Security Budget Fragmentation in L2s

As Ethereum grows, many Layer 2 (L2) networks are being built on top of it to handle more transactions, lower fees, and scale better. But with this growth comes a quiet problem: security budget fragmentation.

Let’s break it down.

What is a Security Budget?

Every blockchain pays a certain amount (in tokens) to keep its network safe. This is called the security budget. It’s used to pay validators or sequencers who protect the network from attacks.

On Ethereum, this security budget is high because thousands of people are running validators, and they are all rewarded with ETH. This strong security is part of what makes Ethereum trustworthy.

What Happens with L2s?

L2s like Optimism, Arbitrum, and Base are built on top of Ethereum. They don’t have their own validators — instead, they post data to Ethereum, and rely on Ethereum’s security.

That sounds fine, right?

But here’s the issue…

The Fragmentation Problem

Each L2 is a separate environment, with its own sequencer (usually centralized) and fee system. The fees collected by L2s don't directly help Ethereum’s validators — instead, they only pay Ethereum for posting transaction data.

Now imagine we have 50+ L2s, all doing their own thing:

• Each has its own token or economic model
• Each pays Ethereum a little, but not enough to strengthen Ethereum security
• No shared security model across L2s
• Harder to coordinate protection against attacks like MEV, reorgs, or censorship

The result? The security money gets spread out across many small systems — instead of staying concentrated in one big, strong system.

That’s security budget fragmentation.

Why It Matters

This fragmentation creates a few challenges:

1. Weaker Collective Defense – Instead of all L2s contributing to Ethereum’s strength, they split off.
2. More Attack Surfaces – Each L2 may have different rules and levels of decentralization.
3. Less Aligned Incentives – L2s may optimize for their own profit, not Ethereum’s health.
4. Data Availability Risks – If an L2 has poor data posting, users could lose access to funds during issues.

Possible Solutions

Builders and researchers are working on ways to reconnect L2s more tightly with Ethereum’s security:

• Shared Sequencers – Let multiple L2s use the same secure ordering system.
• Restaking and AVSs (Actively Validated Services) – Use Ethereum validators to also secure L2s.
• Rollup Revenue Sharing – Part of L2 fees could go back to Ethereum validators.
• Enshrined Rollups – Future designs where L2s are more deeply baked into Ethereum itself.

Final Thoughts

Security budget fragmentation isn’t a disaster — but it’s a growing issue that needs attention. If Ethereum becomes the settlement layer for 100+ L2s, we need to make sure its security grows with them.

Solving this means better coordination, new designs, and shared infrastructure — so that Ethereum and its L2s stay secure, scalable, and sustainable.

For More Info related to Mitosis please follow official links below

Mitosis Website : https://mitosis.org/

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Mitosis Docs : https://docs.mitosis.org/