save

cic/crypt/aes.py

@@ -0,0 +1,42 @@
+# standard imports
+import os
+import logging
+import hashlib
+
+from Crypto.Cipher import AES
+from Crypto.Util import Counter
+
+from .base import Encrypter
+
+logg = logging.getLogger(__name__)
+
+
+class AESCTREncrypt(Encrypter):
+
+    aes_block_size = 1 << 7
+    counter_bytes = int(128 / 8)
+
+    def __init__(self, db_dir, secret):
+        self.secret = secret
+
+
+    def key_to_iv(self, k):
+        h = hashlib.sha256()
+        h.update(k.encode('utf-8'))
+        h.update(self.secret)
+        z = h.digest()
+        return int.from_bytes(z[:self.counter_bytes], 'big') 
+
+
+    def encrypt(self, k, v):
+        iv = self.key_to_iv(k)
+        ctr = Counter.new(self.aes_block_size, initial_value=iv)
+        cipher = AES.new(self.secret, AES.MODE_CTR, counter=ctr)
+        return cipher.encrypt(v)
+       
+
+    def decrypt(self, k, v):
+        iv = self.key_to_iv(k)
+        ctr = Counter.new(self.aes_block_size, initial_value=iv)
+        cipher = AES.new(self.secret, AES.MODE_CTR, counter=ctr)
+        return cipher.decrypt(v)

cic/crypt/base.py

@@ -0,0 +1,8 @@
+class Encrypter:
+    
+    def encrypt(self, v):
+        raise NotImplementedError()
+
+
+    def decrypt(self, v):
+        raise NotImplementedError()