When Worlds Collide 
When the crypto developer OP Labs rolled out software a year ago making it easy for companies to spin up their own distributed networks atop the Ethereum blockchain, the option quickly became so popular that it attracted the likes of the big U.S. crypto exchange Coinbase, which used the platform to build its new blockchain, Base.
But in recent months, technical experts have homed in on a crucial deficiency of the setup: that networks based on the OP Labs software were missing an element known as “fault proofs” that are theoretically at the very core of their operations.
OP Labs officials have repeatedly said that getting fault proofs into operation was a top priority – so much so that the project even had its own name, “Cannon.” The lack of the security feature has been likened to driving a fast car without airbags.
On Tuesday, OP Labs took its first step toward addressing the concerns, launching fault proofs on a test network known as OP Goerli Testnet.
Fault proofs, sometimes known as fraud proofs, are at the core of optimistic rollup technology, a system for connecting layer-2 blockchains or “rollups” to primary layer-1 blockchains like Ethereum; the tech is used to “prove” that certain data from the rollup can or cannot be trusted.
But projects that rely on the technology are still in varying states of adolescence. Arbitrum, another optimistic rollup, currently relies on roughly a dozen designated validators to handle fraud proofs, but is pushing to broaden that out so that it’s a “permissionless” system.
Optimism, a layer-2 blockchain atop Ethereum that served as the template for OP Stack’s software, previously had released fault proofs on its main network, but removed them due to security concerns, Karl Floersch, the CEO of OP Labs, told CoinDesk in an interview.
“Essentially, what we did was we ended up building a first pass, realizing that it was not the sustainable path forward, went to the drawing board, re-envisioning the way that this system works, and then, fast forward a year and a half, and we’re actually seeing the the kind of fruits of those design decisions,” Floersch added.
Some blockchain experts have argued that rollup technology without fault proofs is a security risk, as transactions are unsafe or can be spoofed with.
The deployment of fault proofs on the test network, or “testnet,” is the first step toward implementing it on the OP Stack. OP Labs says the software should also eventually be able to accommodate so-called “zero-knowledge” proofs, relying on a promising cryptographic technology that could be used as an alternative to fault proofs.
Martin Köppelmann, a long-time Ethereum developer and co-founder of the Gnosis blockchain, tweeted in August when Coinbase’s Base went live that until fault proofs are added, “all the ~$3b that are in the Optimism and Base bridges can be taken out any time, and users can do nothing about it.”
Floersch said he’s aware of the criticism but told CoinDesk that he believed that in order to ship fault proofs, blockchain projects first needed to address governance and decentralization.
To reach that stage, known as stage 2 decentralization, Floersch shared that in February, OP Labs mapped out the network’s architecture to decentralize certain elements of the protocol.
“Until there is stage two decentralization, the fault proof is not something that is the primary source of security on your chain,” Floersch told CoinDesk. “If governance can override the fault proof, then the fault proof is useful, but it is not the thing that you’re relying on for your primary source of security.”
Read more: Ethereum’s Layer 2 Rollups Reduce Costs, but the Risks Are Underappreciated
Pro Tip: Don’t Fear the Lull. Fear Missing the Exit 
