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A zero-knowledge proof is a cryptographic protocol by which a prover convinces a verifier that a statement is true — for example, that a state transition is valid — without revealing any information beyond the truth of the statement itself, satisfying the properties of completeness, soundness, and zero-knowledge. In Solana's ecosystem, ZKPs are used by ZK Compression (via Groth16 SNARKs) to prove correct state transitions for compressed accounts without storing full account state on-chain, and by the Token-2022 Confidential Transfers extension (via ElGamal encryption and range proofs) to prove token balances are non-negative without revealing the actual amounts. Solana's BPF VM exposes the alt_bn128 elliptic curve syscall to make on-chain Groth16 proof verification computationally feasible within the 1.4M compute unit budget.

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Zero-Knowledge Proofs (ZKP) (zk-proofs)
Category: ZK Compression
Definition: A zero-knowledge proof is a cryptographic protocol by which a prover convinces a verifier that a statement is true — for example, that a state transition is valid — without revealing any information beyond the truth of the statement itself, satisfying the properties of completeness, soundness, and zero-knowledge. In Solana's ecosystem, ZKPs are used by ZK Compression (via Groth16 SNARKs) to prove correct state transitions for compressed accounts without storing full account state on-chain, and by the Token-2022 Confidential Transfers extension (via ElGamal encryption and range proofs) to prove token balances are non-negative without revealing the actual amounts. Solana's BPF VM exposes the alt_bn128 elliptic curve syscall to make on-chain Groth16 proof verification computationally feasible within the 1.4M compute unit budget.
Aliases: ZKP, ZK Proofs
Related: Groth16, PLONK

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Groth16

Groth16 is a highly efficient zk-SNARK proving system introduced by Jens Groth in 2016 that produces constant-size proofs (128 bytes: two G1 points and one G2 point on a pairing-friendly elliptic curve) with constant-time verification regardless of circuit complexity, making it the preferred proof system for on-chain verification where calldata and compute costs are constrained. Light Protocol uses Groth16 proofs over the BN254 curve (known as alt_bn128 in Ethereum tooling) to verify compressed account state transitions on Solana, leveraging the native alt_bn128 pairing and point-addition syscalls added to the SVM to keep verification within the per-transaction compute unit limit. The trade-off is that Groth16 requires a trusted setup ceremony per circuit, producing a structured reference string (SRS) whose security relies on participants honestly discarding their toxic waste.

SNARK (Succinct Non-interactive Argument of Knowledge)

Open term

Branch

PLONK

PLONK (Permutations over Lagrange-bases for Oecumenical Noninteractive arguments of Knowledge) is a universal zk-SNARK proving system that requires only a single, circuit-agnostic trusted setup (a universal SRS), eliminating the need for per-circuit ceremonies required by systems like Groth16, while producing proofs that are slightly larger but allow circuits to be updated or added without new ceremonies. PLONK-based systems (including its variants Turbo-PLONK and Ultra-PLONK used by protocols like Aztec) support custom gates and lookup tables, enabling more efficient encoding of operations like range checks and hash functions in arithmetic circuits. On Solana, PLONK is less commonly deployed for on-chain verification than Groth16 because verification is more compute-intensive, but it is used off-chain in toolchains and protocol designs targeting future SVM upgrades with broader syscall support.

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ZK Compression

Groth16

Groth16 is a highly efficient zk-SNARK proving system introduced by Jens Groth in 2016 that produces constant-size proofs (128 bytes: two G1 points and one G2 point on a pairing-friendly elliptic curve) with constant-time verification regardless of circuit complexity, making it the preferred proof system for on-chain verification where calldata and compute costs are constrained. Light Protocol uses Groth16 proofs over the BN254 curve (known as alt_bn128 in Ethereum tooling) to verify compressed account state transitions on Solana, leveraging the native alt_bn128 pairing and point-addition syscalls added to the SVM to keep verification within the per-transaction compute unit limit. The trade-off is that Groth16 requires a trusted setup ceremony per circuit, producing a structured reference string (SRS) whose security relies on participants honestly discarding their toxic waste.

Open term

ZK Compression

PLONK

PLONK (Permutations over Lagrange-bases for Oecumenical Noninteractive arguments of Knowledge) is a universal zk-SNARK proving system that requires only a single, circuit-agnostic trusted setup (a universal SRS), eliminating the need for per-circuit ceremonies required by systems like Groth16, while producing proofs that are slightly larger but allow circuits to be updated or added without new ceremonies. PLONK-based systems (including its variants Turbo-PLONK and Ultra-PLONK used by protocols like Aztec) support custom gates and lookup tables, enabling more efficient encoding of operations like range checks and hash functions in arithmetic circuits. On Solana, PLONK is less commonly deployed for on-chain verification than Groth16 because verification is more compute-intensive, but it is used off-chain in toolchains and protocol designs targeting future SVM upgrades with broader syscall support.

Open term

ZK Compression

ZK Compression, pioneered by Light Protocol, extends Solana's state compression model beyond NFTs to general-purpose compressed accounts by using zero-knowledge proofs (specifically Groth16 SNARKs verified via the alt_bn128 syscall) to prove the validity of state transitions without storing full account state on-chain. Compressed accounts live in on-chain Merkle trees but their data is reconstructed from the Solana ledger by indexers like Photon, enabling developers to build applications that use thousands of accounts at a fraction of the normal rent cost — often 1,000x to 5,000x cheaper than regular accounts. The protocol introduces compressed tokens, compressed PDAs, and a system of nullifiers to prevent double-spends while maintaining Solana's throughput.

Open term

ZK Compression

Validity Proof

In the context of ZK Compression on Solana, a validity proof is a Groth16 zk-SNARK proof that cryptographically attests to the correctness of one or more compressed account state transitions — specifically, that the consumed accounts exist as leaves in the current Merkle tree root, that the nullifiers are fresh (not previously spent), and that the new output account hashes correctly represent the post-transition state — all without the verifier needing to inspect the full account data. Validity proofs are generated off-chain by Light Protocol's prover service and submitted alongside compressed account instructions in Solana transactions, where the Light System Program verifies the proof on-chain using the alt_bn128 syscall before applying the state change. This model means Solana validators do not re-execute compressed account logic; they only verify the succinct proof, enabling high-throughput compressed state updates at minimal on-chain cost.

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ZK Compressionzkp-syscall

ZKP Syscall (alt_bn128)

The alt_bn128 syscalls are native BPF VM system calls added to the Solana runtime (via SIMD-0041 and related proposals) that expose elliptic curve operations on the BN254 curve (also known as alt_bn128) — specifically point addition, scalar multiplication, and pairing checks — enabling on-chain programs to verify Groth16 zk-SNARK proofs within practical compute unit budgets. Without these syscalls, implementing the pairing-based verification of a Groth16 proof purely in BPF bytecode would require hundreds of millions of compute units, far exceeding the 1.4M per-transaction limit; with the syscalls, a full Groth16 verification costs on the order of 200,000–400,000 compute units. Light Protocol's on-chain verifier and Solana's Token-2022 Confidential Transfers both depend on the alt_bn128 syscalls, making them a critical piece of Solana's ZK infrastructure.

Aliasalt_bn128

Open term

Related terms

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ZK Compressiongroth16

Groth16

Groth16 is a highly efficient zk-SNARK proving system introduced by Jens Groth in 2016 that produces constant-size proofs (128 bytes: two G1 points and one G2 point on a pairing-friendly elliptic curve) with constant-time verification regardless of circuit complexity, making it the preferred proof system for on-chain verification where calldata and compute costs are constrained. Light Protocol uses Groth16 proofs over the BN254 curve (known as alt_bn128 in Ethereum tooling) to verify compressed account state transitions on Solana, leveraging the native alt_bn128 pairing and point-addition syscalls added to the SVM to keep verification within the per-transaction compute unit limit. The trade-off is that Groth16 requires a trusted setup ceremony per circuit, producing a structured reference string (SRS) whose security relies on participants honestly discarding their toxic waste.

Open term

ZK Compressionplonk

PLONK

PLONK (Permutations over Lagrange-bases for Oecumenical Noninteractive arguments of Knowledge) is a universal zk-SNARK proving system that requires only a single, circuit-agnostic trusted setup (a universal SRS), eliminating the need for per-circuit ceremonies required by systems like Groth16, while producing proofs that are slightly larger but allow circuits to be updated or added without new ceremonies. PLONK-based systems (including its variants Turbo-PLONK and Ultra-PLONK used by protocols like Aztec) support custom gates and lookup tables, enabling more efficient encoding of operations like range checks and hash functions in arithmetic circuits. On Solana, PLONK is less commonly deployed for on-chain verification than Groth16 because verification is more compute-intensive, but it is used off-chain in toolchains and protocol designs targeting future SVM upgrades with broader syscall support.

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ZK Compression

State Compression

State Compression is Solana's technique for storing the cryptographic fingerprint (root hash) of a Merkle tree on-chain while keeping the actual leaf data off-chain in the Solana ledger's account data logs, reducing the cost of storing large datasets by orders of magnitude. A compressed NFT collection of 1 million items costs roughly 50 SOL to mint versus ~12,000 SOL with standard SPL accounts, because only a single Concurrent Merkle Tree account occupies on-chain storage. Any data change requires updating the root hash and supplying a Merkle proof to the on-chain program, which verifies inclusion without reading the full dataset.

Open term

ZK Compression

ZK Compression, pioneered by Light Protocol, extends Solana's state compression model beyond NFTs to general-purpose compressed accounts by using zero-knowledge proofs (specifically Groth16 SNARKs verified via the alt_bn128 syscall) to prove the validity of state transitions without storing full account state on-chain. Compressed accounts live in on-chain Merkle trees but their data is reconstructed from the Solana ledger by indexers like Photon, enabling developers to build applications that use thousands of accounts at a fraction of the normal rent cost — often 1,000x to 5,000x cheaper than regular accounts. The protocol introduces compressed tokens, compressed PDAs, and a system of nullifiers to prevent double-spends while maintaining Solana's throughput.

Open term

ZK Compression

Compressed Account

A compressed account is a Solana account whose state is stored as a leaf in an on-chain Concurrent Merkle Tree rather than as a dedicated on-chain account, making it 100–1,000x cheaper to create and maintain because no rent-exempt lamport balance is required per account. Compressed accounts are identified by a hash of their data and position in the tree; to interact with one, a client must supply a Merkle proof (or rely on the canopy) showing the leaf is part of the current tree root, which the on-chain program verifies before processing the state change. Light Protocol's compressed account model supports arbitrary data, discriminators, and owner programs, making it a general-purpose replacement for expensive on-chain accounts in high-volume use cases.

Open term

ZK Compression

Concurrent Merkle Tree

A Concurrent Merkle Tree (CMT) is a specialized on-chain Solana data structure that allows multiple state updates to the same Merkle tree within a single block without conflicting, by recording a changelog buffer of recent root transitions that validators use to reconcile parallel proof submissions. A CMT is parameterized by its maximum depth (max_depth, determining tree capacity of 2^max_depth leaves), max_buffer_size (number of concurrent changes the changelog can track, directly controlling how many operations per slot the tree can safely absorb), and an optional canopy_depth. The SPL Account Compression program manages CMTs, and they are the foundational storage primitive for both Metaplex compressed NFTs and Light Protocol compressed accounts.

Open term