# Blockchain

Finding Real-World Bugs in Smart Contract Interactions with Property-Based Testing (Mon, Dec 14, 2020) By Mikkel Milo et al.
Category : Technical
Category : Technical

Recently, Nomadic Labs made a blog post detailing their work on formally verifying the Dexter smart contract, a contract that provides decentralized exchange of digital assets. They verified functional properties of the contract using Mi-Cho-Coq, a Coq framework for proving properties about Michelson contracts in Tezos. A key limitation of Mi-Cho-Coq is that it does not allow for proving properties about contract-to-contract communications (also referred to as inter-contract communications, or just contract interactions).

Preventing an $8M attack on Ethereum's bZx deFI platform with property-based testing (Fri, Aug 7, 2020) By Mikkel Milo et al. Category : Technical On September 12, the bZx decentralized finance (deFI) platform suffered from an attack where the attacker was able to obtain control over$8 million worth of cryptocurrency. The fault was due a single misplaced line in their iToken smart contract’s transferFrom method, allowing an attacker to duplicate their tokens, consequently allowing them to increase their token balance arbitrarily. The bug remained hidden, though, during an extensive 19 person-week auditing by two security companies, Peckshield and CertiK.