From 3e2b2ab8f83bf83d7e15e136280f4b20e5c78365 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Fri, 18 May 2018 13:01:01 +1200
Subject: [PATCH] Implement MerkleCRH

---
 sapling_merkle_tree.py | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 sapling_merkle_tree.py

diff --git a/sapling_merkle_tree.py b/sapling_merkle_tree.py
new file mode 100644
index 0000000..d6ad35b
--- /dev/null
+++ b/sapling_merkle_tree.py
@@ -0,0 +1,9 @@
+#!/usr/bin/env python3
+from sapling_pedersen import pedersen_hash
+from sapling_utils import i2lebsp
+
+MERKLE_DEPTH = 32
+
+def merkle_crh(layer, left, right):
+    l = i2lebsp(6, MERKLE_DEPTH - 1 - layer)
+    return pedersen_hash(b'Zcash_PH', l + left + right)