Patent ID: 8635441

Claim:
A computer-implemented method for protecting a private computer network, comprising: providing a private protected computer network; receiving at a gateway between a public network and the private protected computer network, data transmitted from a source address outside the private protected network over the public network, for delivery to a destination on the private protected computer network; encrypting the data at the gateway using an encryption key, selected in a pseudo random process, when the data is received, from a set of one or more keys that are not available to the source address; transmitting the encrypted data over the private computer network toward the destination; receiving the transmitted encrypted data, and decrypting the data for use at the destination by means of a corresponding decryption key; and conveying the corresponding decryption key to the destination over the private computer network together with at least a portion of the encrypted data, wherein conveying the decryption key comprises transmitting the decryption key in the clear to the destination, together with at least a portion of the encrypted data.