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.
Populous is a peer-to-peer invoice platform founded in 2017 at a high point in the blockchain and cryptocurrency craze. It makes use of blockchain's distributed ledger technology to provide a global trading platform for invoice financing. According to the Populous website, 'invoice finance is a form of funding that instantly unlocks the cash tied up in outstanding sales invoices. Business owners allow invoice buyers to buy invoices at a discounted rate in order to unlock their cash quicker. Once invoices are paid by the invoice debtor, the invoice buyer receives the amount previously agreed upon.' In order to offer funds to invoice sellers, Populous maintains a Liquidity Pool. This is tied in with the Populous cryptocurrency (PPT). An investor securitizes PPT by making an initial purchase. PPT is then held in escrow as collateral throughout the process. Transactions between invoice buyers and sellers take place with Pokens, exchanged for PPT and used as the currency for buying and selling invoices, either drawing from or contributing to the Liquidity Pool in the process. As a result of this built-in liquidity component, Populous at this point requires no transaction fees. In fact, the only fees levied are those associated with late payments. Populous invoice transactions can cover a huge array of industries, including many which are not typically available to traditional financing companies. The PPT tokens not released during the ICO were retained by the founding and development team. PPT can either be held or used as collateral to invest in Populous invoices. In exchange for collateralizing, you’re given an amount of Pokens based on a percentage of market value. Currently it’s the lesser of 50%, or a 30 day market average. These are automatically used to purchase an invoice. If the invoice is repaid, you receive both your PPT investment and Pokens profit.