Changeset 322 for trunk/sandbox/jhb/oc2/rsa.py

Timestamp:

06/01/09 20:52:46 (3 years ago)

Author:

ocjhb

Message:

strenthening the random numbers; ordering coins for inspection; changing wording

Files:

• trunk/sandbox/jhb/oc2/rsa.py (modified) (2 diffs)

trunk/sandbox/jhb/oc2/rsa.py

@@ -1 +1 @@
 """RSA module
 
-!!! This is just a playground, for understanding some bits and pieces,
-this is not at all serious crypto production code!!!
-
-
-
-Module for calculating large primes, and RSA encryption, decryption,
-signing and verification. Includes generating public and private keys.
+This is a module based on the works by Sybren Stuvel, Marloes de Boer and Ivo Tamboer,
+tlslite, helped by Nils Toedtmann, done wrong by Joerg Baach ;-)
+
+This file still needs serious audit before you can trust it for anything productive
+
 """
-
-__author__ = "Sybren Stuvel, Marloes de Boer and Ivo Tamboer"
-__date__ = "2004-11-17"
 
 # NOTE: Python's modulo can return negative numbers. We compensate for
@@ -20 +15 @@
 import random    # For picking semi-random numbers
 import types
+from hashlib import sha256
 
 # Get os.urandom PRNG
 import os
 def getRandomBytes(howMany):
-    bits = howMany * 8
+    factor = 8 * 8 #bytesize time security factor
+    bits = howMany * factor
+    if bits % factor:
+        bits = bits+(16-(bits % factor))
     number = random.getrandbits(bits)
-    return numberToBytes(number)
+    bytes =  numberToBytes(number)
+    out = ''
+
+    #Assuming we haven't used a good source of randomness, but the
+    #Mersenne twister, we hash a bit to make it secure
+    while bytes:        
+        out += sha256(bytes[:factor]).digest()
+        bytes = bytes[factor:]
+    return stringToBytes(out[:howMany])
+