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.
Zcash is a decentralized and open-source cryptocurrency that offers privacy and selective transparency of transactions. Zcash payments are published on a public blockchain, but the sender, recipient, and amount of a transaction remain private. Zcash is based on peer-reviewed cryptographic research, and built by a security-specialized engineering team on an open source platform based on Bitcoin Core's battle-tested codebase. Our improvement over Bitcoin is the addition of privacy. Zcash uses advanced cryptographic techniques, namely zero-knowledge proofs, to guarantee the validity of transactions without revealing additional information about them. How Zcash works Zcash encrypts the contents of shielded transactions. Since the payment information is encrypted, the protocol uses a novel cryptographic method to verify their validity. Zcash uses a zero-knowledge proof construction called a zk-SNARK, developed by our team of experienced cryptographers based on recent breakthroughs in cryptography. These constructions allow the network to maintain a secure ledger of balances without disclosing the parties or amounts involved. Instead of publicly demonstrating spend-authority and transaction values, the transaction metadata is encrypted and zk-SNARKs are used to prove that nobody is cheating or stealing. Zcash also enables users to send public payments which work similarly to Bitcoin. With the support for both shielded and transparent addresses, users can choose to send Zcash privately or publicly. Zcash payments sent from a shielded address to a transparent address reveal the received balance, while payments from a transparent address to a shielded address protect the receiving value. Check out CoinBureau for guide on What is ZCash.