Method and apparatus for encrypted communication in data networks

In a data communications network having a plurality of nodes interconnected for communicating messages through the network, the method of performing secure message communication, comprising the steps of

• at a message originating node,
• determining the identity of a destination node to receive a message,
• selecting an encryption key from one or more alternative keys, said selected key being shared with another node along a route toward the destination node,
• encrypting the message with the selected key,
• forming a communication by, including with the encrypted message a clear identification of the originating node and an clear identification of the decrypting node with which the selected key is shared, and
• transmitting the communication toward the node with which the selected key is shared.

In a data communications network having a plurality of nodes interconnected in a selected manner for communicating messages through the network, the method of performing secure message communication, comprising the steps of

• at a message originating node,
• determining the identity of a destination node to receive a message,
• determining if the originating node shares a first encryption key with the destination node, and, if so, encrypting the message with the first key,
• otherwise, selecting a second encryption key shared with any other node along the message route to the destination node and encrypting the message with the second key,
• forming a communication by including with the encrypted message a clear identification of the decrypting node with which the selected key is shared by the originating node and a clear identification of the originating node,
• transmitting the communication along a route which includes the node with which the selected key is shared.

A method for secure communication performed at a node of a communication network, comprising the steps of

• generating an encrypted version of a message to be transmitted to a destination node by
• selecting an encryption key from one or more alternative keys, said selected key being shared with another node along a route toward the destination node,
• encrypting the message with the selected key,
• forming a communication by including with the encrypted message a clear identification of the encrypting node and an clear identification of the decrypting node with which the selected key is shared, and
• transmitting the communication toward the node with which the selected key is shared.

Apparatus in a data communications network having a plurality of nodes interconnected for communicating messages through the network, comprising

• means for determining a route from an originating node to a destination node,
• means for encrypting a message intended for the destination node with one or more alternative keys known to other nodes in the route,
• means at each node in the route for determining if a received message is encrypted with a key known to the receiving node,
• means responsive to the last determining means for decrypting the message,
• means for re-encrypting the decrypted message with a different key shared with any other selected node in the remaining route, and
• means for transmitting the re-encrypted message on the remaining route.

Apparatus at each node of a data communications network having a plurality of nodes interconnected for communicating messages through the network, comprising

• means for determining a route from an originating node to a destination node,
• means for selecting as a message decrypting node any other node along the route with which the originating node shares an encryption key,
• means for encrypting a message with the selected key,
• means for adding the identities of the originating and decrypting nodes in clear form to the encrypted message,
• means for transmitting the message along the route,
• means for decrypting a received message,
• means for determining if the node is not the destination node for the received message, and
• means responsive to the last determining means for re-encrypting the decrypted received message with a key shared with any other selected node in the remaining route, and
• means for transmitting the re-encrypted message on the remaining route.