In 2009, Satoshi Nakamoto introduced Bitcoin to the world, the first widely adopted cryptocurrency operating on blockchain technology. Despite the revolutionary concept, Bitcoin's functionality was initially limited to serving as electronic cash.
However, the potential of blockchain extends far beyond digital currencies. Many crypto enthusiasts recognized this, attempting to enhance Bitcoin's functionality through additional protocols and services. The limited scripting language of Bitcoin restrained the development of full-fledged decentralized applications.
In 2013, programmer Vitalik Buterin published the concept of Ethereum—a platform designed to enable the creation of virtually any decentralized application on top of the blockchain. Ethereum utilizes a universal language of smart contracts that operate within the Ethereum Virtual Machine environment.
Unlike Bitcoin, Ethereum allows not only the transfer of values between addresses but also the execution of arbitrary contract code that modifies the blockchain's state. This opens up vast opportunities for creating decentralized versions of social networks, messengers, exchanges, games, and many other services.
Contracts in Ethereum are stored at specific addresses and contain code in a language similar to JavaScript. Contracts may include state variables, functions for reading/writing state, and logic for sending transactions. Transactions can be initiated by both external accounts and other contracts.
Miners in Ethereum generate blocks, including transactions from the pool and executing smart contracts. Proof of Work (PoW) is used for consensus. The cryptocurrency of Ethereum—Ether—serves as internal fuel for paying for network computational resources.
In addition to "smart contracts," Ethereum aims to provide broad capabilities for building token systems, financial derivatives instruments, reputation systems, and many other services that are difficult or impossible to implement in Bitcoin due to script limitations.
In the fall of 2014, the Ethereum public testnet was launched. In the summer of 2015, a pre-sale of Ether was held for enthusiasts and developers. And in July 2015, the Ethereum mainnet was launched.
Over the years, Ethereum has become the dominant platform for ICOs, token launches, and decentralized software development. Although initially focused on smart contracts, the majority of activity in the Ethereum ecosystem at present revolves around financial applications.
One of the key challenges of Ethereum, limiting its mass adoption, is scalability. Like Bitcoin, Ethereum utilizes a model where each node processes every transaction. This severely restricts the number of transactions per second and leads to significant resource costs for storing the blockchain.
Ethereum developers are working on addressing scalability issues. One proposed solution is transitioning to a sharding model, dividing the blockchain into independent segments—shards—for parallel transaction processing. Other approaches include using "light" clients that store only a portion of the data and various "coupon" schemes to reduce storage costs.
In addition to scalability, Ethereum engineers are also working on improving defense against attacks, implementing a more efficient proof-of-stake consensus algorithm, and adding privacy features. Despite current limitations, interest in the platform remains high.
Thanks to Ethereum's versatility, it is already being used in hundreds of projects, and its ecosystem remains the most active in the cryptocurrency world. As existing issues are addressed, Ethereum has the potential to become the foundation of a new decentralized economy and propel the development of crypto technologies forward.
https://courses.cs.duke.edu/spring23/compsci512/papers/ethereum.pdf