte=Byte+25;

fputc(newByte,outFile);

}

else
{
printf("
End of File");
break;
}
}
fclose(inFile);
fclose(outFile);

}
}

int Decrypt (char *FILENAME, char *NEW_FILENAME)
{
//printf("Loaded Decrypt<BR>);
FILE *inFile; //Declare inFile
FILE *outFile; //Declare outFile

char Byte;
char newByte;
printf("2");
int i=0;

inFile = fopen(FILENAME,"rb");
outFile = fopen(NEW_FILENAME, "w");

if(inFile==NULL)
printf("Error: Can't Open inFile");

if(outFile==NULL)
{
printf("Error: Can't open outFile.<BR>);
return 1;
}
else
{

printf("File Opened, Decrypting");
while(1)
{
printf(".");


if(Byte!=EOF)
{
Byte=fgetc(inFile);
// printf("%d",Byte);
newByte=Byte-25;

fputc(newByte,outFile);

}

else
{
printf("
End of File");
break;
}
}
fclose(inFile);
fclose(outFile);

}
}

int main()
{
char encFile[200];
char newencFile[200];
char decFile[200];
char newdecFile[200];

int choice;

printf("NOTE: you must Decrypt the file with the same file
extension!!!<BR>);
printf("Enter 1 to Encrypt / 2 to Decrypt<BR>);
scanf("%d",&choice);

switch(choice)
{
case 1:
printf("Enter the Source Filename: ");
scanf("%s",&encFile);
printf("Enter the Destination Filename: ");
scanf("%s",&newencFile);
Encrypt(encFile, newencFile);
break;
case 2:
printf("Enter the Source Filename: ");
scanf("%s",&decFile);
printf("Enter the Destination Filename: ");
scanf("%s",&newdecFile);
Decrypt(decFile, newdecFile);
break;

}

return 0;
}

 

 

 

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