Ethereum co-founder @VitalikButerin has put concrete probability estimates on one of cryptography's longest-running open questions: when, if ever, will the three most advanced cryptographic primitives become cheap enough for practical, large-scale use?

The 60% Case for Sub-10x Overhead

In a September 6 analysis, Buterin estimated a 60% probability that SNARKs, fully homomorphic encryption (FHE), and indistinguishability obfuscation (iO) will achieve sub-10x overhead when factoring in combined energy consumption and amortized computing costs. Overhead, in this context, refers to the extra computing power, energy, and cost required to perform a computation with cryptographic security applied. A 10x overhead, for instance, means a protected computation consumes roughly ten times the resources of an unprotected one.

To understand the stakes, it helps to know what each technology does. SNARKs (Succinct Non-interactive Arguments of Knowledge) let you prove something is true without revealing the underlying data, and they form the backbone of zero-knowledge proofs, which power everything from Ethereum's Layer 2 rollups to privacy-preserving transactions. FHE allows computation on encrypted data without ever decrypting it. iO, meanwhile, hides a program's internal logic so that two programs doing the same thing appear indistinguishable after obfuscation.

Buterin also gave all three a 33% chance of approaching 1+ε overhead for average real-world computation, meaning encrypted computations could become almost as cheap as running them without any protection at all.

SNARKs Lead the Pack, iO Remains the Hard Problem

Of the three technologies, Buterin sees SNARKs as the most mature, noting that achievable overhead for SNARKs has already reached single digits in specialized scenarios, specifically for dedicated hash functions and certain large language model inference tasks. He expects SNARKs to hit single-digit overhead multiples more broadly by the end of the decade.

iO is a different story. Although recent research has strengthened iO's theoretical foundations, its practical costs remain extremely high, and Buterin has described traditional constructions as effectively "galactic" in computational expense. To reduce those costs, his recent work has explored approaches including diamond iO and local mixing. Diamond iO lowers the theoretical burden but remains impractical, while local mixing takes a different route whose security is still unproven.

Buterin also highlighted the work of Poseidon and STARK researchers, crediting them with meaningful advances in cryptographic efficiency. Cheaper SNARKs could make verifiable computation more routine, while FHE could expand private computation across shared data, and efficient iO could help protect the internal logic of executable software.

For now, Buterin's 60% estimate remains a personal probability assessment rather than an Ethereum roadmap commitment. Even so, the framing of concrete odds by one of the field's most prominent figures signals growing confidence that these technologies are moving from theoretical curiosity toward practical relevance.

Sources:
Blockonomi: Vitalik Buterin Sees 60% Chance SNARKs, FHE, and iO Reach Sub-10x
Crypto Briefing: Vitalik Buterin sees 60% chance SNARKs, FHE, and iO reach sub-10x overhead
GN Crypto News: Buterin, iO Is Cryptography's Hardest Problem