About Secure Data
A Seoul practice for people who treat offline Bitcoin records as carefully as the coins themselves.
Why we exist
Cold storage protects keys. It does not automatically protect memory. Holders in Seoul and across Korea often keep impeccable devices yet leave address notes in mixed notebooks, chat exports, and half-finished spreadsheets. Secure Data began as a quiet response to that gap: a place to sit with your offline records and bring them into order.
We are not a wallet vendor, an exchange desk, or a custody firm. We are a ledger practice. Our work is ink, structure, and careful verification under your control.
Origin
The practice formed in Yeouido after years of informal help for acquaintances who held Bitcoin only — no altcoin portfolios, no trading desks. The same problems repeated: change addresses forgotten after a move, inheritance folders with incomplete labels, and UTXO lists that had not been reconciled since a hardware device was upgraded.
Rather than build software for those people, we built appointment-based sessions. The record stays offline with the holder. Our role ends when the pages are clear.
Working approach
- Bitcoin-only — One asset keeps vocabulary and verification habits consistent.
- Your hands on the device — We guide; we do not operate your signer alone.
- Paper first — Digital air-gapped files are optional; durable paper remains the default deliverable.
- No seed theater — Seed phrases stay out of the room unless a pre-planned air-gapped protocol requires otherwise.
People
Hae-won Park
Practice lead. Designs session worksheets and runs flagship UTXO audits. Background in records management for private clients before focusing on Bitcoin-only ledgers.
Soo-jin Lee
Registry specialist. Handles address indexes, inheritance-ready labeling, and quarterly reconciliation appointments.
Values
Confidentiality is ordinary, not theatrical. We do not publish client names. We do not photograph ledgers. We prefer smaller calendars over rushed same-day work when the address count is high. Clients who need software product support are directed elsewhere; clients who need a calm table and a clear register are why we keep the lights on in Yeouido when it rains.