Ruby on Rails: Why does the user's encrypted password get changed in the DB when I use the “toggle” method on the admin attribute?

Question

I just finished Hartl\'s Rails Tutorial book and I\'m using his account authentication logic in my first rails app. However, when I make a new user account and set it as an

Answer 1

There's something odd going on in your code. A salt should be independent of the password, but your (Hartl's?) make_salt method says:

def make_salt
  secure_hash("#{Time.now.utc}--#{password}")      
end

This might have been the source of your nil problem, since you were accessing password inside make_salt; in any case this is bad crypto since it amounts to using Time.now as a "random" salt, which is much easier to crack (build rainbow tables for).

You should instead be using a good random number generator, e.g. Ruby's built-in SecureRandom:

def make_salt
  SecureRandom.hex(64)
end

Why such a long salt? According to https://crackstation.net/hashing-security.htm, "To make it impossible for an attacker to create a lookup table for every possible salt, the salt must be long. A good rule of thumb is to use a salt that is the same size as the output of the hash function. For example, the output of SHA256 is 256 bits (32 bytes), so the salt should be at least 32 random bytes." I don't want to use SecureRandom.random_bytes(32) to avoid potential database string encoding problems with non-ascii characters, and 64 random hex characters comprise 32 random bytes, which I think counts as the same entropy.