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A zero-knowledge virtual machine that generates cryptographic validity proofs for Ethereum-compatible smart contract execution, enabling ZK rollups that run existing Solidity code. Vitalik Buterin's Type 1-4 classification captures the trade-off between full Ethereum equivalence (Type 1, slower proving) and modified execution (Type 4, faster proving). Major implementations include Polygon zkEVM, zkSync Era, Scroll, and Linea.

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ZK-EVM (zk-evm)
Category: Security
Definition: A zero-knowledge virtual machine that generates cryptographic validity proofs for Ethereum-compatible smart contract execution, enabling ZK rollups that run existing Solidity code. Vitalik Buterin's Type 1-4 classification captures the trade-off between full Ethereum equivalence (Type 1, slower proving) and modified execution (Type 4, faster proving). Major implementations include Polygon zkEVM, zkSync Era, Scroll, and Linea.
Aliases: zkEVM
Related: Rollup, Zero-Knowledge Proofs (ZKP)

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Rollup

A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement.

Layer 2 (L2)

Open term

Branch

Zero-Knowledge Proofs (ZKP)

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.

Groth16 PLONK

Open term

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Blockchain General

Rollup

A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement.

Open term

ZK Compression

Zero-Knowledge Proofs (ZKP)

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.

Open term

Security

ZK Coprocessor

An off-chain computation service that executes complex operations and returns results with zero-knowledge proofs of correctness verified on-chain. ZK coprocessors extend smart contract capabilities beyond gas limits by outsourcing intensive computation while maintaining trustless verification. Projects like Brevis, RISC Zero Steel, and Lagrange enable dApps to access verified off-chain computation.

Open term

Security

Missing Signer Check

A vulnerability where a program accepts an account in a privileged role (e.g., admin, authority, payer) without verifying that the account actually signed the transaction, allowing any caller to impersonate that authority by simply passing the target pubkey as an instruction account. In native Solana programs, the check requires asserting account.is_signer == true; in Anchor, the Signer<'info> type enforces this automatically. Exploitation lets an attacker bypass all access control gated on authority equality checks, making it one of the most critical and commonly audited vulnerabilities in Solana programs.

Open term

Related terms

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Blockchain Generalrollup

Rollup

A Layer 2 scaling technique that executes transactions off-chain, bundles them, and posts compressed data back to L1. Optimistic rollups assume transactions are valid and use fraud proofs for disputes (7-day challenge period). ZK rollups generate cryptographic validity proofs for every batch. Rollups inherit L1 security while providing 10-100x throughput improvement.

Open term

ZK Compressionzk-proofs

Zero-Knowledge Proofs (ZKP)

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.

Open term

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Security

Missing Signer Check

A vulnerability where a program accepts an account in a privileged role (e.g., admin, authority, payer) without verifying that the account actually signed the transaction, allowing any caller to impersonate that authority by simply passing the target pubkey as an instruction account. In native Solana programs, the check requires asserting account.is_signer == true; in Anchor, the Signer<'info> type enforces this automatically. Exploitation lets an attacker bypass all access control gated on authority equality checks, making it one of the most critical and commonly audited vulnerabilities in Solana programs.

Open term

Security

Missing Owner Check

A vulnerability where a program deserializes and trusts account data without first confirming that the account is owned by the expected program, allowing an attacker to substitute a maliciously crafted account owned by a different program whose byte layout happens to satisfy the deserialization. On Solana, every account stores a 32-byte owner field set to the program that created it; native programs must assert account.owner == &expected_program_id, while Anchor's Account<'info, T> wrapper performs this check automatically. Failure to validate ownership can lead to complete auth bypass if an attacker can construct a fake account whose data parses into a struct with elevated privileges.

Open term

Security

Arbitrary CPI

A vulnerability where a program accepts an arbitrary program account from the caller and invokes it via Cross-Program Invocation (CPI) without verifying it matches a known, trusted program ID, effectively letting an attacker substitute a malicious program that executes under the victim program's authority or manipulates accounts the victim program passes to it. A common pattern is accepting a token_program account without checking it equals spl_token::ID, so the attacker passes a lookalike program that records or drains account data. Prevention requires hard-coding or explicitly checking the program ID before every CPI call.

Open term

Security

PDA Substitution Attack

A vulnerability where a program derives a PDA internally but accepts an externally supplied account as that PDA without re-deriving and comparing the address, allowing an attacker to pass a different PDA (derived from attacker-controlled seeds) that the program will treat as legitimate. Because PDAs are deterministic, the only way to guarantee account identity is to call Pubkey::find_program_address (or equivalent) with the expected seeds inside the program and assert the result equals the supplied key. Anchor's seeds and bump constraints on the Account type automate this re-derivation and equality check.

Open term