WizardConnect/contrib/generate-message-signing-vectors.py

#!/usr/bin/env python3
# Copyright (C) 2026 Whiterun LLC,
# This software is licensed under the GNU Lesser General Public License (LGPL), version 3.0 or later.
#
# Regenerates packages/core/src/protocols/message-signing.vectors.json.
#
# The `sign_message` extension exists to produce signatures that OTHER software
# accepts. Asserting our own construction against our own reimplementation of it
# proves nothing, so the vectors these tests run against are generated by a real
# Electron Cash install — its msg_magic, its signer, its address encoder.
#
# Usage:
#   contrib/generate-message-signing-vectors.py [EC_SITE_PACKAGES] > \
#       packages/core/src/protocols/message-signing.vectors.json
#
# EC_SITE_PACKAGES defaults to the AppImage-style layout. Electron Cash bundles
# its own interpreter, so run this with that interpreter, not the system one:
#
#   APPDIR=/opt/electron-cash \
#   LD_LIBRARY_PATH=/opt/electron-cash/usr/lib/:/opt/electron-cash/usr/lib/x86_64-linux-gnu \
#   /opt/electron-cash/usr/bin/python3.11 -s contrib/generate-message-signing-vectors.py

import binascii
import json
import sys
import base64

DEFAULT_SITE_PACKAGES = "/opt/electron-cash/usr/lib/python3.11/site-packages"

site_packages = sys.argv[1] if len(sys.argv) > 1 else DEFAULT_SITE_PACKAGES
sys.path.insert(0, site_packages)

from electroncash.bitcoin import regenerate_key, msg_magic, Hash  # noqa: E402
from electroncash.address import Address  # noqa: E402
from electroncash.version import PACKAGE_VERSION  # noqa: E402

# Fixed test keys. Key 1 is the secp256k1 generator's scalar — convenient and
# stable; the second is arbitrary, to catch anything that only works for key 1.
KEYS = {
    "one": "00" * 31 + "01",
    "arbitrary": "c96d9a1f7f1a3e5b2d84f0a7c31e6b90d5427ac8fe13b6420d9e8a7c5b3f1d2e",
}

MESSAGES = [
    ("simple", "hello"),
    ("login", "wizardconnect login nonce=8f3a21c0d4 issued=2026-08-06T10:00:00Z"),
    ("empty", ""),
    ("multibyte", "Straße 日本語 \U0001f345"),
    ("multiline", "line one\nline two\n"),
    ("whitespace", "  padded  "),
    # The compactSize length prefix widens from one byte to three at 253.
    ("compactsize_252", "a" * 252),
    ("compactsize_253", "a" * 253),
]

vectors = []
for key_name, key_hex in KEYS.items():
    key = regenerate_key(binascii.unhexlify(key_hex))
    for compressed in (True, False):
        pubkey = key.get_public_key(compressed)
        address = Address.from_pubkey(pubkey)
        for message_name, message in MESSAGES:
            signature = key.sign_message(message, compressed)
            vectors.append(
                {
                    "name": f"{key_name}/{message_name}/{'compressed' if compressed else 'uncompressed'}",
                    "privateKey": key_hex,
                    "message": message,
                    "compressed": compressed,
                    "publicKey": pubkey if isinstance(pubkey, str) else binascii.hexlify(pubkey).decode(),
                    "signature": base64.b64encode(signature).decode(),
                    "cashaddr": address.to_full_string(Address.FMT_CASHADDR),
                    "legacy": address.to_full_string(Address.FMT_LEGACY),
                    "preimageHash": binascii.hexlify(
                        Hash(msg_magic(message.encode("utf8")))
                    ).decode(),
                    "header": signature[0],
                }
            )

print(
    json.dumps(
        {
            "_provenance": {
                "generatedBy": "Electron Cash",
                "electronCashVersion": PACKAGE_VERSION,
                "regenerate": "contrib/generate-message-signing-vectors.py",
                "note": (
                    "Signatures, addresses and preimage hashes here are produced by "
                    "Electron Cash, not by this repository. They are the external "
                    "reference the sign_message extension must match. Signature bytes "
                    "are NOT portable across implementations (Electron Cash and libauth "
                    "derive the ECDSA nonce differently), so a conforming implementation "
                    "must reproduce preimageHash exactly and must VERIFY these "
                    "signatures — it will not reproduce them byte for byte."
                ),
            },
            "vectors": vectors,
        },
        indent=2,
        ensure_ascii=False,
    )
)