Encryption and Decryption using a c program

encryption is process through which we can change a text into a coded language  with this method we can hide data for unwanted users and  used for security purpose. in networking our data transfer from one end to another using this encryption and decryption .decryption means to decode the previously coded message.
here in this program we are just adding a integer 2 value in each character of the given message and for decoding we are just subtracting 2 from the previously coded message.

#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
char str[50];
int i,x;
       do{

printf("press 1.Encryption \n 2.Decryption\n3.exit\n");
scanf("%d",&x);

clrscr();

       switch(x)
       {

case 1:


puts("Enter your message\n");
gets(str);
  printf("encrypted message is here:\n");
for(i=0;str[i]!='\0';i++)
{
      str[i]=str[i]+2 ;
     printf("%c",str[i]);
}
printf("\n");

break;
case 2:
printf("Dencrypted message is here:\n");
for(i=0;str[i]!='\0';i++)
{
      str[i]=str[i]-2 ;
     printf("%c",str[i]);

}
printf("press any key to continue");
getch();

printf("\n");
break;


}

}while(x!=3);


}

Comments

Post a Comment

Popular posts from this blog

Pre-compiled Headers

A precompiled header is a (c and c++) header that is compiled into intermediate form that is faster to process for the computer. Turbo C++ can generate (and subsequently use) pre-compiled headers for your projects.   Pre-compiled headers are header files that are compiled once, then used over and over again in their compiled state.  Using Pre-compiled Headers To control the use of pre-compiled headers, do one of the following:   1) Turn on the [X] Pre-compiled Headers option in the Options -> Compiler->  Code Generation dialog box.   The IDE bases the name of the pre-compiled header file on the project name, creating <project>.SYM   2) Use the - H, -H=<filename>, and -Hu command-line options with TCC.EXE.   3) Use the hdrfile and hdrstop pragmas inside your code.    Code Generation dialog box t his dialog box is where you select the memory model you'll be using and any options you find necessary for the type of code you want to generate
Read more

CONNECTING WITH FTP-FILE TRANSFER PROTOCOL

With FTP we can send files attached to e-mail ,but this is inefficient  and wastes resources if the files are large. Instead there’s FTP a method of retrieving files from and sending files to others computers on the net. Ideally, FTP will be built into windows and MAC operating systems some day (as it already is for unix) , so that managing files on the internet will be easy as managing files on your own computer. The typical FTP session starts when you run the FTP program and connect to an FTP site . depending on the program and connect to an FTP site. Depending on the program you have, you’ll eitherenter your login information before connecting or you’ll be premoted to do it after you connect. If you’re using a web browser to connect to an anonymous site, the browser.  Connecting with FTP May  prompt you to log in, though most send your e-mail address as the password automatically, these general steps illustrate a typical FTP session: 1.        Start your software o
Read more

PROBING THE INTERNET WITH TELNET:

One aspect of the interconnectedness of the NET is that you can log in to other machines on the internet directly from from your own computer,no matter where you are.with TELNET you can log onto any computer  or network thousands of public sites where passwords are not required .you would not be able to work on these unix systems without telnet, which turns your windows or macnitosh computer into a remote terminal that is compatible with computers outside of the personal computer universe. Many university and public libraries make their catalog available by telnet,as do countlass other repositories of useful information. After you have started your telnet program, you need to open a internet connection and log in to the site with the steps described here: Type telnet and press enter at the unix prompt. This will put you at a telnet> prompt. then type open host site name and press enter. Logging in with telnet is the same as logging in to any computer system.
Read more