Frequency analysis, bigrams/trigrams, index of coincidence, Shannon entropy.
Heuristic detection for common encodings and hash-like strings.
Identify likely hash algorithms by length and format hints.
Caesar, Vigenère, Atbash, Affine, Rail Fence, Polybius, Morse, T9 and more.
Digraph substitution cipher using a 5x5 key square.
Matrix cipher modulo 26 with invertibility checks.
Keyword-based column ordering transposition cipher.
XOR cipher helper for learning and testing encodings.
Hashing, AES encrypt/decrypt, RSA, PBKDF2, HMAC, signatures.
Derive keys from passwords with iterations and salt.
Inspect X.509 certificates and common fields.
DTMF keypad reference and encoder tools.
Telephone keypad encoder and reference.