Remove H().

Author: dainnilsson

NEWS

@@ -1,12 +1,11 @@
 * Version 3.0.0 (unreleased)
- ** Added support for Python 3.3+
- ** utils.rand_bytes() now sources bytes from os.urandom()
+ ** Added support for Python 3.3+.
+ ** utils.rand_bytes() now sources bytes from os.urandom().
  ** utils.websafe_encode() now returns text strings (unicode() on Python 2.x,
-    str() on Python 3.x)
+    str() on Python 3.x).
+ ** utils.H() has been removed (just use hashlib.sha256() directly instead).
  ** soft.SoftU2FDevice() now stores keys, key handles and app params as text
-    strings
-
-* Version 2.3.0 (unreleased)
+    strings.
  ** Replace M2Crypto with Cryptography.
 
 * Version 2.2.1 (released 2015-09-08)

test/test_utils.py

@@ -5,8 +5,7 @@
 from u2flib_host.utils import (
     u2str,
     websafe_encode,
-    websafe_decode,
-    H,
+    websafe_decode
 )
 
 
@@ -56,14 +55,3 @@ def test_websafe_encode(self):
     def test_websafe_encode_unicode(self):
         self.assertEqual(websafe_encode(u''), u'')
         self.assertEqual(websafe_encode(u'foobar'), u'Zm9vYmFy')
-
-
-class TestH(unittest.TestCase):
-    # SHA-256 vectors adapted from http://www.nsrl.nist.gov/testdata/
-
-    def test_H(self):
-        self.assertEqual(H(b'abc'),
-            b'\xbax\x16\xbf\x8f\x01\xcf\xeaAA@\xde]\xae"#\xb0'
-            b'\x03a\xa3\x96\x17z\x9c\xb4\x10\xffa\xf2\x00\x15\xad'
-        )
-

u2flib_host/soft.py

@@ -35,7 +35,6 @@
     print("The soft U2F token requires cryptography.")
     raise
 
-from u2flib_host.utils import H
 from u2flib_host.device import U2FDevice
 from u2flib_host.constants import INS_ENROLL, INS_SIGN
 from u2flib_host.yubicommon.compat import byte2int, int2byte

u2flib_host/u2f_v2.py

@@ -26,10 +26,11 @@
 # POSSIBILITY OF SUCH DAMAGE.
 
 from u2flib_host.constants import INS_ENROLL, INS_SIGN
-from u2flib_host.utils import websafe_decode, websafe_encode, H
+from u2flib_host.utils import websafe_decode, websafe_encode
 from u2flib_host.appid import verify_facet
 from u2flib_host.yubicommon.compat import string_types
 
+from hashlib import sha256
 import json
 
 VERSION = 'U2F_V2'
@@ -55,15 +56,15 @@ def register(device, data, facet):
 
     app_id = data.get('appId', facet)
     verify_facet(app_id, facet)
-    app_param = H(app_id)
+    app_param = sha256(app_id).digest()
 
     client_data = {
         'typ': 'navigator.id.finishEnrollment',
         'challenge': data['challenge'],
         'origin': facet
     }
     client_data = json.dumps(client_data)
-    client_param = H(client_data)
+    client_param = sha256(client_data).digest()
 
     request = client_param + app_param
 
@@ -98,7 +99,7 @@ def authenticate(device, data, facet, check_only=False):
 
     app_id = data.get('appId', facet)
     verify_facet(app_id, facet)
-    app_param = H(app_id)
+    app_param = sha256(app_id).digest()
 
     key_handle = websafe_decode(data['keyHandle'])
 
@@ -109,7 +110,7 @@ def authenticate(device, data, facet, check_only=False):
         'origin': facet
     }
     client_data = json.dumps(client_data)
-    client_param = H(client_data)
+    client_param = sha256(client_data).digest()
 
     request = client_param + app_param + chr(
         len(key_handle)) + key_handle

u2flib_host/utils.py

@@ -33,8 +33,7 @@
 __all__ = [
     'u2str',
     'websafe_encode',
-    'websafe_decode',
-    'H'
+    'websafe_decode'
 ]
 
 
@@ -61,9 +60,3 @@ def websafe_encode(data):
     if isinstance(data, text_type):
         data = data.encode('ascii')
     return urlsafe_b64encode(data).replace(b'=', b'').decode('ascii')
-
-
-def H(data):
-    f = sha256()
-    f.update(data)
-    return f.digest()