OpenSK is an open-source implementation for security keys written in Rust that supports both FIDO U2F and FIDO2 standards.

The full and complete NTP Reference Implementation from the Network Time Protocol Project at Network Time Foundation.

ASIC/FPGA miner in c for bitcoin

Command-line JSON processor

Bitcoin Core integration/staging tree

Skein/Threefish/Fortuna implementations for ZRTP4J used by Jitsi