Digital Signature Verifier

Verify RSA and ECDSA digital signatures — all processing done in your browser

🔒 Privacy first: All cryptographic operations use the browser's Web Crypto API. No keys, messages, or signatures are ever sent to a server.

Algorithm

Signature Algorithm

RSA PKCS#1 v1.5 is the most widely deployed signature scheme. Used in TLS, JWT (RS256), code signing, and many other applications.

Public Key (PEM)

Public Key

📁 Load from file

Message

Message Content

Message (hex encoded)

Lowercase or uppercase hex, with or without spaces

Message (base64 encoded)

Message File 📁 Choose file to verify

Signature

Encoding

Signature

Algorithm Reference

RSA-PKCS1-v1_5 — Classic RSA signature scheme. Used in TLS 1.2 and below, JWT RS256/RS384/RS512.
RSA-PSS — Probabilistic RSA signature with better security proofs. Used in TLS 1.3, modern applications.
ECDSA — Elliptic Curve signature. Smaller keys with equivalent security. Used in JWT ES256/ES384/ES512, Bitcoin, TLS 1.3.

Public Key Format: PKCS#8 SubjectPublicKeyInfo (BEGIN PUBLIC KEY). Not PKCS#1 (BEGIN RSA PUBLIC KEY).
To convert: openssl rsa -in private.pem -pubout -out public.pem