The Canary Trap: How To Expose A Snitch

In this video you will learn how Tyrion Lannister uses the canary trap to detect a spy, Queen Cercei's spy specifically. He suspects Three people: Grand Meister Pycel, Varys, and Littlefinger; so He decides to test each one separately.

What is the canary trap?: Barium meal test or the canary trap is a method of exposing a leak of information by sharing different versions of a sensitive rumor, secret or document to each of several suspects and noticing which version gets leaked.

These documents often contain a specific wording in order to see if the suspect will repeat them verbatim. So maybe the person devising this trap can use a thesaurus to make each version unique for example.

This can be done in personal or business emails, scopes, or reports. It can be done in normal conversations as we have seen with Tyrion. The key variable in this case was the groom's name.