Add chachapoly tests.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

tests/pico-hsm/test_051_chachapoly.py

@@ -0,0 +1,126 @@
+"""
+/*
+ * This file is part of the Pico HSM distribution (https://github.com/polhenarejos/pico-hsm).
+ * Copyright (c) 2022 Pol Henarejos.
+ *
+ * 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, version 3.
+ *
+ * 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/>.
+ */
+"""
+
+import pytest
+import os
+from cryptography.hazmat.primitives.ciphers import aead
+import cryptography.exceptions
+from picohsm import APDUResponse, DOPrefixes, EncryptionMode, SWCodes
+from picohsm.const import DEFAULT_DKEK_SHARES
+from const import DEFAULT_DKEK
+from binascii import hexlify
+
+MESSAGE = b'a secret message'
+AAD = b'this is a tag for AAD'
+
+def test_prepare_chachapoly(device):
+    device.initialize(dkek_shares=DEFAULT_DKEK_SHARES)
+    resp = device.import_dkek(DEFAULT_DKEK)
+    resp = device.import_dkek(DEFAULT_DKEK)
+
+def generate_key(device):
+     # ChaCha uses 32 bytes key
+    pkey = os.urandom(256 // 8)
+    keyid = device.import_key(pkey)
+    return pkey, keyid
+
+
+def test_cipher_chachapoly_cipher(device):
+    iv = b'\x00'*12
+    pkey, keyid = generate_key(device)
+
+    ctd = device.chachapoly(keyid, EncryptionMode.ENCRYPT, data=MESSAGE, aad=AAD)
+
+    chacha = aead.ChaCha20Poly1305(pkey)
+    ctg = chacha.encrypt(iv, MESSAGE, AAD)
+    assert(bytes(ctd) == ctg)
+
+    pld = device.chachapoly(keyid, EncryptionMode.DECRYPT, data=ctd, aad=AAD)
+
+    plg = chacha.decrypt(iv, ctg, AAD)
+    device.delete_file(DOPrefixes.KEY_PREFIX, keyid)
+    assert(bytes(pld) == plg)
+    assert(bytes(pld) == MESSAGE)
+
+def test_cipher_chachapoly_random_iv(device):
+    pkey, keyid = generate_key(device)
+    iv = os.urandom(12)
+    ctd = device.chachapoly(keyid, EncryptionMode.ENCRYPT, data=MESSAGE, iv=iv, aad=AAD)
+
+    chacha = aead.ChaCha20Poly1305(pkey)
+    ctg = chacha.encrypt(iv, MESSAGE, AAD)
+    assert(bytes(ctd) == ctg)
+
+    pld = device.chachapoly(keyid, EncryptionMode.DECRYPT, data=ctd, iv=iv, aad=AAD)
+
+    plg = chacha.decrypt(iv, ctg, AAD)
+    device.delete_file(DOPrefixes.KEY_PREFIX, keyid)
+    assert(bytes(pld) == plg)
+    assert(bytes(pld) == MESSAGE)
+
+def test_cipher_chachapoly_no_aad(device):
+    pkey, keyid = generate_key(device)
+    iv = os.urandom(12)
+    ctd = device.chachapoly(keyid, EncryptionMode.ENCRYPT, data=MESSAGE, iv=iv)
+
+    chacha = aead.ChaCha20Poly1305(pkey)
+    ctg = chacha.encrypt(iv, MESSAGE, b'')
+    assert(bytes(ctd) == ctg)
+
+    pld = device.chachapoly(keyid, EncryptionMode.DECRYPT, data=ctd, iv=iv)
+
+    plg = chacha.decrypt(iv, ctg, b'')
+    device.delete_file(DOPrefixes.KEY_PREFIX, keyid)
+    assert(bytes(pld) == plg)
+    assert(bytes(pld) == MESSAGE)
+
+def test_cipher_chachapoly_bad_random_iv(device):
+    pkey, keyid = generate_key(device)
+    iv = os.urandom(12)
+    ctd = device.chachapoly(keyid, EncryptionMode.ENCRYPT, data=MESSAGE, iv=iv, aad=AAD)
+
+    chacha = aead.ChaCha20Poly1305(pkey)
+    ctg = chacha.encrypt(iv, MESSAGE, AAD)
+    assert(bytes(ctd) == ctg)
+
+    iv = os.urandom(12)
+    with pytest.raises(APDUResponse) as e:
+        pld = device.chachapoly(keyid, EncryptionMode.DECRYPT, data=ctd, iv=iv, aad=AAD)
+    assert (e.value.sw == SWCodes.SW_WRONG_DATA)
+
+    with pytest.raises(cryptography.exceptions.InvalidTag):
+        plg = chacha.decrypt(iv, ctg, AAD)
+    device.delete_file(DOPrefixes.KEY_PREFIX, keyid)
+
+def test_cipher_chachapoly_bad_aad(device):
+    pkey, keyid = generate_key(device)
+    iv = os.urandom(12)
+    ctd = device.chachapoly(keyid, EncryptionMode.ENCRYPT, data=MESSAGE, iv=iv, aad=AAD)
+
+    chacha = aead.ChaCha20Poly1305(pkey)
+    ctg = chacha.encrypt(iv, MESSAGE, AAD)
+    assert(bytes(ctd) == ctg)
+
+    with pytest.raises(APDUResponse) as e:
+        pld = device.chachapoly(keyid, EncryptionMode.DECRYPT, data=ctd, iv=iv, aad=AAD + b'bad')
+    assert (e.value.sw == SWCodes.SW_WRONG_DATA)
+
+    with pytest.raises(cryptography.exceptions.InvalidTag):
+        plg = chacha.decrypt(iv, ctg, AAD + b'bad')
+    device.delete_file(DOPrefixes.KEY_PREFIX, keyid)