Cryptonote

      CryptoNote is an application layer protocol, developed by the little known Nicolas van Saberhagen,that aims to solve specific problems identified in Bitcoin, namely:

   – Traceability of transactions
   – The proof-of-work function
   – Irregular emission
   – Hardcoded constants
   – Bulky scripts

The Cryptonote protocol powers several decentralized privacy-oriented cryptocurrencies such as Bytecoin, Boolberry, Dashcoin, DigitalNote, Monero, AEON, etc (more implementations found here).