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.

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. strfry is designed to be highly efficient, and supports syncing of data-sets using the negentropy protocol.

Ephemerand: A globally-consistent randomness beacon that extracts unpredictable data from from the GPS almanac.

Defido2: Contract-based ethereum wallet that repurposes commonly available FIDO2 two-factor login devices for cryptocurrency operations.