1. A Quick Intro to the EVM’s Storage Structure
Let’s start with a visualization of the EVM’s storage structure. When you create a smart contract, it gets stored on the Ethereum blockchain (or another EVM compatible chain). This storage is similar to a vast array of bytes, where each slot of this array can store 32 bytes.
Each of these slots is addressable and labeled with hexadecimal values, which is a base-16 numbering system that uses 16 distinct symbols: the numbers 0 to 9 (for values 0–9) and the letters A to F (for values 10–15).
Considering that storage slots on the EVM are addressed in 32-byte increments, the first slot starts at 0x00, the next at 0x20, and so on. Each one of these slots holds 32 bytes of data. For instance:
-
the 28th byte at the first slot would be accessible at the address
0x1b; -
the 6th byte at the second slot would be accessible at the address
0x25.