CryptoKitties is a blockchain based game in which users collect and trade digitally scarce virtual cats using ETH tokens. Each kitty has a unique 256-bit genome which defines it's appearance and traits. Players are able to breed new kitties who inherit traits from their parents' genome. AxiomZen developed the game including the five smart contracts which allow users to interact with the Ethereum blockchain. The blockchain tracking of the CryptoKitties means that the kitties are permanently and immutably available on the blockchain regardless of the original creators continued support of the project. CryptoKitties is a new type of digital asset known as a cryptocollectables, other examples include CryptoPets, CryptoPuppies.
Supply and breeding
The supply of kitties is limited based a fixed number of new kitties called Gen 0 kitties released every fifteen minutes. Additionally, users can choose a mother and father to breed a genetically unique offspring. The rate at which users can breed new kitties is limited, and users also have to pay a fee to breed.
Each kitty has a unique genome represented by a 1 or a 0 at each position of their 256-bit genome. The exact genome of the kitty is stored on the blockchain represented by this string of bits. This genome determines the properties of the kitty such as background color, breeding cooldown time, whiskers, beard, and others. Players can sire a new offspring from a chosen set of parents. This is done by a genetic algorithm which mixes the genetic data from the parents as well as info from the ethereum block hash to create a unique offspring. The offspring may have unique or desirable properties to players which make them more desirable for trading on the Cryptokitties marketplace.
A cracking program was developed which allows users to determine the exact genes of the offspring for a given 256 block time segment. If the user doesn't like that specific gene set they could wait 256 blocks and get another iteration based on the block hash and so on until they arrived at a desired gene set.
Buying and selling of cryptokitties occurs on a marketplace using the digital wallet called MetaMask.
By December 3, 2017 more than $1 million dollars worth had been transacted through the game and was the most popular decentralized application on the Ethereum network, responsible for 15% of all traffic. The network congestion caused by the game highlighted the blockchain scalability issues for the Ethereum network and blockchains in general.
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Documentaries, videos and podcasts
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The Future of CryptoKitties
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- BlockchainA blockchain is an append-only digital ledger storing a set of time-ordered transactions grouped in blocks that are linked together using cryptographic hashes.
- Decentralized application (dApp)A decentralized application (dApp) is a service that provides direct interaction between providers and end users providers through a blockchain or distributed ledger.
- CryptocurrencyA cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange using cryptography to secure the transactions and to control the creation of additional units of the currency. Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies.
- EthereumEthereum is an open-source, public, distributed blockchain computing platform featuring smart contract (scripting) functionality, which facilitates online contractual agreements.
- MetamaskMetaMask is a browser extension that acts as a bridge between internet browsers, Ethereum, and decentralized applications built on the Ethereum network.
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