Base32 / Base85 Encoder
Encode or decode text in Base32 or Base85 — the less common encodings you'll still run into in CTFs.
Base32 and Base85 are the less famous relatives of Base64, and each exists for a reason. Base32 uses a case-insensitive alphabet with no easily confused characters, which is why TOTP secrets and onion addresses use it. Base85 packs more data into fewer characters, which is why PDF and Git internals do.
How to use it
- Choose a format and a direction — encode or decode.
- Paste your input.
- Read the converted output.
What to take away
Base32 is built to be typed and spoken
It omits 0, 1 and 8 to avoid confusion with O, I and B, and ignores case. That is why an authenticator app setup key is Base32 and not Base64.
Base85 is roughly 25% denser than Base64
It encodes four bytes as five characters instead of three as four. The cost is an alphabet full of punctuation that needs escaping in many contexts.
Recognise before you decode
All-uppercase letters and digits 2–7 with = padding is Base32. Mixed case with + and / is Base64. Heavy punctuation is likely Base85.
Frequently asked questions
Why do TOTP secrets use Base32?
Because people type and read them aloud during setup. Case-insensitivity and the removal of confusable characters make that far less error-prone than Base64 would be.
Which is better, Base32 or Base64?
Neither — they trade differently. Base32 is longer but robust to human handling; Base64 is more compact and universally supported. Pick by whether a human touches the string.
Is any of this encryption?
No. All of these are reversible by anyone with no key at all. They change representation, never confidentiality.
Where this fits in the course
This security tool pairs with Path 19 — CTF Zone — see all 26 learning paths.
It runs entirely in your browser: nothing is uploaded, no account is needed, and it is free.
Related
- Encoder / Decoder — Base64, URL, and Hex — encode or decode text both ways.
- Hash Identifier — Paste a hash and get likely algorithms, guessed from its length and character set.
- Entropy Calculator — Shannon entropy of any text — a genuine static-analysis signal for spotting packed or encrypted data.
- Cipher Playground — Caesar/ROT, XOR, and Vigenère — the classic ciphers from the CTF zone.