StoneStarkware

Description

Stone is a STARKShort for "scalable transparent argument of knowledge", a STARK is a type of zero-knowledge proof that resolves one of the primary weaknesses of ZK-SNARKs, its reliance on a "trusted setup”. STARKs also come with much simpler cryptographic assumptions, avoiding the need for elliptic curves, pairings, and the knowledge-of-exponent assumption and instead relying purely on hashes and information theory. This means that they are secure even against attackers with quantum computers. proof systemThe infrastructure that allows projects to verify their state transitions. It is composed by onchain verifiers and offchain provers. The main two flavors are optimistic and ZK proof systems, but they can be combined in a hybrid model. In general though, if a system is able to accept state roots optimistically, even if it has a ZK component, it is considered an optimistic proof system. that is designed to prove the execution of programs written in Cairo language and compiled into Cairo assembly (cASM) byte code. This ISAInstruction Set Architecture of a virutal machine describes its computational model, including the available instructions, registers, data types, etc. is highly optimized for the performance of zkVMA special type of zk proving system that proves the correctness of state transitions of a virtual machine. Computation is represented by a program in a specific instruction language, it can have private and public inputs and public outputs. Most of zkVMs are STARKs. proving. Stone verifies STARK proofs directly onchain without any final SNARKShort for "succinct non-interactive argument of knowledge", a SNARK is a widely used type of zero-knowledge proof that is short and fast to verify. Different kinds of SNARKs are usually systematized by proof size, verification time, and type of setup. The most famous SNARKs are Groth16, PLONK/Marlin, Bulletproofs, and STARKs. wraps and thus requires no trusted setupGeneration of a piece of data that must then be used for some cryptographic protocol to run. Generating this data requires some secret information. The "trust" comes from the fact the secret must be destroyed after the ceremony, otherwise cryptographic properties of the protocol could be broken. Once the data is generated, and the secrets are forgotten, no further participation from the creators of the ceremony is required. There are two types of trusted setups for SNARKs: (i) trusted setup per circuit where it is generated from scratch for each circuit, (ii) trusted universal setup per proving system where it can be used for several circuits.. Stone targets 80 bits of security (e.g. see constructor params on this contract).

Proof system

Stone is a Cairo-based zkVM with AIRAlgebraic intermediate representation (AIR) is a type of arithmetization commonly used in zkVMs. It represents a trace of zkVM state transitions with low degree polynomial constraints that enforce the correct relation between previous and current states of the computation. Several variations of AIR are used in practice, with slight differences among them. arithmetizationA part of zk proving system, a process that transforms the computation to be proven into a set of polynomials with particular properties. over felt252 field and FRIA proximity test method that is used to determine whether a set of points is mostly on a polynomial with a degree less than a specified value. It resembles the FFT but the arithmetic complexity of its prover is strictly linear and that of the verifier is strictly logarithmic.-based commitment. The protocol makes use of recursive proof aggregation among many projects utilizing the CairoVM (i.e. Starknet forks and StarkEx systems) using SHARP. Some documentation on the aggregation scheme can be found here and the Cairo verifierAn entity in a ZK-Rollup, often a smart contract, that verifies zero-knowledge proofs submitted by a prover. implemented in Cairo can be found here.

StarkNet Operating System (SNOS)

The base layer of Stone proving is a Cairo program called SNOS that proves the correct STF from one state to another given the list of transactions. SNOS execution includes checking transaction inputs (e.g. state), executing transactions and processing state diffs. The source code of the Starknet OS can be found here.

Recursive aggregation

Proofs of SNOS executions of several consecutive blocksAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over. are recursively aggregated. The correctness of this aggregation is checked by applicative bootloader program, which also verifies the correct relation of corresponding SNOS inputs and outputs. Applicative bootloader proofs are aggregated across several blockchains and proven by SHARP. The SHARP STARK proof is verified onchain without any SNARK wraps.