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Unified Diff: third_party/google-endpoints/Crypto/Random/OSRNG/nt.py

Issue 2666783008: Add google-endpoints to third_party/. (Closed)
Patch Set: Created 3 years, 11 months ago
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Index: third_party/google-endpoints/Crypto/Random/OSRNG/nt.py
diff --git a/third_party/google-endpoints/Crypto/Random/OSRNG/nt.py b/third_party/google-endpoints/Crypto/Random/OSRNG/nt.py
new file mode 100644
index 0000000000000000000000000000000000000000..c1c2f44e642d03942583d491c4c6b3bcc5ee07c1
--- /dev/null
+++ b/third_party/google-endpoints/Crypto/Random/OSRNG/nt.py
@@ -0,0 +1,74 @@
+#
+# Random/OSRNG/nt.py : OS entropy source for MS Windows
+#
+# Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net>
+#
+# ===================================================================
+# The contents of this file are dedicated to the public domain. To
+# the extent that dedication to the public domain is not available,
+# everyone is granted a worldwide, perpetual, royalty-free,
+# non-exclusive license to exercise all rights associated with the
+# contents of this file for any purpose whatsoever.
+# No rights are reserved.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+# ===================================================================
+
+
+__revision__ = "$Id$"
+__all__ = ['WindowsRNG']
+
+import winrandom
+from rng_base import BaseRNG
+
+class WindowsRNG(BaseRNG):
+
+ name = "<CryptGenRandom>"
+
+ def __init__(self):
+ self.__winrand = winrandom.new()
+ BaseRNG.__init__(self)
+
+ def flush(self):
+ """Work around weakness in Windows RNG.
+
+ The CryptGenRandom mechanism in some versions of Windows allows an
+ attacker to learn 128 KiB of past and future output. As a workaround,
+ this function reads 128 KiB of 'random' data from Windows and discards
+ it.
+
+ For more information about the weaknesses in CryptGenRandom, see
+ _Cryptanalysis of the Random Number Generator of the Windows Operating
+ System_, by Leo Dorrendorf and Zvi Gutterman and Benny Pinkas
+ http://eprint.iacr.org/2007/419
+ """
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
+ data = self.__winrand.get_bytes(128*1024)
+ assert (len(data) == 128*1024)
+ BaseRNG.flush(self)
+
+ def _close(self):
+ self.__winrand = None
+
+ def _read(self, N):
+ # Unfortunately, research shows that CryptGenRandom doesn't provide
+ # forward secrecy and fails the next-bit test unless we apply a
+ # workaround, which we do here. See http://eprint.iacr.org/2007/419
+ # for information on the vulnerability.
+ self.flush()
+ data = self.__winrand.get_bytes(N)
+ self.flush()
+ return data
+
+def new(*args, **kwargs):
+ return WindowsRNG(*args, **kwargs)
+
+# vim:set ts=4 sw=4 sts=4 expandtab:

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