Grin coin is a private & lightweight open source project based on the mimblewimble blockchain implementation. MimbleWimble is a lightweight blockchain protocol proposed by anonymous author that goes by the name Tom Elvis Jedusor (inspired by Harry Potter) in July 2016. Since then, the proposal has gained a huge following among Bitcoin and privacy advocates. Unlike bitcoin or ethereum, there are no addresses in Grin. In order to transact using Grin, both wallets must communicate with each other online with the results broadcasted to the network. Another key different is that transaction history (sender, receiver, amount) will not be recorded on the blockchain. Due to the removal of these information from the transaction, the data size remains small and that keeps the blockchain lightweight. New nodes can easily join the network without having to download a large blockchain. Grin coin was launched without an ICO, fundraising, or pre-mine. Developers around the world contribute openly with the goal to ensure the coin distribution remains as fair as possible. There are 2 popular wallets widely available to interact with the Grin network. Grin core wallet: https://www.coingecko.com/buzz/how-to-use-grin-wallet-to-send-receive-grin-coins Wallet713: https://www.coingecko.com/buzz/how-to-use-grin-wallet713-to-send-and-receive-grin-coin-step-by-step-guide The consensus algorithm used by Grin is the Cuckoo Cycle proof-of-work based. There are 2 hashing algorithms involved with Grin. Cuckoo-29 is meant for GPU mining while Cuckoo-31 is meant fo ASIC mining. This is a deliberate design to encourage miners to eventually move into ASIC mining for efficiency while keeping it fair at the beginning of the launch. Grin coin has launched its mainnet on 15th January 2019 and is now available for mining and trading.
Launched on Dec 25, 2016, Obyte is a distributed ledger based on directed acyclic graph (DAG). Thanks to absence of blocks and miners, access to Obyte ledger is decentralized, disintermediated, free (as in freedom), equal, and open. Obyte is the first DAG based cryptocurrency platform to support dApps. Due to absence of miners and blocks, there is no risk of front-running and other miner manipulation, and dApps are safer and easier to develop than blockchain based dApps. DApps are developed in Oscript - a new language that avoids many unsafe programming patterns common in earlier dApp platforms. Thanks to its safety, Obyte is especially well suited for DeFi apps, some are already available on the platform, such as Discount Stablecoins (https://ostable.org), some are being developed. Other features include: self-sovereign identity, private untraceable currencies, sending crypto to email using textcoins, and extremely small-footprint libraries suitable for small IoT devices.