ES384 JWT Decoder & Verifier
Paste an ES384-signed JWT to decode its claims. Enter the ECDSA P-384 public key (PEM or JWK) to verify the signature — 192-bit security level, verified locally in your browser.
100% in-browser — nothing uploadedEncoded JWT
Decoded Header
Paste a token to decode this segment.
Decoded Payload
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Verify Signature
Features
100% private
Your token is decoded entirely in your browser. Nothing is uploaded, logged, or sent to any server or API.
Instant decoding
Paste a JWT and the header, payload, and claims are decoded in real time — no button required.
Human-readable claims
Standard claims like exp, iat, and nbf are explained and shown as readable dates with expiry status.
Signature verification
Verify HS256/384/512 with a secret, or RS, PS, and ES algorithms with a public key — all client-side.
What is ES384 in a JWT?
ES384 is ECDSA using the P-384 elliptic curve with SHA-384. It provides 192 bits of security — significantly more than ES256's 128 bits — using larger but still compact EC keys. P-384 keys are 48 bytes per coordinate and produce 96-byte signatures in JWTs. This makes ES384 considerably more compact than RSA alternatives with similar or higher security.
ES384 is recommended by NIST for use beyond 2030 in systems requiring long-term security. It is used in government and financial systems that mandate higher security margins. For most commercial web applications, ES256 provides sufficient security; ES384 is chosen when a 192-bit security level is specifically required.
Verify an ES384 JWT above by pasting the token and entering the P-384 public key in PEM or JWK format. The JWK for a P-384 key has kty: EC and crv: P-384. Verification uses the browser's Web Crypto API with ECDSA-SHA-384 — no data is sent to any server.
ES384 at a glance
- Full name
- ECDSA using P-384 and SHA-384
- Algorithm family
- ECDSA (asymmetric)
- Curve
- P-384 (secp384r1)
- Key size
- 384-bit EC key (48 bytes per coordinate)
- Signature size
- 96 bytes (two 48-byte integers)
- Security level
- 192 bits
How to decode a JWT token online
Paste your token
Copy a JSON Web Token and paste it into the encoded box. You can also load the example token to try it out.
Read the decoded data
The header and payload are decoded instantly. Switch to the Claims tab for plain-English explanations and expiry status.
Verify the signature
Enter the secret (HMAC) or public key (RSA/ECDSA) to confirm the token is authentic and hasn't been tampered with.