Ethereum Considers Migration to Poseidon Hash Function Ahead of Pectra Upgrade

Ethereum is exploring the potential migration to the Poseidon hash function ahead of its Pectra upgrade, a decision that could significantly improve Ethereum’s zero-knowledge (zk) proof capabilities. In a recent post on X, Vitalik Buterin, co-founder of Ethereum, invited researchers to join the Poseidon cryptographic analysis program, aiming to gather more insights into the security of Poseidon as Ethereum considers adopting it.

The primary goal behind this exploration is to enhance the network’s integration with zk-provers (tools that verify transactions privately) and zero-knowledge rollups (a method used for scaling). The Poseidon hash function, first introduced in 2019, is seen as a better fit for zero-knowledge proofs compared to older, well-established hash functions like SHA-256 and Keccak, which were not specifically designed for zk-proof systems. While SHA-256 and Keccak have undergone extensive testing and are widely used, they aren’t optimized for zk-technology, whereas Poseidon was created specifically for use in zero-knowledge applications. Despite being newer, Poseidon has already found application in production, especially in Layer-2 systems on Ethereum and other blockchain projects.

In November 2022, the Ethereum Improvement Proposal (EIP) 5988 was introduced. This proposal suggested adding a precompiled contract to the Ethereum Virtual Machine (EVM), which would implement the Poseidon hash function. The aim was to improve interoperability between the EVM and zk-rollups, thereby making Ethereum more scalable and efficient when handling zk-proof transactions. However, since the introduction of EIP 5988, there hasn’t been any major update or official implementation of this proposal. Still, it appears that Ethereum is seriously considering Poseidon for future use.

Ethereum’s potential move to Poseidon is part of a broader series of upgrades designed to enhance network performance. The most notable of these upgrades is the Pectra upgrade, which is scheduled for launch on April 8, 2025. The Pectra upgrade is expected to bring several significant improvements, such as enhanced scalability, better account abstraction, increased layer-2 efficiency, and higher validator rewards. This follows the Dencun hard fork set for March 2024, which is anticipated to significantly reduce transaction fees on Layer-2 networks, further enhancing Ethereum’s scalability and reducing costs for users.

Ethereum’s exploration of Poseidon is an important step toward continuing to evolve and optimize its network, making it more efficient and better suited for the needs of developers and users in the ever-growing decentralized finance (DeFi) and blockchain ecosystem.