HMAC-SHA256 vs SHA-256

SHA-256 is an unkeyed hash function suitable for deduplication, checksums, and non-adversarial error detection. It does not provide authenticity. HMAC-SHA256 wraps SHA-256 with a secret key to create a message authentication code (MAC) that detects tampering and confirms the sender shares the key.

In security-sensitive systems, prefer HMAC-SHA256 for request signatures, webhook validation, and token integrity. Keep keys random and rotate them periodically. When only collision-resistant fingerprinting is needed (e.g., content addressing), a plain SHA-256 hash is fine.

Related tools

Try: HMAC-SHA256, SHA-256, PBKDF2

FAQ

Can I use SHA-256 alone for integrity?

No. A plain hash provides no authentication; an attacker can recompute it after tampering. Use a keyed MAC such as HMAC-SHA256 for integrity/authentication.

When should I use HMAC-SHA256?

Use HMAC whenever you need to detect active tampering and authenticate the message origin with a shared secret (e.g., API signatures, webhooks, session tokens).