1. ANNOY library. https://github.com/spotify/annoy
2. Benchmarking for fast searching of nearest neighbors. https://github.com/erikbern/ann-benchmarks
3. Code signing. https://en.wikipedia.org/wiki/Code_signing. Accessed 25 Aug 2023
4. Email authentication. https://en.wikipedia.org/wiki/Email_authentication. Accessed 25 Aug 2023
5. Fast nearest neighbour search and scalable clustering