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Layered Encryption


Classification Key : Exterior Security, Information Disclosure

Problem

In the mix protocol, the mix nodes share symmetric keys between themselves. The mix decrypts and then re-encrypts the packets flowing through the node. This protects against a passive adversary observing the network traffic, but is insufficient against an active adversary controlling a mix node. A malicious attacker controlling the mix node can follow the mix protocol, and yet profile the behavior of a message sender, because of the header in plaintext available to him. How can the mix network be made secure against an active adversary?

Solution

The sending client is responsible for establishing the path between the sender and the recipient. The neighboring nodes in the circuit share symmetric keys between themselves. The packet is then encrypted in multiple layers (like the onion skin). The innermost layer is encrypted with the symmetric key used in the last hop before the server, the next layer is encrypted with the symmetric key used in the preceding hop and so on.

Known Uses

Layered encryption (also known as onion routing) in Morphmix.

Related Patterns

Morphed Representation

Source

Hafiz Privacy Patterns

Tags

Anonymity, Privacy, Encryption, Routing


 

Last modified: May 05, 2012

Conceived and Maintained by: Munawar Hafiz