Cipher Library

Caesar Cipher

Shift each letter by a fixed number of steps around the alphabet.

Atbash Cipher

Mirror the alphabet so A↔Z, B↔Y, C↔X and so on.

Vigenère Cipher

Use a repeating keyword to apply many Caesar shifts to your message.

Rail Fence Cipher

Write letters in a zig-zag across rails, then read them row by row.

Columnar Transposition

Write the text in rows under a keyword, then read columns in a permuted order.

Intermediate Ciphers

Playfair Cipher

Encrypt pairs of letters using a 5×5 key square built from a keyword.

Hill Cipher

Treat blocks of letters as vectors and encrypt them with matrix multiplication mod 26.

RC4 (Historical Stream Cipher)

A once-popular stream cipher now mostly used as a cautionary example.

ChaCha20 (Modern Stream Cipher)

A fast, modern stream cipher designed to be simple and resistant to timing attacks.

Advanced Ciphers

AES (Advanced Encryption Standard)

Modern standard block cipher that encrypts 128-bit blocks with 128/192/256-bit keys.

DES / 3DES

Earlier block cipher standard; useful for history but no longer secure on its own.

RSA

Asymmetric scheme based on the difficulty of factoring large integers.

Elliptic-Curve Cryptography (ECC)

Public-key techniques built on algebraic curves, giving strong security with shorter keys.

AES-GCM (AES in Galois/Counter Mode)

Combines AES with a counter and a Galois-field MAC to give confidentiality and integrity.

ChaCha20-Poly1305

Pairs the ChaCha20 stream cipher with the Poly1305 message authentication code.

SHA-256 (Cryptographic Hash)

Maps data of any length to a fixed 256-bit digest in a way that is hard to reverse or collide.

Argon2 (Password Hashing)

A modern password hashing algorithm designed to be slow and memory-hard.

Hybrid RSA + AES

Use RSA for keys and AES for bulk data so you get the best of both worlds.