The tokens, codes and signatures
toolbox.
Generate one-time codes, check a JWT signature, compute CRCs and hashes, and read UUIDs, all without sending a secret anywhere.
Keep this toolbox for offline use
12 useful places to start.
Secrets are typed into your own browser and never leave it. Verify what you paste, since a token you can read is not a token you can trust.
TOTP and HOTP code generator
Work out the RFC 6238 TOTP or RFC 4226 HOTP one-time code for a secret and a time or counter you type, with the otpauth URI.
JWT signature verifier (HS256, RS256, ES256)
Check a JWT’s signature with an HMAC secret, JWK or PEM public key, and its exp and nbf claims at a time you choose, on your device.
JWT decoder
Inspect a JSON Web Token’s header and payload locally.
HMAC generator
Compute an HMAC-SHA-256, SHA-1, SHA-384 or SHA-512 message authentication code with a secret key, on your device.
SHA hash generator
Create SHA-256, SHA-384 or SHA-512 hashes of text.
File hash calculator and verifier
Work out the MD5, SHA-1, SHA-256, SHA-384, SHA-512 or CRC-32 of files or text, and check them against a published checksum.
CRC calculator (CRC-8, CRC-16, CRC-32, CRC-64 and custom)
Compute any of the 113 catalogued CRCs, or your own width, polynomial and reflection, of text or hex bytes, with the check value.
MD5, SHA-1, CRC-32 and Adler-32 generator
Compute classic checksums for text or hex bytes without uploading anything.
UUID and ULID inspector
Decode a UUID of any version or a ULID: version, variant, embedded timestamp in UTC, clock sequence, node and every common spelling.
UUID generator
Generate random version 4 UUIDs.
Base32, Base58, Base62 and Base85 encoder and decoder
Encode text or bytes as Base16, Base32, Crockford, Base58 or Base58Check, Base62, Ascii85 or Z85, and decode them back with exact error positions.
Base64 encoder & decoder
Encode Unicode text to Base64, or decode it back.
A few things you
can tick off.
- Check a TOTP code against a secret
- Verify an HS256 or RS256 token
- Compare a download with its published SHA-256