Private keys are very important for cryptocurrency users. If a device fails, or gets stolen, with the private key a wallet can be restored on a new device. Private keys are needed to claim new coins in case of a fork.
The blockchains need all transactions to be recorded on the blockchain. Raiden network, similar to lightning network, uses payment channels to make payments off-chain, It's very interesting to see how it works.
Pirl is the first Ethash based Masternode Crypto, inspired by the Ethereum project. Pirl is ASIC resistant, built on an entirely new chain, and harnesses the power of Smart Contracts. Learn how to mine it.