Cryptocurrency

Cryptocurrency
Cryptography for confidential payments began to be used since 1990 in the DigiCash system of David Chaum, whose company went bankrupt in 1998. This payment system was centralized.

For the first time, the term "cryptocurrency" began to be used after the appearance of the payment system "Bitcoin", which was developed in 2009 by a person or a group of people under the pseudonym Satoshi Nakamoto (the identity has not yet been established). The term "cryptocurrency" became widespread after the publication of Andy Greenberg's article entitled "Crypto Currency" in Forbes on April 20, 2011.
Later forks appeared: Namecoin (decentralized DNS for registration within the .bit domain zone), Litecoin (uses scrypt hashing), PPCoin (uses a hybrid proof-of-work/proof-of-stake mechanism, does not have an upper limit on the emission volume), Novacoin (similar to PPCoin, but uses scrypt) and many others.

Until July 2013, the software of all cryptocurrencies, except Ripple, was based on the open source code of the Bitcoin system. In July 2013, other platforms began to appear, into which various infrastructure was integrated - exchange services, stores, messengers, etc. Such crypto-platforms include: Bitshares, Mastercoin, Nxt and others.
Altcoins are all cryptocurrencies that appeared after Bitcoin.
The first altcoins appeared in 2011: Litecoin and Namecoin. Their developers sought to overcome a number of problems inherent in bitcoin (for example, Litecoin has a higher transaction speed) or use blockchain technology in other areas (Namecoin was developed to build alternative root DNS servers).
Many altcoins are essentially very similar to bitcoin, have similar characteristics, and the same equipment as bitcoin can be used to work with them, but some cryptocurrencies have significant differences. Ethereum has turned into a crypto platform due to the use of "smart contracts". Even stronger independence from Bitcoin is visible in Ripple, which is actually a centralized system. A number of cryptocurrencies, such as Dash, have focused on increasing anonymity.
Sometimes a new cryptocurrency appears as a branch (fork) from another cryptocurrency due to changes in parameters that make the data of the old and new systems incompatible. This usually happens when some participants switch to a new protocol, and some stick to the old one. At the same time, both cryptocurrencies can have a common transaction history - which accumulated before the moment of their separation.