Forgery is the process of making, adapting, or imitating objects, statistics, or documents with the intent to deceive. Use this tag on questions revolving around creating a forgery for a specific encryption scheme or for questions about definitions involving unforgeability.

Forgery is the process of making, adapting, or imitating objects, statistics, or documents with the intent to deceive. For example: in a cryptographic digital signature or MAC system, digital signature forgery is the ability to create a pair consisting of a message $m$ and a signature (or MAC) $\sigma$ that is valid for $m$, where $m$ has not been signed in the past by the legitimate signer.