When assembled, the key would unlock the locked-off room behind the guardian.

It took Feri a few moments to get the keys to unlock the gates.

There's a hatch underneath, the key to the airlock door unlocks it.

The captain produced a big, brass key, unlocked the huge door, and swung it open with difficulty.

There is no door, no opening, which any key might unlock.

When a message has been locked with a public key, only the private key can unlock it.

In each level, the player must either kill all enemies or use keys to unlock enough doors to get to the exit.

The key would unlock a chest that contains four sandbags.

The key is identifying and unlocking the values which provide the best return on investment in ways that can be measured by utilities.

The second key on the ring unlocked it.