Layer 1 & Layer 2 Protocol Security Engineering

Zellic provides protocol-level security engineering for blockchain Layer 1 protocols, Layer 2 scaling solutions, and rollup implementations. Their protocol security experts work with some of the largest L1 blockchains including Solana Foundation, Aptos Labs, and Mysten Labs, as well as major L2 solutions like StarkNet, Scroll, and Mantle.

Protocol Security Domains

Consensus & Byzantine Fault Tolerance: Comprehensive review of consensus algorithms including proof-of-stake, proof-of-work variants, BFT implementations, and leader election mechanisms. Analysis covers safety, liveness, and resistance to adversarial conditions.

Networking Layer: Peer-to-peer networking security, transaction propagation mechanisms, block gossip protocols, and network-level attack resistance including eclipse attacks, Sybil resistance, and DDoS mitigation.

Virtual Machine Security: Deep analysis of blockchain VMs including EVM variants, Solana's runtime, Move VM (Aptos/Sui), and CosmWasm. Reviews cover bytecode verification, instruction execution safety, gas metering, and runtime invariants.

State Transition Functions: Thorough examination of block validation logic, transaction processing, state commitment schemes, and cryptographic accumulator correctness.

Custom Precompiles: Security review of custom cryptographic precompiles and native operations, ensuring correct implementation and resistance to edge case failures.

Major Protocol Discoveries

Move Bytecode Verifier Vulnerability: Zellic's most significant protocol-level discovery was a critical vulnerability in Move's bytecode verifier in 2023 that put billions of dollars at risk across Sui and Aptos. This bug could have allowed attackers to obtain multiple mutable references to an object, fundamentally breaking Move's safety guarantees.

Solana Inflationary Bug: Discovery of a critical vulnerability in Solana's Zero-Knowledge confidential token transfer functionality that would have allowed infinite minting of tokens—a potentially catastrophic protocol-level exploit.

Cosmos SDK Vulnerabilities: Identification of critical issues in Cosmos SDK including buffer overflows, non-determinism causing consensus failures, and integer overflow conditions. These protocol-level findings prevent chain halts and consensus splits.

Ecosystem-Specific Expertise

Solana Protocol: Full-stack security from runtime implementation to consensus, with direct engagement with Solana Foundation. Expertise in Solana-specific invariants including account validation, rent mechanics, and parallel transaction execution.

Cosmos/Tendermint: Deep understanding of application-specific blockchains, IBC protocol security, module composition, and non-determinism issues unique to Cosmos. Work with major Cosmos chains including Berachain, Osmosis, ZetaChain, and Nibiru.

Layer 2 Rollups: Security engineering for optimistic and ZK-rollups including state commitment schemes, fraud proof mechanisms, ZK verifier correctness, and bridge security between L1 and L2.

Why Choose Zellic

Zellic's protocol-level security engineering ensures the foundational infrastructure of Web3 is protected against vulnerabilities that could compromise network integrity, enable consensus failures, or put billions of dollars at risk. Their team's offensive security background and CTF competition success enables them to approach protocol code with an attacker mindset, finding critical issues that could affect entire blockchain ecosystems.