a brief history of Ethereum

On July 20, the developers’ idea was implemented on Block 1,920,000 in the form of a controversial Ethereum hard fork, which returned investors’ funds but was not supported by the followers of the idea of decentralization, based on the inadmissibility of such an intervention in blockchain. As a result, the old network chain continued to exist in the form of the Ethereum Classic project with its own development team.

In October 2016, the network was subjected to several DoS-attacks on spamming and empty transactions, which were responded to by two more unscheduled hard forks:

1. EIP-150 (Block 2,463,000 on 18 October) was an urgent technical effort to improve network resilience;
2. Spurious Dragon (November 22 on Block 2,675,000) — consisted of several updates aimed at changing the maximum size and pricing of operating codes, making future possible attacks financially unprofitable for hackers. It also implemented protection against replay attacks and a mechanism to remove blank accounts created by hackers, which helped reduce the size of blockchain and speed up client synchronization.

3. Judging by the fact that Ethereum network was not slowed down anymore due to intentional actions of hackers, Ethereum hard forks were effective.

The next planned phase of development was Metropolis — a set of updates to prepare the network for the transition to the Proof-of-Stake (PoS) mining algorithm and the implementation of solutions for network scaling, which due to the complexity of simultaneous implementation of all planned changes was divided into two separate hard forks.

The Byzantium upgrade was activated on 16 October 2017 at Block 4,370,000 and focused on optimizing gas consumption, improving safety and speed of the network. An important element was the transfer of the almost activated complexity bomb by a year and a half ahead. This is one of the reasons why hard fork was carried out on that date — further growth in the complexity of the network would have led to the termination of mining and the onset of the “ice age”, to which the Ethereum was not yet ready.

Support for verification of RSA signatures, several new operating codes and cryptographic models, as well as the use of smart contracts in confidential transactions using zk-SNARKs tools were also added. In addition, Byzantium has implemented a parallel transaction chain processing mechanism that should help develop future blockchain scalability and significant acceleration solutions.

The second update of the Metropolis phase was initially expected to be implemented on November 2018. However, after an attempt to launch Constantinople hard fork in the test network, the project team faced a number of critical bugs that disrupted the network.

It was then announced that the Ethereum hard fork will be held on January 17th at Block 7,080,000. But just a day before the activation, Constantinople was cancelled again. The reason for this was the discovery of a vulnerability in one of the included updates (EIP 1283) that could have been exploited by the attackers to carry out a “re-entry attack” and steal users’ funds.

There was no time to fix the problem update because of the urgent need to migrate the bombs again, which did not start to work in time. Therefore, EIP 1283 was simply decided to remove from the planned network upgrade assigned to block 7 280,000, which was supposed to be found in the last days of February.

Constantinople was activated on the night of February 28 to March 1. Together with it, the updating of St.Petersburg which has removed from a bad network EIP has been started. Activation of this update led to another delay of the “complexity bomb” (by about 12 months), a reduction in the miner award (from 3 ETH to 2 ETH) and the time of extraction of the block to a record 13 seconds (before that was 20–21 seconds).

In addition, the gas requirements for some types of transactions were reduced, the efficiency and speed of the Ethereum virtual machine were improved, and the smart contract code was optimized and the ease of development was improved.

The activation of Constantinople has prepared the Ethereum network for the last of the planned stages of the complex updates under the general name of Serenity. Its implementation should lead to the transition to Casper PoS protocol and the cancellation of the current mining model.

Also, developers work on sharding, a technology that will help scale Ethereum by implementing a mechanism for processing transactions by multiple parallel blockchains connected to a common network. When both solutions are implemented, this will a new era of Ethereum 2.0, an energy-efficient blockchain platform capable of handling thousands of transactions per second.

According to the latest data, the Ethereum Roadmap now includes the launch of Beacon Chain (the Casper protocol management solution) in early 2020, the implementation of the remaining components of Serenity in the fall of the same year, and yet unnamed Ethereum hard fork in 2019, which will reduce coin emissions by a factor of 10 in March 2021.