OCSP request parsing (#4393)

* add public_bytes to OCSPRequest

* review feedback

* OCSP request parsing

* change some prose

* add __len__ as a required method

1 files changed, 79 insertions, 0 deletions

diff --git a/src/cryptography/x509/ocsp.py b/src/cryptography/x509/ocsp.py
new file mode 100644
index 00000000..22894dde
--- /dev/null
+++ b/src/cryptography/x509/ocsp.py
@@ -0,0 +1,79 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+from __future__ import absolute_import, division, print_function
+
+import abc
+
+import six
+
+from cryptography.hazmat.primitives import hashes
+
+
+_OIDS_TO_HASH = {
+    "1.3.14.3.2.26": hashes.SHA1(),
+    "2.16.840.1.101.3.4.2.4": hashes.SHA224(),
+    "2.16.840.1.101.3.4.2.1": hashes.SHA256(),
+    "2.16.840.1.101.3.4.2.2": hashes.SHA384(),
+    "2.16.840.1.101.3.4.2.3": hashes.SHA512(),
+}
+
+
+def load_der_ocsp_request(data):
+    from cryptography.hazmat.backends.openssl.backend import backend
+    return backend.load_der_ocsp_request(data)
+
+
+@six.add_metaclass(abc.ABCMeta)
+class OCSPRequest(object):
+    @abc.abstractmethod
+    def __iter__(self):
+        """
+        Iteration of Requests
+        """
+
+    @abc.abstractmethod
+    def __len__(self):
+        """
+        Number of Requests inside the OCSPRequest object
+        """
+
+    @abc.abstractmethod
+    def __getitem__(self, idx):
+        """
+        Returns a Request or range of Requests
+        """
+
+    @abc.abstractmethod
+    def public_bytes(self, encoding):
+        """
+        Serializes the request to DER
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class Request(object):
+    @abc.abstractproperty
+    def issuer_key_hash(self):
+        """
+        The hash of the issuer public key
+        """
+
+    @abc.abstractproperty
+    def issuer_name_hash(self):
+        """
+        The hash of the issuer name
+        """
+
+    @abc.abstractproperty
+    def hash_algorithm(self):
+        """
+        The hash algorithm used in the issuer name and key hashes
+        """
+
+    @abc.abstractproperty
+    def serial_number(self):
+        """
+        The serial number of the cert whose status is being checked
+        """