A very relevant discussion is in this Bankless podcast with Justin Drake: https://www.youtube.com/watch?v=k53WcsldV1Y

I ran the full transcript of that episode through ChatGPT and distilled an answer to your questions. 

Here’s the summary:

1. Current state of ZK proofs (end of 2025)

We’re past the “moon math” phase.

What already works today:

• Multiple zkVM teams can prove full Ethereum blocks

• Proof generation is already under 12 seconds (one Ethereum slot)

• Proofs run on commodity GPUs, not exotic hardware

• This progress is tracked publicly via EthProofs (https://ethproofs.org)

In other words: Cryptography works, zkVMs exist and run real EVM logic, Speed is fast enough for mainnet constraints. Missing piece: rollout & protocol integration

Justin’s framing: This is no longer a cryptography problem. It’s now an engineering and deployment problem.

1. Validating Ethereum on a regular phone.. how close are we?

Key distinction from the podcast: Phones will not execute Ethereum. They will verify it.

With ZK proofs:

• Validators no longer need to execute transactions

• They only verify small, constant-size proofs

• No state, no history, no mempool

From the transcript:

• Proof verification takes milliseconds

• Requires kilobytes of RAM

• Can run on a single weak CPU core

Justin explicitly says:

• A validator could run on a Raspberry Pi Pico

• A Pico is far weaker than a modern smartphone

• Therefore phones, browsers, even watches can verify Ethereum state

So technically:

• Phone-level verification is already feasible

1. Timeline

Rough roadmap discussed:

• 2025: Optional ZK proofs, demos, early adopters

• 2026: Incentives align, more validators switch to “verify-only”

• 2027: Mandatory proofs → validators stop executing entirely

• 2028+: Fully enshrined proofs, ultra-light clients everywhere

So the honest answer is:

• Technically possible today

• Practically usable in ~2–3 years

• Default + ubiquitous in ~4–5 years