How many keys are required for public key encryption?

Public key encryption, also known as asymmetric encryption, requires two keys to function effectively. One key is the public key, which can be shared openly and is used to encrypt data. The other key is the private key, which is kept secret and is used to decrypt the data that has been encrypted with the matching public key. This dual-key mechanism ensures that even if someone obtains the public key, they cannot decrypt the information without access to the corresponding private key, thereby providing a layer of security. The requirement of two keys distinguishes public key encryption from symmetric encryption, which uses a single key for both encryption and decryption.