Hi, i made a test program from the SHA512 function of libjte, which stems from GNU C Library version 2.7 and is used for Jigdo ISOs. A loop of 10 million calls with a text of 80 characters, compiled -O2, ends after 4.088 seconds. That's about 2 exp 23 times faster than python-bcrypt with 2 exp 16 rounds. So the ratio (bcrypt round / SHA512) is about 2 exp 7 = 128.
SHA512 is taken as placeholder for any postprocessing of the enumerated celebrity names which the attacker might try. It looks reasonably complex to serve for this purpose here. If not other implementations of bcrypt are faster, then during enumeration this is equivalent to 20+ bits of entropy compared to a SHA512 obfuscated password with known salt. (Not full 23 bits because generation of input passwords lasts time, too, maybe longer than their SHA512 processing.) python-bcrypt consists of a thin outer python wrapper https://sources.debian.net/src/python-bcrypt/3.1.3-1/src/bcrypt/__init__.py/ and C code from OpenBSD https://sources.debian.net/src/python-bcrypt/3.1.3-1/src/_csrc/ So at least the speed of the implementation language cannot be easily surpassed by the bcrypt of an attacker. Here is the python program, Google and i wrote in the last hour: ---------------------------------------------------------------------------- bcryptedpw.py - Compute and show long and enumeration-unfriendly password from short user password. Needs package "python-bcrypt" and maybe others which were already installed on my Jessie by the wish to have a general software development system. Provided under BSD license: Use, modify, distribute as you like. ---------------------------------------------------------------------------- #!/usr/bin/python # -*- coding: utf-8 -*- import bcrypt import getpass import sys import time # Seconds how long the result shall stay visible viewtime=15 # Invisibly ask user password userpw = getpass.getpass('Your secret password, please: ') # Compute long remote password and show it print "Don't go away now ..." p = bcrypt.hashpw(userpw, '$2a$16$TO/1Wc6L2wC8SgJpgQEV9e')[-31:] print "Here it is for ", str(viewtime), " seconds:" sys.stdout.write(p) sys.stdout.flush() # Wait and then overwrite by blanks time.sleep(viewtime) sys.stdout.write("\r \n") print "Do not forget to clear your paste buffer !" ---------------------------------------------------------------------------- I know nearly nothing of python. Probably one can do this more elegantly and more safely in respect to hiding the user password and the result from spies. (But one can really ask Google like one would ask a workmate at the next programming desk. I wonder if it could teach C in a similar way.) Have a nice day :) Thomas
