Silent Amulet

1 Your silent-payment address

Share this with senders. It never changes, and is never written on-chain.

2 Labeled addresses (optional)

Label indices ≥ 1 produce distinct sp1… addresses that still resolve to the same spend key, so you can tag senders. Index 0 is reserved by spec for change.

3 Scan for received outputs (indexer)

Silent-payment receivers can't tell which taproot outputs are theirs without reading every transaction's inputs. A Blindbit-compatible indexer exposes per-block tweak data so a light client can do this work locally.

:8000 {
  reverse_proxy 127.0.0.1:7000
  header {
    Access-Control-Allow-Origin *
    Access-Control-Allow-Methods "GET, OPTIONS"
    Access-Control-Allow-Headers *
  }
  @options method OPTIONS
  respond @options 204
}

from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.request import urlopen
from urllib.error import HTTPError, URLError
UPSTREAM = 'http://127.0.0.1:7000'
class H(BaseHTTPRequestHandler):
    def _c(self, s=200, b=b''):
        self.send_response(s)
        self.send_header('Access-Control-Allow-Origin', '*')
        self.send_header('Access-Control-Allow-Methods', 'GET, OPTIONS')
        self.send_header('Access-Control-Allow-Headers', '*')
        self.send_header('Content-Type', 'application/json')
        self.end_headers()
        if b: self.wfile.write(b)
    def do_OPTIONS(self): self._c(204)
    def do_GET(self):
        try:
            with urlopen(UPSTREAM + self.path, timeout=30) as r: self._c(r.status, r.read())
        except HTTPError as e: self._c(e.code, e.read() if e.fp else b'')
        except URLError as e: self._c(502, str(e).encode())
HTTPServer(('127.0.0.1', 8000), H).serve_forever()

Send Bitcoin to a silent payment

The quick way: paste the address, type an amount, fetch your funds, send. The numbered cards below do the very same thing step by step if you want to watch every detail.

Broadcasting from this browser shows your IP address and the transaction to the indexer you connect to. For maximum privacy, use the numbered cards below and push the signed transaction through your own node or Tor.

1 Recipient

2 Your UTXOs (inputs)

Add each UTXO you want to spend. For silent payments, only these types are eligible: P2TR-keypath (bc1p…), P2WPKH (bc1q…), P2SH-P2WPKH (3…), P2PKH (1…). Keys are used locally only.

3 Change address

BIP-352 reserves label index 0 on your own SP address for self-pay (change). When you pick the sp1… option, Silent Amulet will run a dual-recipient sender derivation — same inputs, same tweak, two distinct P2TR outputs. The bc1p… option uses x-only(B_spend) directly as a raw P2TR output, spendable by signing with your spend key.

4 Construct transaction

5 Sign transaction

Build a fully signed raw transaction in the browser using the private keys already loaded in your UTXO editor. Covers all four input types — P2TR (Schnorr, BIP-341), P2WPKH / P2SH-P2WPKH (ECDSA, BIP-143), and P2PKH (legacy ECDSA). Requires the fast-crypto backend (@noble/secp256k1) to be loaded — check the crypto pill on the Receive tab. If it's not loaded, use the PSBT above with an external signer.

6 Broadcast