鍵 - key

key

keyboard (of a piano, typewriter, etc.)

public key cryptosystem

private key (cryptography); secret key

section of road that is curved on purpose as a defensive measure

locksmith

key success factor; key to success; KSF

melodica; keyboard harmonica; Pianica

symmetric key cryptography

symmetric key cryptography

secret key cryptography; symmetric key cryptography

private account (on social media, esp. Twitter); account that can only be viewed by approved followers