Litecoin is one of the first cryptocurrencies built on top of Bitcoin. Litecoin's source was forked from Bitcoin's core code, including the wallet and other sources of Bitcoin. The major change that Litecoin has over Bitcoin is that the PoW algorithm is script instead of Bitcoin's SHA-256. Apart from this, Litecoin has a coin supply limit of 84,000,000 LTC, and the block time is 2.5 minutes.