class Authlogic::CryptoProviders::BCrypt
The family of adaptive hash functions (BCrypt, SCrypt, PBKDF2) is the best choice for password storage today. They have the three properties of password hashing that are desirable. They are one-way, unique, and slow. While a salted SHA or MD5 hash is one-way and unique, preventing rainbow table attacks, they are still lightning fast and attacks on the stored passwords are much more effective. This benchmark demonstrates the effective slowdown that BCrypt provides:
require "bcrypt" require "digest" require "benchmark" Benchmark.bm(18) do |x| x.report("BCrypt (cost = 10:") { 100.times { BCrypt::Password.create("mypass", :cost => 10) } } x.report("BCrypt (cost = 4:") { 100.times { BCrypt::Password.create("mypass", :cost => 4) } } x.report("Sha512:") { 100.times { Digest::SHA512.hexdigest("mypass") } } x.report("Sha1:") { 100.times { Digest::SHA1.hexdigest("mypass") } } end user system total real BCrypt (cost = 10): 37.360000 0.020000 37.380000 ( 37.558943) BCrypt (cost = 4): 0.680000 0.000000 0.680000 ( 0.677460) Sha512: 0.000000 0.000000 0.000000 ( 0.000672) Sha1: 0.000000 0.000000 0.000000 ( 0.000454)
You can play around with the cost to get that perfect balance between performance and security. A default cost of 10 is the best place to start.
Decided BCrypt is for you? Just install the bcrypt gem:
gem install bcrypt-ruby
Tell acts_as_authentic to use it:
acts_as_authentic do |c| c.crypto_provider = Authlogic::CryptoProviders::BCrypt end
You are good to go!
Public Instance Methods
This is the :cost option for the BCrpyt library. The higher the cost the more secure it is and the longer is take the generate a hash. By default this is 10. Set this to any value >= the engine's minimum (currently 4), play around with it to get that perfect balance between security and performance.
# File lib/authlogic/crypto_providers/bcrypt.rb, line 50 def cost @cost ||= 10 end
# File lib/authlogic/crypto_providers/bcrypt.rb, line 54 def cost=(val) if val < ::BCrypt::Engine::MIN_COST raise ArgumentError.new("Authlogic's bcrypt cost cannot be set below the engine's min cost (#{::BCrypt::Engine::MIN_COST})") end @cost = val end
This method is used as a flag to tell Authlogic to “resave” the password upon a successful login, using the new cost
# File lib/authlogic/crypto_providers/bcrypt.rb, line 74 def cost_matches?(hash) hash = new_from_hash(hash) if hash.blank? false else hash.cost == cost end end
Creates a BCrypt hash for the password passed.
# File lib/authlogic/crypto_providers/bcrypt.rb, line 62 def encrypt(*tokens) ::BCrypt::Password.create(join_tokens(tokens), :cost => cost) end
Does the hash match the tokens? Uses the same tokens that were used to encrypt.
# File lib/authlogic/crypto_providers/bcrypt.rb, line 67 def matches?(hash, *tokens) hash = new_from_hash(hash) return false if hash.blank? hash == join_tokens(tokens) end
Private Instance Methods
# File lib/authlogic/crypto_providers/bcrypt.rb, line 84 def join_tokens(tokens) tokens.flatten.join end
# File lib/authlogic/crypto_providers/bcrypt.rb, line 88 def new_from_hash(hash) begin ::BCrypt::Password.new(hash) rescue ::BCrypt::Errors::InvalidHash return nil end end