Bitcoin Atom (BCA) brings a truly decentralized way of digital asset exchange – with on-chain atomic swaps on board. By using built-in hash time-locked contracts (HTLCs) and its own HTLC API, Bitcoin Atom attempts to disrupt the way we exchange cryptocurrencies today, giving independence from intermediaries and any centralized entities.
Gapcoin is a new prime number based p2p cryptocurrency, which tries to eliminate the sticking points of other scientific currencies like Primecoin or Riecoin. It's a fork of Satoshi Nakamotos Bitcoin, a decentralized payment system which is independent of banks, governments and other centralized regulators. With Gapcoin, you will be able to anonymously send money around the globe in no time. The big improvement in comparison to Bitcoin is that instead of burning electricity for its own sake, Gapcoins Proof of Work function actually does useful work by searching for large prime gaps