Signing and Verifying JWTs
Learn the cryptographic principles behind JWT signing and how to verify a token's integrity and authenticity.
What is JWT Signing?
JSON Web Tokens (JWTs) are powerful, but how do we trust them? Signing is the answer! It's a cryptographic process that ensures a token hasn't been tampered with and comes from a trusted source.
- Integrity: Confirms the token's content hasn't been changed since it was issued.
- Authenticity: Verifies the token was issued by the expected sender.
Without a signature, anyone could create or alter a JWT!
Keys to Security: The Secret
For symmetric signing algorithms like HMAC (e.g., HS256), a single secret key is used. This key is known only to the issuer and the intended verifier(s).
- The secret key is a string of bytes, crucial for both signing and verifying.
- It must be kept highly confidential.
- If the secret key is compromised, your JWTs are no longer secure!
All lessons in this course
- Understanding JSON Web Tokens
- JWT Structure and Claims
- Signing and Verifying JWTs
- JWT Expiration and Validation Rules