Crypto
Tools
Encrypt • Decrypt • Compute
Classical Cryptography Guide:
• Caesar: Simple shift cipher - enter text and shift value (1-25)
• Affine: Mathematical cipher - 'a' must be coprime to 26 (1,3,5,7,9,11,15,17,19,21,23,25)
• Vigenère: Keyword-based cipher - uses repeating keyword for encryption
• Hill: Matrix cipher - enter 2×2 matrix as comma-separated values (a,b,c,d)
• Prime & coprime: Check if a number is prime, or if two numbers are coprime
• Caesar: Simple shift cipher - enter text and shift value (1-25)
• Affine: Mathematical cipher - 'a' must be coprime to 26 (1,3,5,7,9,11,15,17,19,21,23,25)
• Vigenère: Keyword-based cipher - uses repeating keyword for encryption
• Hill: Matrix cipher - enter 2×2 matrix as comma-separated values (a,b,c,d)
• Prime & coprime: Check if a number is prime, or if two numbers are coprime
Caesar Cipher
A simple substitution cipher that shifts each letter by a fixed number of positions in the alphabet.
Result updates as you change k or text
Learn More About Cryptography
These classical ciphers and number-theory tools form the foundation of modern cryptography. Each has unique properties and historical significance. Click to understand each one's mechanism and mathematical formulas in depth.
Caesar
Simple shift cipher used by Julius Caesar
Affine
Mathematical cipher using modular arithmetic
Vigenère
Polyalphabetic cipher with keyword
Hill
Matrix-based polygraphic cipher