Public key cryptography is a security method used to encrypt and send data. Digital certificates are often used whenever encryption is required on a large scale. The person sending the data uses their certificate to encrypt documents and emails using a public key. When the communication is received by another computer, it is decrypted using a private key.
Web Servers Often Rely Upon Public Key Cryptography for Establishing Trust
Another way in which public key cryptography is used is when computers communicate with web servers. In this situation users are frequently issued a digital certificate containing a public key. The web service verifies authenticity of the users through a certificate authority system. The certificate authority system is responsible for performing the operations to confirm the public keys are valid and trusted. The certificate authority system can even supply public keys between computers after trust is established.