Abstract: A public key cryptosystem with roaming user capability within a network that allows secure communication between users of the system, client machines, and encryption servers. A client machine generates and stores an encrypted private key on an encryption server. A user may then access the encrypted private key from any client machine located on the network and decrypt it using a passphrase, thus giving the user roaming capability. The private key may then be used to decrypt any encrypted messages received. A user can generate a digital message, encrypt it with a client recipient's public key, and transmit it to the encryption server from any client machine on the network.