Public keys are cryptographic keys used in cybersecurity to provide secure communication. It is a form of asymmetric cryptography, meaning that two different keys are used: one for encryption (public key) and one for decryption (private key). The public key is shared publicly and can be used to encrypt messages or data. The private key must remain a secret and is then used to decrypt the encrypted message or data. Public keys help ensure that only the intended recipient can read the message, as only they possess the private key needed to decrypt it. In cyber security, public keys are often used to authenticate users or encrypt communications between parties.