Overview
The Sphinx cryptographic packet format is a compact and provably secure design introduced by George Danezis and Ian Goldberg. It supports a full set of security features: indistinguishable replies, hiding the path length and relay position, detection of tagging attacks and replay attacks, as well as providing unlinkability for each leg of the packet’s journey over the network.
Sphinx is used in lnd to relay anonymized messages within the Lightning Network.
Resources
References
[1] https://github.com/lightningnetwork/lightning-rfc/wiki/Rendez-vous-mechanism-on-top-of-Sphinx
[2] https://katzenpost.mixnetworks.org/docs/specs/sphinx.html