₿ Monolith

Silent Payments (BIP352) · air-gapped · zero-tracker

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Monolith performs zero network I/O. All cryptography runs locally in your browser. Not a substitute for an audited hardware wallet — verify before use.

1. Wallet — Seed Phrase & Derivation

Generate a 24-word BIP39 mnemonic, optionally protect it with a passphrase, and derive the BIP352 scan and spend keys using the standard derivation paths: m/352'/0'/0'/1'/0 for the scan key and m/352'/0'/0'/0'/0 for the spend key. Write down your mnemonic. Anyone with the words can spend your funds.

BIP39 passphrase (optional, "25th word")

Leave this empty for a standard seed. If you set one, you must enter it every time you restore — BIP39 has no checksum on the passphrase, so a single wrong character silently produces a different, empty wallet.

Seed currently derived without a passphrase.

Scan key (b_scan)

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Spend key (b_spend)

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2. Silent Payment Address (reusable)

The address encodes B_scan ‖ B_spend with bech32m under the human-readable part sp, witness version 0 (so every valid address begins sp1q…). Post it anywhere — every payment lands at a fresh on-chain P2TR output that only your wallet can detect.

Checksum: — Version byte: —
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QR rendered locally as inline SVG.

Fresh receiving addresses (k indices)

Each sender derives a unique P2TR output for your silent address. The table below shows the first 8 hypothetical outputs your wallet would detect when scanning (k = 0…7). The actual outputs depend on each sender's inputs.

kDerived P2TR x-only (simulated)P2TR scriptPubKey
Generate a wallet first.
3. Sender Simulation

List each transaction input (txid, vout, input private key). The app sums the public keys, computes the shared secret against your B_scan, and derives one P2TR output per requested index.

4. Receiver Detection

Paste the summed input public key, smallest outpoint, and candidate output x-only keys. The app detects matches against your current wallet.

5. Backup & App Compatibility

This wallet uses standard BIP39 mnemonic + BIP32 derivation. Any wallet that supports BIP352 silent payments and the derivation path below can restore your funds.

Backup type
24-word BIP39 mnemonic (+ optional passphrase)
Scan path
m/352'/coin_type'/account'/1'/0
Spend path
m/352'/coin_type'/account'/0'/0
Address format
bech32m, hrp "sp", version byte 0 (sp1q…)
Compatible wallets
Cake Wallet, BitBox02, Blue Wallet (SP builds), Silentium, Shroud

How to restore in another app

  1. Install a wallet that supports BIP352 silent payments (e.g. Cake Wallet).
  2. Choose "Restore from seed" and enter your 24 words.
  3. If you used a passphrase, enter it exactly.
  4. Select the account index (default 0) to match this derivation.
  5. The wallet will scan for payments to your sp1… address.

Important caveats

6. Derivation Trace
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7. Conformance Tests
Not run yet.
#TestStatusDetail
8. Wallet Recovery Kit

Recover a Silent Payments wallet produced by this tool or by another BIP352-capable wallet (Cake, Sparrow, Silentium, BitBox02, …). Optionally match against a known sp1… address to confirm the correct derivation.

Target (optional)
Recovery method

Up to 1 missing word (brute-force is slow).

9. Paper Wallet — PDF Generator (offline, zero-tracker)

Renders a vector PDF paper wallet entirely in your browser. No fonts, images, or analytics are fetched — the PDF is generated byte-for-byte on this page and delivered as a Blob download. A4 and US Letter are supported; the public side carries your sp1q… address and B_scan / B_spend, the private side carries your 24-word mnemonic and derivation paths.

Options

Never print to a network printer. Never leave a printed paper wallet in view of a camera. Store the private side in a safe, offline place; the public side is safe to share.

Generate a wallet first.
Event Log
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About & Provenance

Monolith implements Silent Payments (BIP352) — a scheme where a sender derives a fresh P2TR output for a recipient without prior interaction. The recipient publishes one static sp1q… address and scans for outputs using their scan private key.

Inlined algorithms

Threat model

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Keyboard shortcuts

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