Skip to main content

Introduction to Basic Encryption and Decryption

Encryption is a familiar sounding word which means to convert readable data in such a form that it becomes un-understandable or un-meaningful. It is employed almost everywhere where any confidential data is needed to be kept or transferred.

Encryption goes hand in hand with decryption which means to convert un-meaningful encrypted data to its original meaningful form.

Here in this article we are going to design two functions, one for encryption and other for decryption, to illustrate the basic concept of encryption and decryption.

Please note that the example program provided in this article is for illustrative purpose only, there are a few limitations in the program which limits its practical use.

How encryption and decryption works?

The main concept behind encryption is to convert the readable data into something which looks un-meaningful to us. It could be achieved in various ways but the simplest one is to change the ASCII code of the data.

Ex.

  #include<iostream.h>

  void main(void)
  {
   int i;
   char str[20]="I like C++";

   for(i=0;str[i]!='\0';i++)
     str[i]+=10;

   cout<<"Encrypted:\n";
   cout<<str;
   cout<<endl<<endl;

   for(i=0;str[i]!='\0';i++)
     str[i]-=10;

   cout<<"Decrypted:\n";
   cout<<str;
   cout<<endl;
  }

OUTPUT:

   Encrypted:
   S*vsuo*M55
   Decrypted:
   I like C++
   Press any key to continue

In the above example we increased the ASCII code of each character of the string by 10, notice how un-meaningful the encrypted data looks!

While decrypting we need to reverse the process by decreasing the ASCII code of each character by 10, which would give us the original data.

This concept will form the basis of encryption and decryption in for our program which is listed below:

  // A simple c++ program to
  // illustrate basic encryption
  // and decryption
  #include<iostream.h>

  #define FACTOR 95

  void encrypt(char *);
  void decrypt(char *);

  void main(void)
  {
   char str[20]="I like C++";

   cout<<"Original String:\n";
   cout<<str;
   cout<<endl<<endl;

   encrypt(str);

   cout<<"After Encryption:\n";
   cout<<str;
   cout<<endl<<endl;;

   cout<<"After Decryption:\n";
   decrypt(str);
   cout<<str;
   cout<<endl;
  }

  void encrypt(char *str)
  {
   while(*str!='\0')
   {
    *str+=FACTOR;
    str++;
   }
  }

  void decrypt(char *str)
  {
   while(*str!='\0')
   {
    *str-=FACTOR;
    str++;
   }
  }

Good-Bye!

Related Articles:

Popular posts from this blog

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {      // } //*/ //* Toggle line if ( 2 ) {      // } else {      // } //*/ Now see how easy it is to toggle a part of PHP code by just removing or adding a single " / " from th

Introduction to Operator Overloading in C++

a1 = a2 + a3; The above operation is valid, as you know if a1, a2 and a3 are instances of in-built Data Types . But what if those are, say objects of a Class ; is the operation valid? Yes, it is, if you overload the ‘+’ Operator in the class, to which a1, a2 and a3 belong. Operator overloading is used to give special meaning to the commonly used operators (such as +, -, * etc.) with respect to a class. By overloading operators, we can control or define how an operator should operate on data with respect to a class. Operators are overloaded in C++ by creating operator functions either as a member or a s a Friend Function of a class. Since creating member operator functions are easier, we’ll be using that method in this article. As I said operator functions are declared using the following general form: ret-type operator#(arg-list); and then defining it as a normal member function. Here, ret-type is commonly the name of the class itself as the ope