EVM - RareSkills

Storage Slots in Solidity: Storage Allocation and Low-level assembly storage operations This article examines the storage architecture of the Ethereum Smart Contracts. It explains how variables are kept in the EVM storage and how to read and write to storage slots using low-level assembly (Yul). This information is a prerequisite to understanding how proxies in […]

The second preimage attack for Merkle Trees in Solidity The second preimage attack in Merkle trees can happen when an intermediate node in a merkle tree is presented as a leaf. The name of this attack is quite misleading because it implies hashes have a second preimage. Modern hash functions do not have multiple (computable) […]

Ethereum precompiled contracts Ethereum precompiles behave like smart contracts built into the Ethereum protocol. The nine precompiles live in addresses 0x01 to 0x09. The utility of precompiles falls into four categories – Elliptic curve digital signature recovery – Hash methods to interact with bitcoin and zcash – Memory copying – Methods to enable elliptic curve […]

EIP-2930 – Ethereum access list Introduction An Ethereum access list transaction enables saving gas on cross-contract calls by declaring in advance which contract and storage slots will be accessed. Up to 100 gas can be saved per accessed storage slot. The motivation for introducing this EIP was to mitigate breaking changes in EIP 2929, which […]

EIP-150 and the 63/64 Rule for Gas Introduction EIP-150, or Ethereum Improvement Proposal 150, is a protocol upgrade for the Ethereum blockchain. It was proposed on March 18, 2016, and implemented on July 20, 2016, as part of the Ethereum Byzantium hard fork. There were several changes in the protocol, but we will focus on […]

Convert gas to USD (Ethereum) Understanding gas cost can be tricky because there are three components at play: the gas price, the price of ether, and the units of gas. The “gas price” that you might see on a website like etherscan.io/gastracker, which fluctuates with network demand. The price of Ether. Obviously, the more expensive […]

What makes blockchain immutable? Note: This article is intended to be understandable by non-technical readers, to gain a very technical understanding, refer to our blockchain bootcamp after reading this article. Contrary to popular belief, blockchains are not immutable because of cryptography, but because of economic incentive. Cryptography is just a nice tool that makes the […]

Ethereum smart contract creation code 608060405260405160893803806089833981016040819052601e916025565b600055603d565b600060208284031215603657600080fd5b5051919050565b603f80604a6000396000f3fe6080604052600080fdfea26469706673582212204a131c1478e0e7bb29267fd8f6d38a660b40a25888982bd6618b720d4498b6b464736f6c634300080700330000000000000000000000000000000000000000000000000000000000000001 This article explains what happens at the bytecode level when an Ethereum smart contract is constructed and how the constructor arguments are interpreted. Table of contents We discuss the following topics with visual examples: Introduction Init code Payable constructor contract Non-payable constructor contract Runtime code Runtime code breakdown Constructor […]

Solidity Gasleft Introduction The purpose of this article is to describe the behavior of the solidity gasleft() function and its uses. It is a built-in function that is used to check the remaining gas during a contract call. It is one of the special variables and functions that always exist in the global namespace and […]

Generate Ethereum Address from Private Key Python Generate Ethereum Address from Public Key An Ethereum address is the last 20 bytes of the keccack256 of the public key. The public key algorithm is secp256k1, the same used in bitcoin. Because it is an elliptic curve algorithm, the public key is an (x, y) pair corresponds […]

Smart contract creation cost Smart contract creation cost can be anywhere from $10 to \$2,000 assuming Ether costs between $1,500 to \$2,000. The biggest factors are 1) Ethereum price, 2) the size of the compiled contract (in bytes), 3) the current gas price on the Ethereum network. There are a total of six components that […]

Solidity RSA signatures for aidrops and presales: Beating ECDSA and Merkle Trees in Gas Efficiency Updated: Aug 4, 2023 By Suthan Somadeva and Michael Burke ECDSA Vs RSA Introduction Creating a contract that gives certain addresses permissions goes by several names: airdrops, presale, whitelist, allowlist, and so forth. But the essence of the idea is […]