Who's that traitor at the door?

Here's an interesting etymological tidbit I stumbled across today.
You've heard of "Lost in the translation," what about when meaning is "gained in the translation?"
My peephole "door viewer" is "The portal of Judas." At first I thought it was Spanish, but it is actually French, and in French "judas" means both "spyhole" and "traitor." I love this stuff.