feat(zcash): seed_fingerprint client + tests - #15
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Wires the ZIP-32 §6.1 seed fingerprint binding into the python-keepkey
client to mirror the firmware-side validation.
device-protocol submodule
- URL: keepkey/device-protocol -> BitHighlander/device-protocol
(zcash work pins to fork master while seed_fingerprint sits in
long-term review for upstream; revert when upstream merges.)
- pin: d0b8d80 -> 4337c452 (BitHighlander/master with PR #27 merged).
- messages_zcash_pb2.py regenerated via docker_build_pb.sh
(kktech/firmware:v8 → libprotoc 3.5.1, the canonical toolchain).
Selective regen — other pb2 files are intentionally NOT
regenerated because they currently include content from
BitHighlander/device-protocol open PRs (#18 SolanaTokenInfo,
#19 TRON clear-signing, #20 TON clear-signing, #21
EthereumTxMetadata). Until those merge, regenerating them
against current master would back out work that the existing
python-keepkey client relies on.
keepkeylib/zcash.py (new)
calculate_seed_fingerprint(seed) -> 32 bytes
Pure-Python helper. BLAKE2b-256("Zcash_HD_Seed_FP",
I2LEBSP_8(len) || seed). Matches the firmware C
implementation byte-for-byte and the keystone3-firmware
reference vector
seed = 000102...1f
fp = deff604c246710f7176dead02aa746f2fd8d5389f7072556dcb555fdbe5e3ae3
keepkeylib/client.py
zcash_display_address — add expected_seed_fingerprint kwarg
zcash_sign_pczt — add expected_seed_fingerprint kwarg
Both pass through unchanged when the kwarg is None
(backward compatible).
tests/test_msg_zcash_seed_fingerprint.py (new)
Pure-Python helper:
- reference vector (Keystone3 cross-check)
- rejects all-zero, all-0xFF, short, long
Device-backed:
- GetOrchardFVK returns non-empty seed_fingerprint
- fingerprint stable across accounts (bound to seed, not account)
- DisplayAddress: matching expected_seed_fingerprint succeeds,
response carries seed_fingerprint
- DisplayAddress: wrong expected_seed_fingerprint rejected
- DisplayAddress: omitting expected_seed_fingerprint still works
- SignPCZT: wrong expected_seed_fingerprint rejected before
any signing crypto runs
Addresses review of PR #15. Test structure Helper tests (no device) move to a dedicated module: tests/test_zcash_seed_fingerprint_helper.py This module deliberately does NOT import common, transport, or any protobuf bindings, so it runs on a stock dev box: pytest tests/test_zcash_seed_fingerprint_helper.py The previous file inherited common.KeepKeyTest, whose setUp wipes the device — pytest -k 'helper' was never actually offline. Client wrapper coverage Device-backed tests now go through the public client helpers (self.client.zcash_display_address(... expected_seed_fingerprint=...) and self.client.zcash_sign_pczt(... expected_seed_fingerprint=...)) rather than building raw protobuf messages with self.client.call(). Confirms the kwarg pass-through end-to-end. New test test_device_fingerprint_matches_python_helper: cross-checks the device-computed fingerprint against the python-keepkey helper for the same seed (all-allallall mnemonic, empty passphrase). Ties the firmware C, python-keepkey helper, and ZIP-32 §6.1 reference vector to the same byte-for-byte output.
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Summary
Wires the ZIP-32 §6.1 seed fingerprint binding into the python-keepkey client to mirror the firmware-side validation introduced on `keepkey-firmware:feature-zcash`.
A 32-byte stable seed identifier. Lets a host pin an FVK/address/sign-session to a specific device-seed identity.
Changes
`device-protocol` submodule
Selective proto regen — `messages_zcash_pb2.py` only
Regenerated via `docker_build_pb.sh` (kktech/firmware:v8 → libprotoc 3.5.1, the canonical toolchain). Other pb2 files intentionally NOT regenerated because they currently include content from BitHighlander/device-protocol open PRs (#18 SolanaTokenInfo, #19 TRON clear-signing, #20 TON clear-signing, #21 EthereumTxMetadata). Until those merge, regenerating against current master would back out work that the existing python-keepkey client relies on.
New helper: `keepkeylib/zcash.py`
Pure-Python `calculate_seed_fingerprint(seed) -> bytes` matching the firmware C implementation byte-for-byte and the keystone3-firmware reference vector.
Client method updates: `keepkeylib/client.py`
Tests: `tests/test_msg_zcash_seed_fingerprint.py`
Pure-Python helper tests:
Device-backed tests:
Reference vector
```
seed = 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
fp = deff604c246710f7176dead02aa746f2fd8d5389f7072556dcb555fdbe5e3ae3
```
Cross-checked with `keystone3-firmware` `rust/keystore/src/algorithms/zcash/mod.rs::test_keystore_derive_zcash_ufvk`.
Test plan
Review path
This is the fork-master review PR. After merge here, firmware `feature-zcash` bumps its `deps/python-keepkey` pin to the new fork master HEAD. A future PR will land the same content on `keepkey/python-keepkey:master` upstream alongside the corresponding `keepkey/device-protocol` PR (long-term external review).