Nonce
In plain terms
A one-time random value used to prevent replay attacks.
Going deeper
A nonce ('number used once') is included in requests or crypto operations to ensure each is unique, blocking attackers from reusing captured messages. It guarantees freshness.
Under the hood
Used in authentication, CSP, and cryptography; reuse defeats its purpose.
Examples
Replay prevention, CSP nonces, crypto protocols, OAuth, signed requests.
Think of it like...
Like a single-use confirmation code that won't work a second time.