BIP-322 signing

Every OrangeCheck sibling signs the canonical message via BIP-322 ("Generic Signed Message Format"). This page explains why that specific scheme, what wallets support it, and how to validate a signature in the two reference languages.

Why BIP-322 specifically

The older scheme — Bitcoin Core's legacy signmessage RPC, circa 2012 — only works for P2PKH addresses (1… on mainnet, m…/n… on testnet). It doesn't handle SegWit (bc1q…), Taproot (bc1p…), or P2SH wrappers.

BIP-322 fixes this: it specifies a signing scheme that works for every standard script type, including the ones you'll actually see in 2026 wallets. It does this by building a virtual "to-sign" transaction that spends a virtual "to-spend" transaction, and signing the to-sign with the key that controls the address.

If BIP-322 hadn't existed, OrangeCheck would have had to invent something like it. Since it does exist and has real wallet support, we use it.

What the wallet signs

The wallet signs the byte-exact canonical message (see canonical message). The wallet does not sign a hash of the message, does not strip whitespace, does not trim trailing newlines — it signs the raw bytes you pass it.

This is critical: any canonicalization or trimming the wallet does would cause the signature to validate against different bytes than the verifier uses when recomputing the attestation ID, and the whole chain breaks.

Wallet support matrix

Wallet	Type	BIP-322 support
UniSat	browser extension	✅ all address types
Xverse	browser + mobile	✅ all address types
Leather	browser	✅ all address types
Alby	browser	✅ all address types
Sparrow	desktop	✅ via "Sign message" (right-click an address)
Bitcoin Core	desktop + CLI	⚠ BIP-322 for P2WPKH / P2TR via `signmessage` — version-dependent
Electrum	desktop	❌ legacy scheme only (no BIP-322 for SegWit)
Hardware wallets (Coldcard / Trezor / Ledger)	HW	⚠ via PSBT flow — not a one-click signing experience

If your wallet isn't on the list, the canonical test is: does signing a message produce an output that bip322-js accepts? If yes, it works.

Error: `sig_unsupported_script`

A common failure mode: the wallet produces a legacy signature for a SegWit or Taproot address. Legacy signatures only validate for P2PKH, so the verifier correctly refuses them.

Fix: use a BIP-322-capable wallet (see above), or switch to a P2PKH address (1… on mainnet) if your wallet only supports the legacy scheme.

Verifying a BIP-322 signature

TypeScript

import { Verifier } from 'bip322-js';

const valid = Verifier.verifySignature(
    address, // bc1q... or bc1p... or 1...
    canonicalMsg, // exact bytes the wallet signed
    signatureBase64
);

bip322-js wraps the audited bitcoinjs-lib signature check. It's what @orangecheck/sdk uses internally.

Python

from orangecheck import verify_bip322_signature

valid = verify_bip322_signature(address, canonical_msg, signature_base64)

The Python SDK bridges the Rust-backed bip322 package, which in turn wraps bitcoin + secp256k1 — the same audited crates the Rust Bitcoin ecosystem runs on. Install the verification path with:

pip install 'orangecheck[verify]'

Signatures are base64, not hex

Every reference SDK accepts base64-encoded BIP-322 "simple" signatures. Some wallets hand you hex by default; convert to base64 before passing it to the verifier. The TypeScript SDK auto-detects hex and converts; the Python SDK is strict.