Ethereum co-founder Vitalik Buterin wants the crypto industry to grow up fast — stressing that the industry is at an “inflection point.”

Speaking in front of a packed room at the Ethereum Community Conference, in Cannes, France, Buterin used his keynote to deliver a clear-eyed reality check: Decentralization, he argued, must evolve from a catchphrase to a concrete set of user guarantees — or risk becoming another hollow promise.

As the industry has gone mainstream with endorsements from major corporations and political figures, builders need to return to the ecosystem’s key ideals surrounding decentralization and building for users’ needs, Buterin said.

In his typical jeans and relaxed dark T-shirt uniform, Buterin laid out practical “tests” that he said every crypto project should pass. These include 1) the walk-away test. If the company behind an application disappears, do users keep their assets? And 2) the insider attack test: How much damage can rogue insiders or compromised front-ends cause? And 3) whether it has a trusted computing base: How many lines of code must be trusted to protect users’ funds or data?

He warned that too many layer-2 networks, DeFi projects and “decentralized” front-ends rely on hidden backdoors, instant upgrade buttons or insecure interfaces that can be tampered with and hacked.

Even identity and privacy solutions came under his critical eye. Zero-knowledge proofs, he noted, can backfire if users still reveal their entire transaction history when they sign in with centralized providers. Privacy, he added, must flip from being treated as an optional feature to something that reduces data leaks by default.

It will be 10 years this month since the Ethereum blockchain went live, and Buterin has come under pressure over the past few months from the community to address core protocol issues. If not, the blockchain could lose its edge to competitors.

For Buterin, this next phase in Ethereum’s history means building systems that pass the walk-away test, shrink the trusted base of code and resist insider attacks. This includes balancing engineering with simple, robust solutions.

“If we lose that,” he concluded, “Ethereum inevitably just becomes a generational thing, and it inevitably passes like a lot of other things have passed before.”

Read more: Vitalik Buterin Proposes Replacing Ethereum’s EVM With RISC-V