Securing Tessera's own smart contracts up the contract staircase: eight chained blocks a contract climbs from design to production — model, access, arithmetic, reentrancy, oracles, keys, test and monitor; the vault's withdraw function fixed with checks-effects-interactions and a reentrancy guard; flaws closed on the way, from tx.origin checks and an unguarded fee setter to a flash-loan-movable price and a single admin key; and a Foundry test where a re-entry that once drained 400 ETH from a 500 ETH pool now reverts.

CY-MID-086Mid Level · Blockchain Security

Blockchain & Smart Contract Security — The Contract Staircase

A hands-on mid-level course that secures smart contracts and the applications built on them. Climb the contract staircase - eight steps: Model, Access, Arithmetic, Reentrancy, Oracles, Keys, Test, and Monitor - finding and fixing the flaws that drain funds, with real Solidity patterns and defensive checks. Strictly defensive. Four hands-on activities in every lesson.

15 hours8 chapters32 lessons225 activities8 labs

What you'll learn

Threat-model a smart contract and enforce correct access control.
Prevent arithmetic, reentrancy, and logic bugs that lose funds.
Secure oracles, keys, and external dependencies.
Test, audit, and monitor contracts in production.

Price:৳8,000