Cryptography / Smart Contract Security2024 / Completed / Open Source

Auth-Governed Secure Vault

Off-Chain EIP-712 ECDSA Authorized Vault Protocol

01 / Context

The engineering problem.

Smart contract vaults relying solely on msg.sender or simple access modifiers are vulnerable to compromised private keys, phishing transactions, and reentrancy loops.

Overview

A cryptographic custody vault requiring cryptographic authorizations signed by a designated security signer before executing capital disbursements. Ideal for high-value operations requiring off-chain compliance or multi-party approvals.

Signature Standard: EIP-712
Replay Security: 100% Nonce Verified
Test Suite: Foundry Invariant

02 / System design

EIP-712 Typed Signature Verification & Nonce Accounting

Validates structured off-chain permits against an immutable domain separator before updating internal accounting.

Architecture / Cryptography / Smart Contract Security

[01]

SecureVault.sol: Holds ETH reserves and executes payouts only upon valid signature submission.

AuthorizationManager.sol: Verifies ECDSA recovered addresses match active authorized signer keys.

Monotonic Nonce Mapping: Tracks and invalidates used nonces to permanently prevent transaction replay attacks.

03 / Adversarial defense

Technical challenges & mitigations.

Signature Malleability in ecrecover

Utilized OpenZeppelin ECDSA library to strictly reject signatures with non-standard s-values (preventing s-malleability exploits).

Cross-Contract Reentrancy Safeguards

Maintained strict CEI ordering and nullified user allowances prior to invoking low-level .call{value: amount} transfers.

04 / Implementation

Key features.

01EIP-712 structured data hashing for transparent wallet signing
02Replay protection through per-account nonce increments and expiration timestamps
03Zero external dependency execution paths for emergency withdrawals
04Formal invariant test suite authored in Foundry

Next study / 01