HS256 vs RS256
HS256 (HMAC-SHA256)
Pros
- Single shared secret — simple setup
- Very fast sign and verify
- Ideal for monoliths and single-service APIs
- Works with browser-based HS256 tools
Cons
- Every verifier needs the signing secret
- Secret distribution is a security risk at scale
- Compromising one verifier exposes the signer
RS256 (RSA-SHA256)
Pros
- Private key signs; public key verifies
- Verifiers never see signing material
- JWKS endpoints for key distribution
- Better for microservices
Cons
- Slower signing (RSA math)
- More complex key management
- Requires infrastructure for key storage and rotation
Verdict
Use HS256 for monoliths and small APIs with a strong 256-bit secret stored in a secrets manager. Use RS256 when multiple services verify tokens, third parties need your public key, or you want signing keys isolated from verifiers. Both are cryptographically sound when implemented correctly — validate the alg header, enforce key length, and rotate keys on schedule. The choice is architectural: symmetric wins on simplicity and speed; asymmetric wins when secret distribution becomes your bottleneck.
Algorithm Guides
Related Tools
Deeper Reading
Frequently Asked Questions
Can I switch from HS256 to RS256 later?
Yes, but it requires reissuing all tokens and updating all verifiers. Plan algorithm choice early.
Which is faster?
HS256 is significantly faster for both signing and verification.