Litecoin (LTC) is an altcoin based on the Bitcoin model.
Litecoin uses scrypt in its proof-of-work algorithm — more complex cryptographic sequential memory-hard function.
The Litecoin Network aims to process a block every 2.5 minutes, which its developers claim allows for faster transaction confirmation. Amongst other advantages of faster processing is the greater resistance to a double spending attack over the same period (as compared to Bitcoin).
The Litecoin Network will produce 84 million Litecoins, or four times as many currency units as will be issued by the Bitcoin Network.