HMAC: Use the shared secret key. RSA/ECDSA: Use the public key in PEM format (include the -----BEGIN PUBLIC KEY----- header).
Decoded Content
Header
Payload
Note: RSA and ECDSA encoding requires private keys and is not supported in the browser environment for security reasons. Use the HMAC algorithms for encoding, or use a server-side library for RSA/ECDSA.
Encoded JWT
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