Viacoin is an open source crypto-currency created in 2014, derived from the Bitcoin protocol that supports embedded consensus with an extended OP_RETURN of 120 bytes. Viacoin has a total supply of 23 million coins and a 24 second block time, which means a transaction speed 25x faster than Bitcoin. Other features include a mining difficulty adjustment algorithm called DarkGravityWave, Scrypt Auxpow and Versionbits to allow for 29 simultaneous Soft Fork changes to be implemented at a time.
Viacoin has adopted SegWit. Segregated Witness helps to shrink the size of a transaction and cope with the UTXO growth. It also aims to increase the per-block transaction throughput by a factor of 2 or 3, while simultaneously making block syncing faster for new nodes. Viacoin will also integrate other features like Schnorr signatures, which will help to lower the transaction size and costs.
With Viacoin you can perform cross-chain atomic swaps between different cryptocurrencies without using centralized exchanges. Viacoin was the first altcoin to integrate Peter Todd's OP_CHECKLOCKTIMEVERIFY BIP 65 proposal. Our atomic swap contract uses SHA256 secret hashes (instead of RIPEMD160) as it is more secure and has wider compatibility with altcoins.