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Lead in: Secure Smart Contract Development

August 15, 2022

In our "Secure Smart Contract Development" series, we delve into the critical security aspects of smart contract development with a focus on NFT contracts. We explore a range of risks and vulnerabilities that we as developers might encounter and offer detailed strategies and best practices for mitigating these issues to enhance security and efficiency in blockchain applications.

Breaking Down: A Comprehensive Overview

This blog explores reentrancy vulnerabilities in NFT contracts, detailing both Single-Function and Cross-Function Reentrancy. It explains the risks associated with these vulnerabilities and provides developers with mitigation strategies to secure their smart contracts.

Digital signature has been widely used in smart contracts, e.g., in allowlist mint and order-book NFT marketplaces. That’s because it helps save transaction costs (off-chain sign and on-chain verification). However, the misuse of the developers also introduces risks in the NFT marketplaces. In this blog, we’d like to talk about the misuse of digital signatures in the NFT ecosystem.

About BlockSec

BlockSec is a pioneering blockchain security company established in 2021 by a group of globally distinguished security experts. The company is committed to enhancing security and usability for the emerging Web3 world in order to facilitate its mass adoption. To this end, BlockSec provides smart contract and EVM chain security auditing services, the Phalcon platform for security development and blocking threats proactively, the MetaSleuth platform for fund tracking and investigation, and MetaSuites extension for web3 builders surfing efficiently in the crypto world.

To date, the company has served over 300 esteemed clients such as MetaMask, Uniswap Foundation, Compound, Forta, and PancakeSwap, and received tens of millions of US dollars in two rounds of financing from preeminent investors, including Matrix Partners, Vitalbridge Capital, and Fenbushi Capital.

Official website: https://blocksec.com/

Official Twitter account: https://twitter.com/BlockSecTeam

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~$5.57M Lost: X100 Freezer, NEM Exploits | BlockSec Weekly
Security Insights

~$5.57M Lost: X100 Freezer, NEM Exploits | BlockSec Weekly

This weekly report covers two security incidents on Ethereum and BNB Chain from October 19 to October 25, 2026. It examines a flash-loan-funded governance takeover of X100 Freezer and a tax-settlement flaw affecting a NEM token liquidity pool on BNB Chain. Estimated losses within the report's scope total approximately $5.57M: ~$4.75M from the representative X100 transaction and ~$820K from the NEM pool incident. The total excludes separately reported follow-on X100 extractions.

~$3.87M Lost: Autheo Network, UNCX Hacks | BlockSec Weekly
Security Insights

~$3.87M Lost: Autheo Network, UNCX Hacks | BlockSec Weekly

This weekly report covers 3 security incidents from October 12 to October 18, 2026, with approximately $3.87M in total estimated losses. Autheo Network suffered a ~$1.76M private key compromise, Qubic Wallet lost ~$1.30M due to weak seed generation, and UNCX Network's Smart Token Vesting V2 contracts suffered an ~$807K accounting error across Ethereum, BNB Chain, Base, and Robinhood Chain. The highlighted UNCX analysis explains how a flawed aggregate share calculation mixed vesting tranches created at different token-to-share ratios and enabled excess withdrawals from shared pools.

What Is SEAL Certification? Operational Security Assurance for Crypto
Security Insights

What Is SEAL Certification? Operational Security Assurance for Crypto

SEAL certification provides independent assurance of crypto operational security within an agreed scope. Explore its six modules, evidence requirements, certification limits, and BlockSec's assessment process.