Both STARKs and SNARKs are cryptographic proof systems that can be used to attest to computational correctness, and we discuss them (and other systems) in detail in this blog post and this webinar. Briefly, there are a few important distinctions between the two:
Larger Proofs: While STARK proofs are larger than SNARK proofs, the important metric to compare when considering a scaling solution is the amortized gas cost per transaction. STARKs offer a greater ability to scale, with amortized values as low as 600 gas/tx in production systems operating in Rollup mode (on-chain data).
SHARP, StarkEx’ SHARed Prover, allows several disparate dApps to send their batches of transactions to be validated in one proof, further reducing the amortized gas cost per transaction.
Safer Cryptographic Assumptions: STARKs are provably secure and rely on well tested theoretic principles. STARKs assume only the existence of a cryptographic hash function, which is a well-explored and time-tested assumption (the web and e-commerce rely on it). STARKs are also post-quantum secure.
The security of SNARK constructions requires additional theoretic assumptions – many of them new and untested, such as “knowledge of exponent” assumptions. Quantum computers will be able to break these assumptions, and the underlying security under classical (non-quantum) attacks is still a matter of ongoing research.
A Universal L1 Verifier: Thanks to Cairo, a Turing-complete language for scaling dApps using STARKs, a single Cairo Verifier smart contract on L1 can verify the STARK proof for any computational statement. This allows new applications to benefit from the track record of the Cairo Verifier deployed on Mainnet and serving dYdX, Immutable X, deversiFi, Sorare, and others.
No Trusted Setup: Many SNARK constructions require a trusted setup. Moreover, the size of the setup key grows linearly with the size of the computation being performed. Larger computations require larger (and new) setup keys or other mitigations (such as recursion). Finally, generating a trusted setup for SNARKs in a safe manner is a complex process that should be tightly monitored – as it impacts the integrity of the financial system to be built on top of it.
STARKs are Transparent, i.e. they require no trusted setup whatsoever – making their use simpler and safer.