PKI, or Public-Key-Infrastructure uses asymmetric encryption. There is a public key, and a private key, anything encrypted with a key can only be decrypted with the opposing key.
Public-key cryptography, or asymmetric cryptography, is any cryptographic system that uses pairs of keys: public keys which may be disseminated widely, and private keys which are known only to the owner. This accomplishes two functions: authentication, where the public key verifies that a holder of the paired private key sent the message, and encryption, where only the paired private key holder can decrypt the message encrypted with the public key.
In a public key encryption system, …