Bitcoin is the first digital currency based on blockchain. It solved the double-spending problem and enabled peer-to-peer transactions on a large scale. Bitcoin was designed to work as a trustless digital currency that would function without government oversight or a central bank.
Bitcoin was developed by Satoshi Nakamoto, whose identity has never been confirmed and has become the subject of great intrigue. Bitcoin builds upon on other cryptographic and digital currency projects that came before it, but its use of blockchain made it more viable. Nakamoto originally released his white paper and open-source software on a cryptography forum. He mined the first block of the Bitcoin chain, called the genesis block in January 2009.
Bitcoins are created as a reward for a process known as mining. One of the core innovations of Bitcoin, is its consensus algorithm, which creates an incentive system that rewards miners for confirming transactions.
Hal Finney, who developed the first reusable proof-of-work system (RPOW), several years before, was the first Bitcoin adopter and received the first bitcoin transaction ever recorded on its blockchain.

PascalCoin is the first blockchain that can be deleted, and reduces the dependency of the entire blockchain history to verify transactions. It is a Proof-of-Work (PoW) cryptocurrency that places a strong emphasis on achieving the same level of scalability as credit card networks such as VISA. Pascal's architecture is based on an innovative cryptographic structure called the SafeBox. It facilitates faster transactions by storing account balances separately from the blockchain. The SafeBox only uses the last 100 blocks on the chain to update transaction history. This allows the network nodes to synchronize much faster while preserving the security of the blockchain, and reducing the computing resources needed to maintain it.
PascalCoin also enables simplified account naming to make it easier to transfer funds.

Eternal is a Japanese cryptocurrency project that consists of Eternal Coin (XEC) and Eternal Token (XET). The project appears to be primarily focused on remittance payments, but can also be used as a medium of exchange for other purposes. XEC holders receive weekly dividend payments, and can only be traded through the company's authorized exchanges. XET was created to allow users to trade XEC on other crypto exchanges. 1 XET=10 XEC.