Ethereum Byzantium hard fork: So far so good, so what?

10/16/2017 - 16:09 UTC
Ethereum Byzantium hard fork: So far so good, so what?

The Ethereum network completed the planned hard fork, Byzantium, at block number 4,370,000 at 05.22 UTC. What changes did Byzantium bring to Ethereum?

Byzantium, the fifth hard fork on Ethereum network so far, is a change to the protocol with new rules which improve the system.

For instance, the fork brought increased block mining speed (estimated to be ~14.1 sec in the end) which means lower transaction times for Ethereum users.  Before Byzantium, the block generation speed was ~30 secs. Thus the decrease will be almost 50%. It remains to be seen, how much this can affect the actual transaction verification times.

Byzantium also decreased the reward to miners, which was 5 Eth per block before the hard fork. The mining reward from is now 3 Eth per mined block, meaning a 40% revenue decrease for miners.

At the time of writing this article, the block times were well below the 20s, while the difficulty has fallen almost 50% from 3,000T to 1,634T.

All Ethereum clients needed to upgrade, otherwise, they would be stuck on an incompatible chain following the old rules. At the time of writing, mining on the old chain has ceased. The developers celebrated as everything went smoothly.

The fork of the second largest cryptocurrency by market cap also means that there is now a 'hard' EOL limit for mining GPUs with 3GB . These GPUs will stop mining Eth next year.

The following upgrades were included in Byzantium:

  • Addition of ‘REVERT’ opcode, which permits error handling without consuming all gas (EIP 140)
  • Transaction receipts now include a status field to indicate success or failure EIP 658)
  • Elliptic curve addition and scalar multiplication on alt_bn128 (EIP 196) and pairing checks (EIP 197), permitting ZK-Snarks and other cryptographic mathemagic™
  • Support for big integer modular exponentiation (EIP 198), enabling RSA signature verification and other cryptographic applications
  • Support for variable length return values (EIP 211)
  • Addition of the ‘STATICCALL’ opcode, permitting non-state-changing calls to other contracts (EIP 214)
  • Changes to the difficulty adjustment formula to take uncles into account (EIP 100)
  • Delay of the ice age / difficulty bomb by 1 year, and reduction of block reward from 5 to 3 ether (EIP 649)