Bitcoin is the very first crypto currency created in the framework of blocking technology. It is based on the SHA-256 algorithm. The total number of coins is limited to 21 000 000 units. Works with the Proof of Work protocol. The production of crypto currency is carried out by means of so-called "mining" using powerful equipment (ASIC or a farm from video cards). Bitcoin is offered at all without exception crypto-exchange exchanges and is in high demand not only from the crypto-currency community, but also from investors who earn on the difference in quotations. At the time of this writing, bitcoin is distinguished by high commissions for transactions and an increase in the time spent for them in connection with the growing interest in the asset. Update Lightning is designed to solve this problem.