What is a STARK?

A STARK is a zero-knowledge proof built from hash functions alone. It needs no trusted setup and no elliptic curves, so it is expected to hold up against quantum computers.

Also called zk-STARK or scalable transparent argument of knowledge.

How a STARK works

  • The computation is written down as a table of steps.
  • Each column is stretched into a polynomial, so any mistake in the table shows up almost everywhere.
  • Everything is sealed in a Merkle tree of hashes.
  • The verifier checks a few random spots against the tree, and blinding makes those spots reveal nothing about the inputs.

STARKs and SNARKs

SNARKs such as Groth16 have very small proofs, need a trusted setup and rest on elliptic curves. STARKs have larger proofs, need no setup and rest on the hash, which is what the T for transparent stands for.

In Redacted

In bunker mode, every spend from your private balance is proved with a STARK whose only cryptographic building block is SHA-256, with no trusted setup.

Bunker mode →

Related terms

Zero-knowledge proofA zero-knowledge proof lets someone prove that a statement is true without revealing anything else, for example that they own funds and may spend them, without showing which funds or who they are.zk-SNARKA zk-SNARK is a zero-knowledge proof that is small, quick to verify and needs only one message from the prover, which is why blockchains can check them inside a smart contract.Trusted setup ceremonyA trusted setup ceremony creates the public parameters that some zero-knowledge proof systems need. Each participant adds secret randomness and destroys it, and the result is safe as long as at least one participant was honest.Hash functionA hash function turns any input into a short fingerprint of fixed size. The same input always gives the same fingerprint, and nobody can work back from it or find two inputs that share one.Merkle treeA Merkle tree fingerprints a long list with one short value, the root, so that anyone can prove an item is in the list with a handful of hashes instead of the whole list.

Sources: Scalable, transparent, and post-quantum secure computational integrity, Ben-Sasson et al., 2018

Updated October 12, 2026. All terms