The collective name for cryptocurrencies offered as alternatives to Bitcoin. A clone of the Bitcoin protocol, with some modifications. (See Cryptocurrency ) Bitcoin is the first widely accepted cryptocoin experiment. Others have followed the Bitcoin protocol to develop new cryptocurrency variations, including Litecoin, Primecoin and Ripple, for example. The modifications are intended to improve or refine the Bitcoin protocol. Litecoin has a quicker transaction confirm time, scrypt as proof-of-work and higher number of coins. Primecoin finds prime numbers at the same time it confirms its blocks. Namecoin has a special key-value storage. In theory, an altcoin can be started from an existing Bitcoin blockchain, although no known example exists at this writing. (See also Fork .) At this writing, only Bitcoin has the critical mass to make it a likely success as a cryptocurrency and store of value. The alt-coins are experiments in attributes that could perhaps be adopted by Bitcoin to improve its characteristics and attributes. Alternative cryptocurrencies using the SHA-256 hashing algorithm can be mined using the same hardware used to mine Bitcoin such as FPGA and ASIC devices. Scrypt based alt-coins, such as Litecoin, Novacoin and Feathercoin, can be mined using GPU cards.
Malone, J.A (2015). Glossary of Bitcoin Terms and Definitions. United States: Lulu Press, Inc