Classical Ciphers

Encrypt and decrypt text with four pre-computer ciphers: Atbash (the Hebrew letter-reversal cipher, self-reciprocal), ROT47 (rotates printable ASCII by 47, self-reciprocal — a wider variant of ROT13), Affine (E(x) = ax + b mod 26), and the Rail Fence transposition cipher. Each shows its transform and is invertible. Nothing leaves your browser.