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encode-decode
Encode and decode text with classical substitution ciphers (Caesar, Vigenère, ROT13/47, Atbash) and modern symmetric ciphers (XOR, RC4, AES-256-GCM) — for learning, CTF puzzles, and classroom cryptography.
Overview
This hub brings together the ciphers people meet in cryptography courses, CTF challenges, and security tutorials. The classical group — Caesar, Vigenère, ROT13, ROT47, and Atbash — shows how substitution worked before computers and is still the fastest way to obfuscate or deobfuscate text. The modern group — XOR, RC4, and AES-256-GCM — shows the stream and symmetric ciphers that real software once used or still uses today. Whether you are decoding a puzzle, checking homework, or comparing why RC4 is broken and AES is not, these tools let you encode and decode side by side without installing anything.
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This hub brings together the ciphers people meet in cryptography courses, CTF challenges, and security tutorials. The classical group — Caesar, Vigenère, ROT13, ROT47, and Atbash — shows how substitution worked before computers and is still the fastest way to obfuscate or deobfuscate text. The modern group — XOR, RC4, and AES-256-GCM — shows the stream and symmetric ciphers that real software once used or still uses today. Whether you are decoding a puzzle, checking homework, or comparing why RC4 is broken and AES is not, these tools let you encode and decode side by side without installing anything.
Only AES-256-GCM. It is authenticated symmetric encryption and is safe for protecting real data. Caesar, Vigenère, ROT13/47, Atbash, XOR, and RC4 are educational or legacy — they are trivially breakable and must never be used to protect anything sensitive.
Caesar shifts every letter by a fixed amount; ROT13 is the special case of a 13-position shift; Atbash mirrors the whole alphabet; ROT47 rotates all printable ASCII (not just letters); and Vigenère uses a repeating keyword so each letter shifts by a different amount, which made it far harder to break historically.
RC4 was once widely used (early TLS, WEP) and still appears in legacy systems and CTF challenges, so being able to encode/decode it is useful for understanding old protocols. It is cryptographically broken and must not be used for new security work — the tool makes that context clear.
Yes. The Caesar Cipher tool runs a brute-force attack that prints all 25 candidate decodings, so the correct plaintext usually stands out by eye when you do not know the shift value.