# Category: Cryptography

## Cryptography | 3-DES implementation in C

In cryptography, Triple DES (3DES) is a symmetric-key block cipher, which applies the Data Encryption Standard (DES) cipher algorithm three times to each data block.

## Cryptography | DES implementation in C

The Data Encryption Standard (DES) is a symmetric-key algorithm for the encryption of electronic data. Although now considered insecure, it was highly influential in the advancement of modern cryptography.

## Extended Euclidean algorithm Implementation

The extended Euclidean algorithm is an extension to the Euclidean algorithm, which computes, besides the greatest common divisor of integers a and b, the coefficients of Bézout’s identity, that is integers x and y such that ax + by = gcd(a,b)

## Program to find generators of cyclic group

Write a C/C++ program to find generators of cyclic group.   A cyclic group is a group that is generated by a single element. That means that there exists an element g, say, such that every other element of the group can be written as a power of g. This element g is the generator …

## Chinese Remainder Theorem

Write a C/C++ program to solve given simultaneous pairs of Linear Congruence Equations using Chinese remainder theorem.   The Chinese remainder theorem is a theorem which gives a unique solution to simultaneous linear congruences with coprime moduli. In its basic form, the Chinese remainder theorem will determine a number p that, when divided by some …

## Find general solution to given Linear Congruence Equation

Write a C/C++ program to find general solution to given Linear Congruence Equation.

## Solve Simultaneous Pairs of Linear Congruence Equations

Write a C/C++ program to solve given simultaneous pairs of Linear Congruence Equations.

## Find general solution of Linear Diophantine equation

Write a C/C++ program to find general solution of Linear Diophantine equation. A linear Diophantine equation is a first degree (linear) polynomial whose solutions are restricted to integers.

## Vigenère Cipher Implementation

The Vigenère cipher is a form of polyalphabetic substitution to encrypt alphabetic text by using a keyword. The Vigenère cipher is easy to understand and implement. It consists of several Caesar ciphers in sequence with different shift values.

## C program to demonstrate Diffie-Hellman algorithm

Diffie-Hellman algorithm is used to establish a shared secret between two parties which can be used for secret communication for exchanging data over a public network.

## Euclid’s Algorithm to find GCD of two numbers

The Euclid’s algorithm (or Euclidean Algorithm) is a method for efficiently finding the greatest common divisor (GCD) of two numbers. The GCD of two integers X and Y is the largest number that divides both of X and Y (without leaving a remainder).