fetchallcerts.py: calculate root hash

1 files changed, 24 insertions, 0 deletions

diff --git a/tools/certtools.py b/tools/certtools.py
index 16c2105..b132caa 100644
--- a/tools/certtools.py
+++ b/tools/certtools.py
@@ -226,3 +226,27 @@ def timing_point(timer_dict=None, name=None):
     else:
         timer_dict = {"deltatimes":[], "lasttime":t}
         return timer_dict
+
+def internal_hash(pair):
+    if len(pair) == 1:
+        return pair[0]
+    else:
+        hash = hashlib.sha256()
+        hash.update(struct.pack(">b", 1))
+        hash.update(pair[0])
+        hash.update(pair[1])
+        return hash.digest()
+
+def chunks(l, n):
+    return [l[i:i+n] for i in range(0, len(l), n)]
+
+def next_merkle_layer(layer):
+    return [internal_hash(pair) for pair in chunks(layer, 2)]
+
+def build_merkle_tree(layer0):
+    layers = []
+    current_layer = layer0
+    while len(current_layer) > 1:
+        current_layer = next_merkle_layer(current_layer)
+        layers.append(current_layer)
+    return layers