Add Orchard ZIP 32 test vectors

pyproject.toml

@@ -69,3 +69,4 @@ orchard_note_encryption = "zcash_test_vectors.orchard.note_encryption:main"
 orchard_poseidon = "zcash_test_vectors.orchard.poseidon:main"
 orchard_poseidon_hash = "zcash_test_vectors.orchard.poseidon:hash_test_vectors"
 orchard_sinsemilla = "zcash_test_vectors.orchard.sinsemilla:main"
+orchard_zip32 = "zcash_test_vectors.orchard.zip32:main"

zcash_test_vectors/orchard/zip32.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+import sys; assert sys.version_info[0] >= 3, "Python 3 required."
+
+from hashlib import blake2b
+
+from .key_components import FullViewingKey, ExtendedSpendingKey
+
+from ..hd_common import hardened
+from ..utils import i2leosp
+from ..output import render_args, render_tv
+
+
+class DerivedSpendingKey(object):
+    def __init__(self, extsk, depth=0, parent_tag=i2leosp(32, 0), i=0):
+        self._extsk = sk
+        self._depth = depth
+        self._parent_tag = parent_tag
+        self._i     = i
+
+    def __eq__(self, other):
+        return (self._extsk == other._extsk  and
+                self._depth == other._depth and
+                self._parent_tag == other._parent_tag and
+                self._i   == other._i)
+
+    @classmethod
+    def master(cls, S):
+        return cls(ExtendedSpendingKey(S))
+
+    def sk(self):
+        return self._extsk.data
+
+    def c(self):
+        return self._extsk.chaincode
+
+    def depth(self):
+        return self._depth
+
+    def parent_tag(self):
+        return self._parent_tag
+
+    def i(self):
+        return self._i
+
+    def fingerprint(self):
+        fvk = FullViewingKey.from_spending_key(self._extsk)
+        digest = blake2b(person=b'ZcashOrchardFVFP', digest_size=32)
+        digest.update(bytes(fvk))
+        return digest.digest()
+
+    def tag(self):
+        return self.fingerprint()[:4]
+
+    def __bytes__(self):
+        return (i2leosp(8, self.depth()) +
+                self.parent_tag() +
+                i2leosp(32, self.i()) +
+                self.c() +
+                self.sk())
+
+    def child(self, i):
+        return self.__class__(self._extsk.child(i), self.depth()+1, self.tag(), i)
+
+
+def main():
+    args = render_args()
+
+    seed = bytes(range(32))
+    m = DerivedSpendingKey.master(seed)
+    m_1h = m.child(hardened(1))
+    m_1h_2h = m_1h.child(hardened(2))
+    m_1h_2h_3h = m_1h_2h.child(hardened(3))
+
+    keys = [m, m_1h, m_1h_2h, m_1h_2h_3h]
+
+    render_tvs(args, keys)
+
+def render_tvs(args, keys):
+    test_vectors = [
+        {'sk'  : k.sk(),
+         'c'   : k.c(),
+         'xsk' : bytes(k),
+         'fp'  : k.fingerprint(),
+        }
+        for k in keys
+    ]
+
+    render_tv(
+        args,
+        'orchard_zip32',
+        (
+            ('sk',  '[u8; 32]'),
+            ('c',   '[u8; 32]'),
+            ('xsk', '[u8; 169]'),
+            ('fp',  '[u8; 32]'),
+        ),
+        test_vectors,
+    )
+
+if __name__ == '__main__':
+    main()