Elliptic curve arithmetic SECP256k1 [L1 ]
Bitcoin/public point to address [L2 ]
A coin-control frontend for bitcoind, and a Tcl-library of lowlevel btc stuff. by Andreas Leitgeb (e.g. Secp256k1, priv/pub/adr conversions, asm&disasm for raw-tx, and a blockchain-parser) [L3 ] [L4 ]