Bitcoin self-custody, made simple and verifiable by you.
ZNTRPHY generates your Bitcoin keys (single-sig and multisig) fully offline, no account, no cloud, no network connection, with the full source code included so you or anyone you trust can audit it.
macOS available now. For Windows and Linux, build the app from the included source code.
Why ZNTRPHY exists
The most widely used tools for generating Bitcoin keys securely (Sparrow Wallet, Electrum, Specter Desktop) are excellent, free, and have years of public auditing behind them. They're also full-featured wallets with dozens of options, which isn't always the clearest path for someone who just wants to generate and store their keys securely, once, and correctly.
ZNTRPHY does one thing: generate and verify Bitcoin keys air-gapped, explained step by step, with a manual written for people who are new to self-custody. The interface and manual are available in both English and Spanish.
What's included
Single-sig and multisig
Single-key wallets, or m-of-n schemes (2-of-3, etc.), with two coordination modes depending on your use case.
100% offline
Never connects to the internet. Generate your keys on a machine disconnected from the network, verifiable by yourself.
Last-word calculator
Generated your own words by hand (e.g. with dice) and missing the last one? The app computes the options that complete a valid BIP39 checksum.
Encrypted export
Optional digital backup protected with a PIN (Argon2id and AES-256-GCM). Nothing is saved unless you explicitly ask for it.
English and Spanish
Full interface and manual in both languages, with a switcher built into the app itself.
Source code included
Nothing hidden. Audit the code yourself, or ask someone you trust to review it before using it with real funds.
Full manual
Step-by-step PDF guide: what air-gapped means, how to verify the file, and how to back up and verify your seed.
Don't take our word for it: check for yourself
- Every download includes a published SHA-256 hash so you can confirm the file wasn't modified.
- The full source code ships inside the download, no need to request it separately, and is also published on GitHub so anyone can review it before downloading anything.
- You can confirm, by reading the code yourself, that the app never imports a network module.
- We document openly what ZNTRPHY protects and what it doesn't. See
SECURITY.mdin the download or in the repository.
Official SHA-256 hash (macOS, v1.0), published here independently of the downloaded file, so you can compare it even if the zip itself were compromised:
64294c26eda78637b7945c003b1acc042ab71c38140dca8d8aac90893773d064
Corresponds to ZNTRPHY.app/Contents/MacOS/ZNTRPHY. Verify it with shasum -a 256 after extracting the zip, as explained in LEEME_PRIMERO.txt.
Download
Free
Includes macOS, full source code, and manual in English and Spanish.
Found it useful? You can send us a tip in BTC, Lightning ⚡ (totally optional):
securemiaow241@walletofsatoshi.com
Paste it into your Lightning wallet (Wallet of Satoshi, Phoenix, Muun...).
⚠️ ZNTRPHY is a desktop application (macOS, Windows, or Linux). It cannot be installed or opened on a phone or tablet. Download it from a computer.
Frequently asked questions
Does this app store my keys on any server?
No, never. ZNTRPHY never connects to the internet. You can verify this yourself by reviewing the included source code, or by running the app with the network disconnected.
Do I need to know how to code to use it?
No. The app has a guided graphical interface, with a step-by-step manual. You only need coding knowledge if you also want to audit the source code.
Does it work on Windows or Linux?
The current download includes a ready-to-run executable for macOS. For Windows or Linux, you can build the app yourself from the included source code, following the instructions in the README.
What happens if I lose my seed phrase?
You lose access to the funds forever: neither ZNTRPHY, nor fnalysis.com, nor anyone else can recover it. That's why the manual is so insistent about the backup and verification process.