Public-key

RSA-PSS sign & verify

Sign with real RSA-PSS, choose the salt length, then open the signature with the public key to see the encoded message, the recovered salt, and which check fails when you tamper with it.

What's happening under the hood →·Read the RSA padding: OAEP, PKCS#1 v1.5, and why raw RSA fails module for the full explanation →·See the Code signing: proving who shipped a binary, and what it can't prove use case →·See the Secure boot: a chain of signatures from the first instruction to the OS use case →

1. Generate a key pair

A real RSA key pair with e = 65537. 4096-bit keys can take a few seconds.

Modulus size

Hash (message and MGF1)

2. Sign a message

Message

Salt length (bytes)0 to 222; the hash length is the usual choice

3. Verify: edit the message, signature, or salt length, or swap the key

Message to verify

Signature (hex)

Expected salt length (bytes)