An adventurer found a chest with treasures in a cave guarded by a pirate. He had 3 keys that were golden, silver and black. But only one of them could open the chest. The pirate would give the adventurer only one chance to reach the treasure.
If he chose the right key, he would take the chest. If he was wrong, the pirate would kill him right there. The only clue was this cipher: TGK HOE ELY DEN.
Which is the right key?