Fix previous commit (pushed empty file).

1 files changed, 29 insertions, 0 deletions

diff --git a/crypto.py b/crypto.py
new file mode 100644
index 0000000..c5d28d2
--- /dev/null
+++ b/crypto.py
@@ -0,0 +1,29 @@
+from Crypto.Cipher import AES
+import os
+
+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