(cryptography) secret key

(cryptography) public key

(cryptography) key exchange - an exchange of peers' keys at initialization phase of connection.

(idiomatic) to hold the key (to)

(Internet slang) protected account (on social media, especially Twitter and Instagram)

to lock (a door, etc.) / (Internet slang) (of a SNS account) to change privacy setting to limited people and posts and/or profiles can be seen by limited people.

black key (of a piano, etc.)

white key (of a piano, etc.)

(colloquial) current boyfriend

everything