Complete rewite of crypto.py

crypto.py now uses keyczar. The examples are now much more
representative of the type of encryptions in alias

1 files changed, 26 insertions, 27 deletions

diff --git a/crypto.py b/crypto.py
index c5d28d2..b575f55 100644
--- a/crypto.py
+++ b/crypto.py
@@ -1,29 +1,28 @@
-from Crypto.Cipher import AES
-import os
+from keyczar import keys
+import ssh_rsa_key_util
 
-def encrypt(msg,key,block_size):
-    pad = block_size - len(msg) % block_size
-    data = msg + pad * chr(pad)
-    iv = os.urandom(block_size)
-    cipheredtext = iv + AES.new(key, AES.MODE_CBC, iv).encrypt(data)
-    return cipheredtext
-
-def decrypt(cipheredtext,key,block_size):
-    iv = cipheredtext[:block_size]
-    msg = AES.new(key, AES.MODE_CBC, iv).decrypt(cipheredtext[block_size:])
-    #remove the padding
-    pad = ord(msg[-1])
-    msg = msg[:-pad] 
-    return msg
-    
 if __name__ == '__main__' :
-    block_size = 16
-    key_size = 32
-    key = os.urandom(key_size)
- 
-    msg1 = 'Guillaume is a genius!'
-    msg2 = encrypt(msg1,key,block_size)
-    msg3 = decrypt(msg2,key,block_size)
-    print "original message: " + msg1
-    print "encrypted message: " + msg2.encode('hex')
-    print 'verification: ' + msg3
+    #load asymmetric keys for 2 users. user1 key is generated,
+    #while user2 key is loaded from disk
+    keyuser1 = keys.RsaPrivateKey.Generate()
+    keyuser1public = keyuser1.public_key
+    ssh_keys_directory='/home/guillaume/.ssh/'
+    keyuser2 = ssh_rsa_key_util.SshRsaPrivateKey.Read(ssh_keys_directory + 'id_rsa')
+    keyuser2public = keyuser2.public_key
+    
+    #symmetric key to encrypt the data
+    key = keys.AesKey.Generate()
+    #encrypt symmetric key for user 1 and 2
+    key1 = keyuser1public.Encrypt(key.key_string)
+    key2 = keyuser2public.Encrypt(key.key_string)
+    
+    msg = 'Guillaume is a genius!'
+    secretmsg = key.Encrypt(msg)
+    
+    #msg decoded by user 1
+    newkey1 = keys.AesKey(keyuser1.Decrypt(key1),key.hmac_key)
+    print newkey1.Decrypt(secretmsg)
+    
+    #msg decoded by user 2
+    newkey2 = keys.AesKey(keyuser1.Decrypt(key1),key.hmac_key)
+    print newkey2.Decrypt(secretmsg)
\ No newline at end of file