Ethereum Abandons Poseidon: What Changes for ETH

Ethereum has abandoned Poseidon after 8 years of research and is moving to SHA or BLAKE. This decision affects developers, validators, and ETH holders.

Ethereum Foundation researcher Justin Drake announced the change on August 13, 2026. He called it the result of 8 years of work and a step toward post-quantum security.

Why did Ethereum abandon Poseidon?

Poseidon was long considered a convenient hash for SNARK systems. Such schemes are needed when a network must quickly verify computations without revealing unnecessary data.

But new research changed the picture. Drake says SHA2 and BLAKE2s can deliver similar efficiency in SNARKs when working through binary fields. In simple terms, standard algorithms turned out not to be as slow as they once seemed.

There is another important point. Ethereum Research now considers SHA and BLAKE3 more mature from a cryptanalysis standpoint. That means fewer surprises in the future.

In June 2026, the Ethereum Foundation team had already described a separate design for a post-quantum registry of validators' public keys. So abandoning Poseidon does not look like a sharp turn. It is part of a longer plan.

What does this decision mean for network security?

The main reason is simple: quantum computers. Ethereum's current signatures, ECDSA for user accounts and BLS for validators, could become vulnerable in the future.

That is why the team is moving toward post-quantum schemes. The official Ethereum PQ roadmap already includes separate I*, J*, L*, and M* forks. It covers a key registry, precompiles for PQ signatures, leanVM, and PQ-safe blobs.

The numbers here are telling. Ethereum.org estimates hash-based signatures at roughly 3,000 bytes versus 96 bytes for BLS. LeanVM is expected to deliver about 250× compression through SNARK aggregation. For a large network, that is no small matter.

As of August 14, 2026, Beaconscan showed 898,225 active validators and 1,133 pending. At that scale, any cryptographic change requires very careful implementation. Otherwise, a mistake could be costly.

Market reaction

The market is currently treating this as a technical update rather than an immediate price trigger. But for long-term ETH holders, it is an important signal: the team is not waiting until the problem becomes critical.

"In retrospect, the key was not SNARK-incompatible hashes, but a SNARK that supports hash functions," Justin Drake wrote.

This fits well with Ethereum's broader direction. Vitalik Buterin has long spoken about simplifying the network's base layer. His idea of gradually replacing the EVM with RISC-V sounds logical here: less unnecessary complexity, more suitability for proofs.

Google Quantum AI research adds another layer. In 2026, it estimated breaking ECDLP-256 in two scenarios: fewer than 1,200 logical qubits and 90 million Toffoli gates, or fewer than 1,450 logical qubits and 70 million Toffoli gates. For Ethereum, that is a direct signal not to delay the transition.

• The Ethereum Foundation is abandoning Poseidon for L1.

• SHA or BLAKE are being considered instead.

• The decision is tied to post-quantum security.

• Drake says the research took 8 years.

• The leanVM production version is planned for 2027.

• Consensus-layer and execution-layer changes are expected in 2028.

What does this mean for investors?

For traders, this news is not about a quick pump. What matters more is whether delays appear in the roadmap. If the team keeps pace, that supports confidence in ETH as the base asset of a large network.

For long-term holders, the meaning is different. Ethereum is showing that it is thinking not only about today's fees, but also about security several years from now. This is a rare case where a complex technical change directly affects the investment quality of the asset.

There is also a practical takeaway for Ukrainian users. If the network really moves toward simpler and more proven algorithms, that could reduce risks in the operation of wallets, validators, and services that store ETH. When large sums are involved, extra complexity helps no one.

The current timeline also matters. EF sees the leanVM production version in 2027, and consensus-layer, data availability, and execution changes in 2028. It is a long road, but it is already broken down into stages.

Frequently asked questions

Why is Ethereum abandoning Poseidon?

Because new research showed that SHA2, BLAKE2s, and BLAKE3 can be sufficiently efficient in SNARK systems. At the same time, they appear more mature from a cryptanalysis perspective. For the network, that means less technological risk.

When does Ethereum plan new changes?

According to the roadmap, the leanVM production version is expected in 2027. Consensus-layer, data availability, and execution changes are scheduled for 2028. Separate PQ forks have already been split into stages I*, J*, L*, and M*.

Does this affect ordinary ETH holders?

Yes, but not immediately. The changes concern the network's base security, and therefore trust in ETH. For users, this matters through wallets, signatures, and future compatibility with post-quantum schemes.

Ethereum is once again shifting the focus to security rather than trendy solutions. And that looks rational. For those following the market and wanting to quickly sell Ethereum ETH on Monobank, it is convenient to have a simple route at hand without extra steps.

This material is not financial advice. Cryptocurrency trading involves significant risks. Part of this text was prepared with the help of artificial intelligence based on public sources and reviewed by our editorial team.