CryptoTester
Public-key signatures

Sign / Verify

Operation

Sign messages with a private key and verify them with the matching public key. A signature proves authenticity (it came from the key holder) and integrity (it was not altered). Choose classical schemes — Ed25519, ECDSA (including secp256k1, used by Bitcoin and Ethereum), RSA-PSS and DSA — or the post-quantum standards ML-DSA (FIPS 204) and SLH-DSA (FIPS 205).

Generate a key pair in-app or bring your own PEM, sign your message, then flip to Verify; tampering with the message makes verification fail. Post-quantum schemes produce larger signatures but resist attacks from future quantum computers.

Frequently asked questions

What is the difference between signing and encryption?
Encryption hides data; signing proves who created it and that it is unchanged. You sign with your private key, and anyone can verify with your public key.
Which signature scheme should I choose?
Ed25519 is an excellent modern default — fast, small and hard to misuse. Use ECDSA or RSA-PSS for compatibility, and ML-DSA or SLH-DSA when you need post-quantum security.
Are these signatures quantum-safe?
Classical schemes (RSA, ECDSA, Ed25519) are not. ML-DSA and SLH-DSA are NIST-standardised post-quantum signature schemes designed to resist quantum attacks.

Configure

RSA-PSS
SigningRSA signatures with PSS padding (randomised, provably secure) — the recommended RSA signature scheme.
Algorithm

Inputs

Message
0 bytes
Key pair

Signature

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