added timedhmac file, not done

cryptoshim.py

@@ -0,0 +1,16 @@
+'''
+    Onionr - P2P Microblogging Platform & Social network. Run with 'help' for usage.
+    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, either version 3 of the License, or
+    (at your option) any later version.
+
+    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 <https://www.gnu.org/licenses/>.
+'''
+

timedHmac.py

@@ -0,0 +1,39 @@
+'''
+    Onionr - P2P Microblogging Platform & Social network. Run with 'help' for usage.
+    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, either version 3 of the License, or
+    (at your option) any later version.
+
+    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 <https://www.gnu.org/licenses/>.
+'''
+import hmac, base64, time, math
+class TimedHMAC:
+    def __init__(self, base64Key, data, hashAlgo):
+        '''
+        base64Key = base64 encoded key
+        data = data to hash
+        expire = time expiry in epoch
+        hashAlgo = string in hashlib.algorithms_available
+
+        Maximum of 10 seconds grace period
+        '''
+        self.data = data
+        self.expire = math.floor(time.time())
+        self.hashAlgo = hashAlgo
+        self.b64Key = base64Key
+        generatedHMAC = hmac.HMAC(base64.b64decode(base64Key).decode(), digestmod=self.hashAlgo)
+        generatedHMAC.update(data + expire)
+        self.HMACResult = generatedHMAC.hexdigest()
+        return
+
+    def check(self, data):
+        testHash = hmac.HMAC(base64.b64decode(base64Key).decode(), digestmod=self.hashAlgo)
+        testHash.update(data + math.floor(time.time()))
+        testHash = testHash.hexdigest()
+        if hmac.compare_digest(testHash, self.HMACResult)