Log Periodic

Log Periodic is an independent research and development lab working on protocols to improve the internet's resilience and efficiency.

Range-Based Set Reconciliation is a method for synchronising data-sets. This article describes the theory behind RBSR and introduces Log Periodic's negentropy project.

negentropy is a protocol specification for a method of set reconcilliation. This allows two parties to compare remote databases and determine which entries are missing on each side, using only a logarithmic number of bandwidth and network round-trips. Reference implementations in C++ and Javascript are included, along with analysis and tests.
strfry is a C++ implementation of the nostr protocol, a distributed communication protocol that approximates CRDTs. strfry is designed to be highly efficient, and supports syncing of data-sets using the negentropy protocol.
quadrable is an authenticated multi-version database. It is implemented as a sparse binary merkle tree with compact partial-tree proofs. There are C++ and Solidity libraries, as well as a git-like command-line tool.
ephemerand: A globally-consistent randomness beacon that extracts unpredictable data from the GPS almanac.