From c73aabd641b26988f00bd43b7c1562090fed7331 Mon Sep 17 00:00:00 2001
From: therealyingtong <yingtong@z.cash>
Date: Mon, 26 Apr 2021 22:39:00 +0800
Subject: [PATCH 1/2] Add Orchard MerkleCRH

---
 orchard_merkle_tree.py | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 orchard_merkle_tree.py

diff --git a/orchard_merkle_tree.py b/orchard_merkle_tree.py
new file mode 100644
index 0000000..c0229f3
--- /dev/null
+++ b/orchard_merkle_tree.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+import sys; assert sys.version_info[0] >= 3, "Python 3 required."
+
+from binascii import unhexlify
+
+from orchard_pallas import Fp
+from orchard_sinsemilla import sinsemilla_hash
+
+from sapling_utils import i2lebsp, leos2bsp
+
+# https://zips.z.cash/protocol/nu5.pdf#constants
+MERKLE_DEPTH = 32
+L_MERKLE = 255
+
+# https://zips.z.cash/protocol/nu5.pdf#orchardmerklecrh
+def merkle_crh(layer, left, right):
+    assert layer < MERKLE_DEPTH
+    assert len(left) == L_MERKLE
+    assert len(right) == L_MERKLE
+    l = i2lebsp(6, MERKLE_DEPTH - 1 - layer)
+    return sinsemilla_hash(b"z.cash:Orchard-MerkleCRH", l + left + right)
+
+left = unhexlify("87a086ae7d2252d58729b30263fb7b66308bf94ef59a76c9c86e7ea016536505")[::-1]
+right = unhexlify("a75b84a125b2353da7e8d96ee2a15efe4de23df9601b9d9564ba59de57130406")[::-1]
+
+left = leos2bsp(left)[:L_MERKLE]
+right = leos2bsp(right)[:L_MERKLE]
+
+# parent = merkle_crh(MERKLE_DEPTH - 1 - 25, left, right)
+parent = Fp(17261766847362299889572407272882432634088514578301422827180452043349931590033)
+assert merkle_crh(MERKLE_DEPTH - 1 - 25, left, right) == parent
+assert merkle_crh(MERKLE_DEPTH - 1 - 26, left, right) != parent

From 5a820ad1130137df21b2650857339f456ea67925 Mon Sep 17 00:00:00 2001
From: Daira Hopwood <daira@jacaranda.org>
Date: Thu, 6 May 2021 16:11:25 +0100
Subject: [PATCH 2/2] Fix length of layer prefix in orchard_merkle_tree.py.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
---
 orchard_merkle_tree.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/orchard_merkle_tree.py b/orchard_merkle_tree.py
index c0229f3..2cd8fe0 100644
--- a/orchard_merkle_tree.py
+++ b/orchard_merkle_tree.py
@@ -17,7 +17,7 @@ def merkle_crh(layer, left, right):
     assert layer < MERKLE_DEPTH
     assert len(left) == L_MERKLE
     assert len(right) == L_MERKLE
-    l = i2lebsp(6, MERKLE_DEPTH - 1 - layer)
+    l = i2lebsp(10, MERKLE_DEPTH - 1 - layer)
     return sinsemilla_hash(b"z.cash:Orchard-MerkleCRH", l + left + right)
 
 left = unhexlify("87a086ae7d2252d58729b30263fb7b66308bf94ef59a76c9c86e7ea016536505")[::-1]
@@ -27,6 +27,6 @@ left = leos2bsp(left)[:L_MERKLE]
 right = leos2bsp(right)[:L_MERKLE]
 
 # parent = merkle_crh(MERKLE_DEPTH - 1 - 25, left, right)
-parent = Fp(17261766847362299889572407272882432634088514578301422827180452043349931590033)
+parent = Fp(626278560043615083774572461435172561667439770708282630516615972307985967801)
 assert merkle_crh(MERKLE_DEPTH - 1 - 25, left, right) == parent
 assert merkle_crh(MERKLE_DEPTH - 1 - 26, left, right) != parent