pad shamir recovered string with 0s if too small

sudssm · Jan 5, 2016 · fad67a8 · fad67a8 · DoronShapiro · Jan 8, 2016
1 parent 8798608
commit fad67a8
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/crypto/shamir_secret_sharing.py b/crypto/shamir_secret_sharing.py
@@ -1,6 +1,7 @@
 import binascii
 from secretsharing import SecretSharer
 from custom_exceptions.exceptions import SecretReconstructionError
+import nacl.secret
 
 
 def share(secret, threshold, total_shares):
@@ -35,4 +36,6 @@ def reconstruct(shares):
         secret = SecretSharer.recover_secret(shares)
     except ValueError:
         raise SecretReconstructionError
+    while len(secret) < nacl.secret.SecretBox.KEY_SIZE * 2:
+        secret = "0" + secret
     return binascii.unhexlify(secret)
diff --git a/crypto/tests/test_secret_sharing.py b/crypto/tests/test_secret_sharing.py
@@ -1,11 +1,11 @@
 import crypto.shamir_secret_sharing
 from custom_exceptions import exceptions
+from crypto.encryption import generate_key
 import pytest
 
-
+secret = generate_key()
 def test_min_shares():
     # First share
-    secret = "FOO BAR WOOHOO!"
     shares = crypto.shamir_secret_sharing.share(secret, 2, 5)
 
     # Then attempt to recover
@@ -15,7 +15,6 @@ def test_min_shares():
 
 def test_max_shares():
     # First share
-    secret = "FOO BAR WOOHOO!"
     shares = crypto.shamir_secret_sharing.share(secret, 2, 5)
 
     # Then attempt to recover
@@ -25,7 +24,6 @@ def test_max_shares():
 
 def test_invalid_share_formatting():
     # First share
-    secret = "FOO BAR WOOHOO!"
     shares = crypto.shamir_secret_sharing.share(secret, 2, 5)
 
     # Then corrupt shares