How Fireblocks Works - MPC Custody, Enclaves, HSMs and Lessons from Real Hacks
How Fireblocks secures keys with MPC-CMP, SGX and AWS Nitro co-signers and HSM Key Link, and how it compares with Safe multisig after the Bybit hack.
2026, Oct 14 —
Crypto Wallets
How a wallet turns a seed into keys and addresses, and where that process goes wrong. The category covers BIP-32 and BIP-39 derivation, the secure elements and PIN stretching inside COLDCARD and Trezor, MetaMask's stored secrets, and an entropy defect that produced seeds far weaker than intended.
Alongside the hardware are the other places keys live: multisig setups on Gnosis Safe, custody services built on AWS Nitro Enclaves, and smart contract wallets under ERC-4337 and EIP-7702, with their nonce, deployment and delegation pitfalls. Several articles are threat models rather than walkthroughs, including one on designing for an attacker who has both the device and its owner.
16 posts
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 —
Designing for Coercion - Duress PINs, Decoy Wallets and Plausible Deniability
How hardware wallets handle an attacker who has both the device and the user - duress PINs, decoy wallets, delta mode, passive wipe triggers - and where each defence stops working.
2026, Jul 31 —
When the Hardware RNG Was Not Called - Anatomy of an Entropy Defect
A wallet firmware generated seeds with far less entropy than intended because a linker resolved rng_get() to a software PRNG. How the defect worked, why XOR whitening hid it, and what catches this class of bug.
2026, Jul 31 —
COLDCARD Firmware - Architecture and Security Model
How the COLDCARD hardware wallet firmware works - the bootloader/MicroPython split, dual secure elements, PIN key stretching, trick PINs, signed firmware, and reproducible builds.
2026, Jul 31 —
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 —
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 —
Blockchain wallets on AWS with Fireblocks and Circle
Deep dive into blockchain wallets with Circle and Fireblocks and explore how they use AWS services such as AWS Nitro Enclave
2025, Jul 29 —
Bitcoin Keys 102: How Wallets Generate Seed Phrases and Private Keys
This article is a deep dive into the generation of private keys until obtaining a public address through the main related BIPs - BIP-32 and BIP-39
2025, Mar 27 —
Bitcoin Keys 101 - From seed phrase to address
This article explains the generation of private keys in Bitcoin until obtaining a public address and the different type of addresses.
2024, Oct 28 —
Trezor Crypto Wallet – Cryptography and Security
This article presents the different types of crypto wallets (hot, warm, cold) and their associated risks
2024, Oct 15 —
Crypto Wallets Explained - Types, Risks, and How to select it
This article presents the different types of crypto wallets (hot, warm, cold) and their associated risks
2024, Oct 08 —
Deep dive into MetaMask Secrets
This article focuses on the different secrets available on Metamask, one of the most used crypto wallets.
2023, Jul 20 —
How to create a multisig wallet with Gnosis Safe
This tutorial present the different steps to create a multi signature wallet with Gnosis Safe on Ethereum.
2022, Aug 12 —
