The sibyl attack is a graph theory problem, not a cryptography problem, and its application is in distributed systems. But distributed systems are a cryptography problem, so, if the moderators permit, I would like to ask about this problem here: Yacy is an open source distributed search engine for publishing, but the hard problem is the sibyl attack, the problem that Google refers to a a link farm – a bunch of fake sites that link to each other to give each other fake reputation. Not clear how Yacy addresses the sibyl attack, and I suspect that if usage of Yacy increases, it will be subject to such attacks. Similarly, systems for giving people reputation for supplying goods are subject to sibyl attack with fake customers. Big problem with Dark Web sites that attempt to do an ebay on Tor. Distributed systems tend to be subject to sibyl attacks. Resolving the sibyl attack is a problem of partitioning the graph to see if a group of nodes well connected to each other are, considered as a single node, well connected to rest of the network. ...

How much is search willing to spend on Proof Of Search? Via Proof of * by search nodes, or by Proof of cryptocurrency micropayment for good search result. Or even PKI to various levels of truth? Or is that all the fad talk these days? Of course that involves talk of cryptocurrency, which was first announced yet now banned here, which involves applied cryptographic protocols and networks, which is weird.