Base released a decentralization plan that would focus on introducing fraud proofs and diverse client software to make the chain censorship-resistant.

To match the censorship resistance of layer-1 chains like Ethereum, layer-2 rollups need to minimize centralized points of control. However, achieving full decentralization from the start is extremely complex.

When Base Protocol launched in 2022 on Optimism, it still relied on "training wheels" of temporary centralization:

• A centralized sequencer to efficiently order transactions.
• Contract upgrades controlled by the Base team and Optimism.
• Transaction finality determined by the two teams' agreement.

This allowed Base to launch quickly with strong reliability and security guarantees. But it fell short of the permissionless ideals cryptocurrency aspires to.

To progress decentralization, Base needed to transfer control from teams to community-run protocols. The 2-2 and 1-2 structures were key mechanisms designed to enable this transition.

Hence, Base Protocol is launching a key management structure design to remove any single point of centralization. 

Optimism has faced some criticism over its lack of active fraud proofs; I believe the Base team is taking the right approach by constructively working to improve the protocol.  

This includes a 2-2 contract upgrade multisig and 1-2 challenger key structure.  

The 2-2 contract upgrade multisig has two parts:  

• Base Upgrade Multisig: Managed by the Base team
• Optimism Foundation Multisig: Managed by the Optimism Foundation

Both keys are required to execute smart contract upgrades on Base. This prevents either entity from unilaterally controlling upgrades. Upgrades will be determined through Optimism governance, with Base and Optimism Mainnet sharing upgrades to remain compatible.

The 1-2 challenger key structure is for deleting invalid withdrawal proposals from L2 to L1 to prevent double-spending. It consists of a key:

• controlled by Base
• controlled by Optimism Foundation

This structure ensures neither party alone can control the challenger functionality.  

The 2-2 contract upgrade multisig and 1-2 challenger key structure are important for decentralizing control over critical parts of the Base Protocol for a few key reasons:

• Prevents central points of failure - With decentralized keys, there is no single entity that can cause failures or outages through their control.
• Enhances censorship resistance - No single entity can unilaterally decide to censor transactions or users.
• Sets precedent - As a major L2, Base's structure can influence other protocols to also adopt decentralized controls.
• Allows community oversight - Governance through Optimism can provide community input on upgrades and challenges.

Here is a hypothetical example:

The Base team wants to upgrade the Base Protocol smart contracts to add a new feature. To do this upgrade, they need approval from the 2-2 multisig:  

• The Base team signs approval with their Base Upgrade Multisig key.
• This approval is sent to the Optimism Foundation to sign with their Optimism Foundation Multisig key.
• Both signatures are required to execute the smart contract upgrade.

2-2 Contract Upgrade Multisig

To decentralize governance of smart contract changes, Base implemented a 2-2 multisig structure for upgrades:

• 2 signers are required - Base team and Optimism Collective.
• Both must agree to any contract changes or additions.
• Neither party can unilaterally control upgrades.

This was an improvement over sole control by either Base or Optimism over the codebase. Requiring joint approval aligned incentives and prevented unilateral actions.

But it still relied on centralized teams rather than community control. So Base designed it as an interim step before transitioning contract governance fully on-chain.

Now let's say a hacker tries to submit an invalid withdrawal proposal from L2 to L1. This could allow double spending of funds.   To delete this invalid proposal, approval is needed from the 1-2 challenger key structure:  

• The Base team tries to delete the proposal with their challenger key.
• This deletion transaction is sent to the Optimism Foundation to co-sign with their challenger key.
• Both challenger signatures are required to delete the invalid withdrawal.

1-2 Challenger Keys

Similarly, the finality of transactions required centralized oversight:

• Invalid transactions could be finalized without recourse.
• Censorship of valid txs was also possible without fraud proof.

Base introduced a 1-2 challenger key structure to mitigate this:

• If Base or Optimism find an invalid tx, they can jointly issue fraud proof.
• This prevents unilateral control over transaction finality.
• Challenges follow an on-chain governance process.

Like the multisig, the goal is ultimately fully on-chain fraud proofs and consensus. However, the 1-2 model enhanced protections and aligned incentives in the interim.

Decentralized approval is required in both instances. This further prevents central points of failure of the protocol.  

Thoughts

It's true that without fraud proofs fully implemented, Optimism's sequencer could theoretically settle invalid transactions. However, I see the Base team's contributions as a tremendously positive sign.

Rather than just criticizing, Base is collaborating closely with Optimism developers to actively implement solutions. They are driving major improvements to enable fraud proofs and further decentralize the network.

Initiatives like diverse client implementations, Pessimism monitoring tools, and decentralized governance structures will measurably improve security and censorship resistance. And Base isn't just stopping at Optimism - they are spearheading the development of an entire Superchain ecosystem of scalable L2s.

This is how real progress happens in Web3 - through open-source collaboration and a focus on building, not just critiquing. I'm confident these contributions will lead to a more mature, trusted Optimism and vibrant L2 ecosystem.

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