Solidity

The Technical Concepts Behind the 2024 Crypto Hacks

What a Solidity developer needs to follow the 2024 hacks: Safe signing and DELEGATECALL, uninitialised upgrades, approval drains, callbacks, rounding, oracles.

2026, Oct 07 —

The Technical Concepts Behind the 2023 Crypto Hacks

What a Solidity developer needs to follow the 2023 hacks: Euler self-liquidation, the Vyper lock bug, read-only reentrancy, KyberSwap ticks, MEV-Boost.

2026, Oct 07 —

The Technical Concepts Behind the 2022 Crypto Hacks

What a Solidity developer needs to follow the 2022 hacks: bridge message checks, Solana accounts, flash-loan governance, Profanity keys, CREATE replay.

2026, Oct 07 —

The Technical Concepts Behind the 2021 Crypto Hacks

What a Solidity developer needs to follow the 2021 hacks: selector collisions, share-price donations, K-check typos, token reentrancy, ECDSA nonce reuse.

2026, Oct 07 —

The Technical Concepts Behind the 2020 Crypto Hacks

What a Solidity developer needs to follow the 2020 hacks: first flash loans, ERC-777 hooks, fee-on-transfer tokens, self-transfers, msg.value in loops.

2026, Oct 07 —

The Technical Concepts Behind the 2018 Crypto Hacks

What a Solidity developer needs to follow the 2018 hacks: BEC and SMT overflows, SpankChain reentrancy, Fomo3D randomness, hot wallets, 51% and BGP attacks.

2026, Oct 07 —

The Technical Concepts Behind the 2017 Crypto Hacks

What a Solidity developer needs to follow the 2017 hacks: Parity's delegatecall wallets and self-destructed library, blockhash limits, ICO front ends.

2026, Oct 07 —

Inside Circle's UpgradableMSCA — A Modular Smart Contract Account Under ERC-6900

How Circle's UpgradableMSCA implements an ERC-6900 modular account: validation entities, hook ordering, ERC-7201 storage, and the factory that deploys it.

2026, Sep 09 —

Inside Circle's SponsorPaymaster — How a Verifying Paymaster Is Built

A line-by-line reading of Circle's SponsorPaymaster, the ERC-4337 v0.7 verifying paymaster behind gasless Circle wallets, and the design choices behind it.

2026, Sep 09 —

How Centrifuge Vaults Work — Asynchronous ERC-7540 Investment on a Hub-and-Spoke Protocol

A technical walkthrough of Centrifuge V3 vaults - the ERC-7540 request lifecycle, the pool escrow reservation model, the pricing and rounding rules, and the transfer hook.

2026, Aug 18 —

Double-Entry Bookkeeping On-Chain — How the Centrifuge Hub Keeps a Multi-Chain Pool's Books

How Centrifuge implements real double-entry accounting in Solidity - debit-normal accounts, balanced journals, cross-chain snapshots, and the NAV and share price derived from them.

2026, Aug 18 —

Two Ways to Build a Permissioned Token — Centrifuge's Transfer Hook Against ERC-3643

A comparison of two enforcement architectures for regulated tokens - Centrifuge's single swappable hook with packed eligibility data, and ERC-3643's identity registry plus compliance modules.

2026, Aug 18 —

Centrifuge Cross-Chain Messaging — Per-Pool Adapter Quorums, Batching and Failure Recovery

How Centrifuge routes messages between chains - per-pool adapter sets, an n-of-m vote counter that tolerates duplicates, transient batching, gas subsidies, and the recovery paths.

2026, Aug 18 —

How Alchemy Implements Smart Wallets and Account Abstraction

A walkthrough of Alchemy's ERC-4337 stack — Modular Account V2 and its semi-modular variants, validation selection through the UserOperation nonce, deferred actions, session-key permission modules, the Rundler bundler, and the hosted Wallet APIs.

2026, Jul 30 —

Medusa — Architecture and Practical Use of a Coverage-Guided Solidity Fuzzer

How Medusa fuzzes Solidity contracts. Architecture, the corpus and coverage feedback loop, assertion, property and optimization tests, and a step-by-step setup on a real project.

2026, Jul 28 —

Gnosis Conditional Tokens — Combinatorial Prediction Markets on ERC-1155

How the Gnosis Conditional Tokens contracts model prediction markets, why collection identifiers are elliptic curve points on alt_bn128, and what the 2019 audit found.

2026, Jul 28 —

SenderCreator in ERC-4337 — Deploying Accounts and Reading Counterfactual Addresses

How the ERC-4337 SenderCreator contract deploys smart accounts on behalf of the EntryPoint, how third parties read counterfactual addresses through getSenderAddress, and what changed across EntryPoint v0.6 to v0.9.

2026, Jul 23 —

Integrating Pyth Network Price Feeds — A Security-Focused Guide

Learn how to integrate Pyth Network pull oracle price feeds in Solidity and Solana programs, with a deep focus on security pitfalls — staleness, confidence intervals, fixed-point math, and adversarial selection.

2026, Mar 13 —

Technical Analysis of the OpenZeppelin ERC-7984 Implementation

A deep technical analysis of the OpenZeppelin ERC-7984 Confidential Fungible Token implementation, covering the core accounting model, FHE-safe arithmetic, ACL access patterns, operator system, and the extension ecosystem.

2026, Feb 24 —

Solidity Modifier Patterns: Gas, Bytecode Size, and Security Trade-offs

A technical comparison of Solidity modifier patterns — inline, wrapped function, and no-modifier — analyzing gas costs, bytecode size impact, auditability, and conventions across major codebases.

2026, Feb 18 —

Nonce Management and CREATE2 in ERC-4337 Smart Wallets

Understanding the dual nonce system in ERC-4337 smart wallets, the differences between CREATE and CREATE2 for contract deployment, and the pitfalls encountered with EIP-7702 delegation.

2026, Feb 17 —

EIP-7702 Smart Wallet Security: Threat Model and Attack Surface Analysis

A practical security analysis of EIP-7702 smart wallets covering initialization front-running, access control, signature replay, dual nonce systems, and residual risks inherent to EOA code delegation.

2026, Feb 17 —

ERC-20 Implementation Comparison — OpenZeppelin, Solady, and Solarity Solidity Library

A technical comparison of ERC-20 token implementations across OpenZeppelin Contracts, Solady, and Solarity solidity-lib. Covers features, gas efficiency, architecture, extensibility, and selection criteria.

2026, Feb 13 —

ERC-1271 and ERC-7913 Signature Verification — OpenZeppelin, Solady, Coinbase Smart Wallet, and Solarity Solidity Library

A technical comparison of ERC-1271 and ERC-7913 signature verification across OpenZeppelin v5.5.0, Solady v0.1.26, Coinbase Smart Wallet v1.1.0, and Solarity solidity-lib v3.3.2. Covers architecture, features, gas, and selection criteria.

2026, Feb 13 —

Flexible Access Control in smart contracts (CMTAT)

This article describes how CMTAT implements flexible access control by separating business logic from authorization policy, allowing deployments to choose between RBAC, ownership, OpenZeppelin AccessManager, or custom policies.

2026, Jan 27 —

OpenZeppelin ERC-4337 Account contract Overview

This article is an overview of the OpenZeppelin ERC-4337 Account contract. The content is mainly based on the OpenZeppelin documentation.

2025, Dec 13 —

Solidity Verifier Contract - Security Checklist

This article summarizes the essential points to verify when reviewing a Solidity verifier contract using in zk-proof systems

2025, Nov 28 —

Tornado Cash Circuits - Overview

Tornado Cash is one of Ethereum’s pioneering privacy protocols build on zk-SNARK and Circom zero-knowledge circuits.

2025, Nov 19 —

Solidity ABI Encoding – Overview

This article presents the differences between abi.encode, abi.encodePacked, and abi.encodeWithSignature in Solidity. Use cases, examples, and security tips.

2025, Jul 29 —

OpenZeppelin v5 Data - Overview

This article explores data structures in OpenZeppelin Contracts v5, including EnumerableSet, DoubleEndedQueue, CircularBuffer, Checkpoints, Heap, and MerkleTree.

2025, Jul 29 —

Cyfrin First Fight 44 - Beatland Festival

Cyfrin First Fight 44 - Beatland Festival.

2025, Jul 11 —

Cyfrin First Fight 39 - Order Book

First Fight 43 - Order Book.

2025, Jul 11 —

Cyfrin First Fight 42 - Snowman Merkle Airdrop

First Fight 42 - Snowman Merkle Airdrop.

2025, Jul 11 —

Cyfrin First Fight 41 - SSSwap

First Fight 41 - SSSwap is aimed to be a minimalistic AMM on Solana.

2025, Jul 11 —

Cyfrin First Fight 40 - Weather Witness

First Fight 40 - Weather Witness.

2025, Jul 11 —

Cyfrin First Fight 39 - Hawk High

First Fight 39 - Hawk High.

2025, Jul 11 —

Cyfrin First Fight 38 - Rock Paper Scissors

First Fight 38 - Rock Paper Scissors DApp is a fully decentralized implementation of the classic Rock Paper Scissors game on Ethereum.

2025, May 07 —

Cross-chain tokens Standard (ERC-7281, xERC20) - Overview

This article presents the different standards to represent cross-chain token on Ethereum and EVM blockchain, notably ERC-7281(xERC20) & ERC-7802

2025, May 07 —

ERC-4337: Account Abstraction Using Alt Mempool

This article presents a global overview of ERC-4337 which offers Account Abstraction on Ethereum using Alt Mempool and an entrypoint.

2025, May 02 —

Multicall in Solidity: CALL vs DELEGATECALL Explained

Discover how Multicall enables batch execution of smart contract calls, when to use CALL vs DELEGATECALL, and how contract interactions differ from EOAs.

2025, Apr 03 —

ERC-721 (NFT) Overview: Implementation, Security, and Best Practices

This article presents a global overview of ERC-721 standard (NFT), covering its core functions, metadata, and security best practices and to build it with OpenZeppelin.

2025, Mar 03 —

Ethereum NFT Standards: ERC-721, ERC-1155, ERC-6551, and More

Non-Fungible Tokens (NFTs) enable unique, verifiable ownership of digital and real-world items on the blockchain. While ERC-721 remains the main standard to represent NFTs on Ethereum and EVM blockchains, several other standards (ERC-1155, ERC-2981, ERC-4907,...) have emerged to meet various use cases and improve functionality.

2025, Jan 14 —