Add crypto submodule that handles AES-256-CTR encryption.

1 files changed, 80 insertions, 0 deletions

diff --git a/src/leap/common/tests/test_crypto.py b/src/leap/common/tests/test_crypto.py
new file mode 100644
index 0000000..b704c05
--- /dev/null
+++ b/src/leap/common/tests/test_crypto.py
@@ -0,0 +1,80 @@
+## -*- coding: utf-8 -*-
+# test_crypto.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+"""
+Tests for the crypto submodule.
+"""
+
+
+from leap.common.testing.basetest import BaseLeapTest
+from leap.common import crypto
+from Crypto import Random
+
+
+class CryptoTestCase(BaseLeapTest):
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_encrypt_decrypt_sym(self):
+        # generate 256-bit key
+        key = Random.new().read(32)
+        iv, cyphertext = crypto.encrypt_sym(
+            'data', key,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertTrue(cyphertext is not None)
+        self.assertTrue(cyphertext != '')
+        self.assertTrue(cyphertext != 'data')
+        plaintext = crypto.decrypt_sym(
+            cyphertext, key, iv=iv,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertEqual('data', plaintext)
+
+    def test_decrypt_with_wrong_iv_fails(self):
+        key = Random.new().read(32)
+        iv, cyphertext = crypto.encrypt_sym(
+            'data', key,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertTrue(cyphertext is not None)
+        self.assertTrue(cyphertext != '')
+        self.assertTrue(cyphertext != 'data')
+        iv += 1
+        plaintext = crypto.decrypt_sym(
+            cyphertext, key, iv=iv,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertNotEqual('data', plaintext)
+
+    def test_decrypt_with_wrong_key_fails(self):
+        key = Random.new().read(32)
+        iv, cyphertext = crypto.encrypt_sym(
+            'data', key,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertTrue(cyphertext is not None)
+        self.assertTrue(cyphertext != '')
+        self.assertTrue(cyphertext != 'data')
+        wrongkey = Random.new().read(32)  # 256-bits key
+        # ensure keys are different in case we are extremely lucky
+        while wrongkey == key:
+            wrongkey = Random.new().read(32)
+        plaintext = crypto.decrypt_sym(
+            cyphertext, wrongkey, iv=iv,
+            method=crypto.EncryptionMethods.AES_256_CTR)
+        self.assertNotEqual('data', plaintext)