is a cryptographic system that uses two keys -- a public key known to
everyone and a private or secret key known only to the recipient of the
An important element to the public key system is that the public and private
keys are related in such a way that only the public key can be used to
encrypt messages and only the corresponding private key can be used to
decrypt them. Moreover, it is hard to deduce the private key if you know
the public key.
This encryption method is used by SSL to send crucial information between
client and the server like the session key etc.