Keeping the Sei Network safe from quantum computers
TL;DR: Sei Labs has shared a new proposal, SIP-5, that lays out how existing accounts can stay safe once quantum computers are powerful enough to break today’s cryptography. The plan lets users keep current addresses and balances, allowing you to add a quantum-resistant key when you are ready, and does it all well before any real threat exists.
What is SIP-5
Every EVM blockchain today rests on the same kind of cryptography. It works because the math behind it is impossible for classical computers to reverse. A powerful enough quantum computer would change that. In theory, it could take a public key that has already been seen onchain and work backward to the private key that controls the account.
That machine does not exist yet, but many experts believe the timeline for one is accelerating. The point of SIP-5 is to introduce a solution well before a threat exists.
SIP-5 is Sei Lab’s proposed path for upgrading existing accounts to quantum-resistant security without breaking anything people already rely on. It is a proposal, shared openly, so the ecosystem can look at it and decide together how to move forward.
Why this is the right time to talk about it
Quantum computers capable of breaking today’s signatures are not here. Waiting until the threat is imminent, however, means designing the fix under pressure. Rushing such an upgrade could introduce many implementation risks.
SIP-5 takes the opposite stance. It proposes adding the quantum-resistant option far in advance, so the solution is in place well before the threat exists. And, if the timeline moves faster than anyone expects, the network is already prepared.
What it would mean for account holders on Sei
Your address will stay the same. Your balance will stay the same, as will your transaction history, approvals, and the contracts you interact with. SIP-5 is built specifically to avoid forcing users to abandon their old accounts.
Under SIP-5, when you are ready, you attach a new quantum-resistant key to your existing account. From that point on, the account would be protected by the new key. Under the proposal, you would also choose your own pace. You can move early if you want the extra security sooner, or you can wait.
The real trade-offs
This approach has two trade-offs, which is why Sei Labs is not proposing it as something to immediately be implemented.
The first is that there is a future cutoff point, set by governance if and when the plan is adopted, after which an account can only continue to send transactions if it has already added its quantum-resistant key.
An account that never adds one would still be able to receive funds, but it would no longer be able to send. That is the practical reason the option is being introduced so far ahead of time. The window to prepare is meant to be long and unhurried, which is only possible if the conversation starts now.
The second trade-off is that upgrading to post-quantum signatures will slow the performance of every EVM blockchain. Today’s post-quantum signature schemes are many times larger than existing signature schemes. That means bigger messages to broadcast across the network, so fewer can be sent at once.
To solve for these tradeoffs Sei Labs is simultaneously proposing the emergency solution that SIP-5 provides, and beginning work on finding an even better solution through new, high-performance post-quantum cryptography.
Where this fits
SIP-5 is a proposal and it is written that way on purpose. It defines the minimum needed to keep accounts working across a quantum transition and leaves the bigger governance decisions for the moment they actually become relevant. Wallets, explorers, and other tooling would need time to add support, and the proposal calls for that groundwork to be in place before any cutoff is ever set.
A network built for modern trading has to plan for long term threats that are not immediate today. SIP-5 is what that looks like in practice.
Read the full proposal here: https://github.com/sei-protocol/sips/blob/main/sips/sip-5.md