Django password check in Ruby on Rails gives inconsistent password

Question

I am rewriting a Django application in Ruby on Rails and want to keep old passwords for users.

Django uses PBKDF2SHA1 as an encryption mechanism. This way I have one encrypted password

pbkdf2_sha256$10000$YsnGfP4rZ1IZ$Tpf4922MoNEjuJQA9EG2Elptyt3dMAyzBPUgmunFOW4= 

original password 2bulls

In Ruby, I use the gem PBKDF256 and base64 for validation.

 Base64.encode64 PBKDF256.dk("2bulls", "YsnGfP4rZ1IZ", 10000, 32) 

I expect

 Tpf4922MoNEjuJQA9EG2Elptyt3dMAyzBPUgmunFOW4= 

However i got

 YEfK6oUGFHdaKZMDXC0Dz8TpwsJlKfqC5vjCxjo+ldU= 

Any ideas?

UPDATE

Found code in django source if that makes more sense to you.

 class PBKDF2PasswordHasher(BasePasswordHasher): """ Secure password hashing using the PBKDF2 algorithm (recommended) Configured to use PBKDF2 + HMAC + SHA256 with 10000 iterations. The result is a 64 byte binary string. Iterations may be changed safely but you must rename the algorithm if you change SHA256. """ algorithm = "pbkdf2_sha256" iterations = 10000 digest = hashlib.sha256 def encode(self, password, salt, iterations=None): assert password assert salt and '$' not in salt if not iterations: iterations = self.iterations hash = pbkdf2(password, salt, iterations, digest=self.digest) hash = base64.b64encode(hash).decode('ascii').strip() return "%s$%d$%s$%s" % (self.algorithm, iterations, salt, hash) def verify(self, password, encoded): algorithm, iterations, salt, hash = encoded.split('$', 3) assert algorithm == self.algorithm encoded_2 = self.encode(password, salt, int(iterations)) return constant_time_compare(encoded, encoded_2) def safe_summary(self, encoded): algorithm, iterations, salt, hash = encoded.split('$', 3) assert algorithm == self.algorithm return SortedDict([ (_('algorithm'), algorithm), (_('iterations'), iterations), (_('salt'), mask_hash(salt)), (_('hash'), mask_hash(hash)), ]) 

OUTPUT:

It turns out that this problem has only an account with 2bulls being a password. Other accounts are in order. When I know the exact reason for the inconsistent password for 2bulls, I will post here.

Answer 1

If you use this 2bulls password using the following script (the same logic that Django uses for hash passwords), this is what you get (run this on the Django shell):

 >>> import base64, hashlib >>> hash = pbkdf2("2bulls","YsnGfP4rZ1IZ", 10000, 32, hashlib.sha256) >>> hash.encode('base64').strip() 'YEfK6oUGFHdaKZMDXC0Dz8TpwsJlKfqC5vjCxjo+ldU=' 

Notice how I use the same options that you use in Ruby:

 password = "2bulls" salt = "YsnGfP4rZ1IZ" iterations = 10000 dklen = 32 digest = hashlib.sha256 

Are you sure your expected hash matches the 2bulls password?

Answer 2

I just released a stone for this purpose. I also get the same result as @Daniel Aronne:

 require 'pbkdf2_password_hasher' puts Pbkdf2PasswordHasher::hash_password('2bulls','YsnGfP4rZ1IZ',10000,32) #=> "YEfK6oUGFHdaKZMDXC0Dz8TpwsJlKfqC5vjCxjo+ldU="