Cryptography Tool

A C console application implementing Caesar Cipher and Double Fence encryption algorithms.

Description

This program provides two classical encryption methods: Caesar Cipher (shift cipher) and Double Fence (rail fence) cipher. Users can encrypt text using either method, demonstrating fundamental cryptographic techniques.

Features

• Caesar Cipher Encryption: Shifts letters by a specified key value
  • Preserves letter case (uppercase/lowercase)
  • Handles wraparound (Z+1 → A)
  • Non-alphabetic characters remain unchanged
• Double Fence Encryption: Alternates characters between two strings
  • Splits input into even and odd positions
  • Concatenates for encrypted output
• Character Handling: Works with both uppercase and lowercase letters
• ASCII Manipulation: Direct character code arithmetic

Technologies Used

• C Programming Language
• <stdio.h> for I/O
• <string.h> for string manipulation
• <stdlib.h> for utilities
• Character array manipulation
• Visual Studio project structure

Encryption Methods

Caesar Cipher

Shifts each letter by a fixed number of positions in the alphabet. Example with key=3:

• "HELLO" → "KHOOR"
• "abc" → "def"

Double Fence

Splits characters into two groups (even/odd positions) and concatenates. Example:

• "HELLO" → "HLOEL" (positions 0,2,4 + positions 1,3)

Building and Running

Prerequisites

• C compiler (Visual Studio recommended)
• Windows operating system

Build Instructions

1. Open the solution file in Visual Studio
2. Build the solution (F7 or Build > Build Solution)
3. Run the executable or press F5

Author

Christian Burnett