add unit test module for encryption layer

diff --git a/testing/test_crypto.py b/testing/test_crypto.py
new file mode 100644 (file)
index 0000000..9406c9a
--- /dev/null
+++ b/testing/test_crypto.py
@@ -0,0 +1,82 @@
+import binascii
+import os
+import pylibscrypt
+import unittest
+
+import deltatar.crypto as crypto
+
+def b(s):
+    return s.encode("UTF-8")
+
+TEST_PLAINTEXT    = b("gentlemen don’t read each other’s mail")
+TEST_PASSPHRASE   = b"test1234"
+TEST_AES_GCM_AAD  = b"authenticated plain text"
+
+CRYPTO_NACL_SIZE  = 12
+CRYPTO_KEY_SIZE   = 16
+CRYPTO_TAG_SIZE   = 16
+
+def faux_hdr (ctsize=1337, iv=None):
+    return \
+        {      "version" : 42
+        , "paramversion" : 2187
+        ,         "nacl" : binascii.unhexlify(b"0011223344556677"
+                                              b"8899aabbccddeeff")
+        ,           "iv" : iv or binascii.unhexlify(b"0011223344556677"
+                                                    b"8899aabb")
+        ,       "ctsize" : ctsize
+        }
+
+
+def faux_payload ():
+    return "abcd" * 42
+
+class CryptoLayerTest (unittest.TestCase):
+
+    def test_crypto_aes_gcm_enc_simple (self):
+        NaCl = os.urandom (CRYPTO_NACL_SIZE)
+        key  = os.urandom (CRYPTO_KEY_SIZE)
+        enc = crypto.AES_GCM_context (crypto.ENCRYPT, key, TEST_AES_GCM_AAD)
+
+    def test_crypto_aes_gcm_enc_tag_retrieve (self):
+        NaCl = os.urandom (CRYPTO_NACL_SIZE)
+        key  = os.urandom (CRYPTO_KEY_SIZE)
+        enc = crypto.AES_GCM_context (crypto.ENCRYPT, key, TEST_AES_GCM_AAD)
+        ok, ct = enc.encrypt_chunk (TEST_PLAINTEXT)
+        if ok is False or ct is None:
+            raise "error encrypting chunk [%s]" % TEST_PLAINTEXT
+        ok, ct, tag = enc.done ()
+        if ok is False or ct is None:
+            raise "error finalizing encryption"
+        if not tag:
+            raise "no tag received upon completing the encryption"
+
+    def test_crypto_aes_gcm_enc_tag_size (self):
+        NaCl = os.urandom (CRYPTO_NACL_SIZE)
+        key  = os.urandom (CRYPTO_KEY_SIZE)
+        enc = crypto.AES_GCM_context (crypto.ENCRYPT, key, TEST_AES_GCM_AAD)
+        ok, ct = enc.encrypt_chunk (TEST_PLAINTEXT)
+        if ok is False or ct is None:
+            raise "error encrypting chunk [%s]" % TEST_PLAINTEXT
+        ok, ct, tag = enc.done ()
+        if ok is False or ct is None:
+            raise "error finalizing encryption"
+        if not tag:
+            raise "no tag received upon completing the encryption"
+        assert len (tag) == CRYPTO_TAG_SIZE
+
+    def test_crypto_aes_gcm_enc_chunk_size (self):
+        NaCl = os.urandom (CRYPTO_NACL_SIZE)
+        key  = os.urandom (CRYPTO_KEY_SIZE)
+        enc = crypto.AES_GCM_context (crypto.ENCRYPT, key, TEST_AES_GCM_AAD)
+        ok, ct = enc.encrypt_chunk (TEST_PLAINTEXT)
+        if ok is False or ct is None:
+            raise "error encrypting chunk [%s]" % TEST_PLAINTEXT
+        assert len (ct) == len (TEST_PLAINTEXT)
+        ok, ct, tag = enc.done ()
+        if ok is False or ct is None:
+            raise "error finalizing encryption"
+        if not tag:
+            raise "no tag received upon completing the encryption"
+        assert len (ct) == 0
+