Cold Storage Audit
Focused assessment of air-gapped and hardware-isolated storage setups, including device lifecycle planning and environmental risk factors.
Seoul · Private Clients · Since 2019
Your Bitcoin Archive Deserves a Second Pair of Eyes
App Brook Field conducts independent, long-term reviews of offline wallet archives — seed phrase custody, hardware redundancy, and recovery documentation — for holders who intend to keep bitcoin across decades.
What We Review
Archive Reviews for Long-Horizon Holders
Recovery Documentation Review
Evaluation of written recovery instructions intended for family members or executors who may need to access your bitcoin archive without prior technical knowledge.
Wallet Archive Review
A comprehensive, in-person examination of your complete offline bitcoin archive — seed phrases, hardware wallets, passphrase storage, and recovery instructions.
Why Holders Come to Us
Decades of Custody Require Documentation That Holds Up
Most bitcoin loss happens not from market moves but from forgotten passphrases, incomplete recovery notes, or hardware that outlives its manufacturer. Our reviews examine what you have on paper, in steel, and in sealed storage — and identify gaps before they become irreversible.
We work with a small number of private clients each quarter. Every engagement is conducted in person or through a secure, scheduled video session from our Yeongdeungpo office.
About App Brook Field
Client Voices
What Holders Say After Their Review
They found that my second passphrase copy was stored in the same physical location as my hardware wallet — a detail I had rationalised away for years. The written report gave my family clear steps without exposing any secrets.— K.H., Wallet Archive Review, Bundang
The session ran longer than quoted because my multisig setup had an undocumented change from 2021. I appreciated the thoroughness, though the follow-up summary took an extra week to arrive.— M.S., Cold Storage Audit, Gangnam
Field Notes
Guides from the Archive Desk
Steel vs. Paper: What We See After Ten Years in Client Archives
A comparison of seed phrase backup materials based on condition assessments during wallet archive reviews.
When Your Hardware Wallet Manufacturer Stops Support
Planning for device obsolescence before firmware updates cease and spare parts disappear.
Writing Recovery Instructions Your Spouse Can Follow
Principles for recovery documents that work when you are unavailable and the reader has no technical background.
Companion Reference
Offline Wallet Tracker
For clients who maintain a personal inventory of hardware devices, seed backups, and passphrase locations, we publish a companion reference app on the Microsoft Store. It is a private note-keeping aid — not a wallet and not connected to any network.