Class: SCrypt::Engine

Inherits:
Object
  • Object
show all
Defined in:
lib/scrypt-ruby.rb

Overview

Password

Constant Summary collapse

DEFAULTS = 
{
  key_len: 32,
  salt_size: 32,
  max_mem: 16 * 1024 * 1024, # 16 MiB
  max_memfrac: 0.5,
  max_time: 0.2,
  cost: nil
}

Class Method Summary collapse

Class Method Details

.calibrate(options = {}) ⇒ Object

N r p “400$8$25$”



115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/scrypt-ruby.rb', line 115

def self.calibrate(options = {})
  options = DEFAULTS.merge(options)
  max_mem = options.delete :max_mem
  max_memfrac = options.delete :max_memfrac
  max_time = options.delete :max_time

  mem_limit = memtouse(max_mem, max_memfrac)
  ops_limit = [cpuperf * max_time, 32768].min
  debug "ops_limit #{ops_limit} ops"

  n, r, p = nil, 8, nil

  if ops_limit < mem_limit/32
    debug "pick based on CPU limit"
    # Set p = 1 and choose N based on the CPU limit. 
    p = 1
    max_n = ops_limit / (r * 4)
    n = 1 << (1...63).find { |i| (1 << i) > max_n / 2 }
 else
    debug "pick based on memory limit"
    # Set N based on the memory limit. */
		max_n = mem_limit / (r * 128)
    n = 1 << (1..63).find { |i| (1 << i) > max_n / 2 }

    # Choose p based on the CPU limit. */
    max_rp = [(ops_limit / 4) / (1 << n), 0x3fffffff].min
    p = max_rp / r
  end
  debug "calibrated using: N #{n} r #{r} p #{p}"
  "#{n.to_s(16)}$#{r.to_s(16)}$#{p.to_s(16)}$"
end

.calibrate!(options = {}) ⇒ Object

N r p “4000$8$4$”



105
106
107
 
# File 'lib/scrypt-ruby.rb', line 105

def self.calibrate!(options = {})
  DEFAULTS[:cost] = calibrate(options)
end

.debug(*args) ⇒ Object 



109
110
111
 
# File 'lib/scrypt-ruby.rb', line 109

def self.debug(*args)
  SCrypt.debug(*args)
end

.generate_salt(options = {}) ⇒ Object

“4000$8$4$c6d101522d3cb045”



91
92
93
94
95
96
97
98
99
100
101
 
# File 'lib/scrypt-ruby.rb', line 91

def self.generate_salt(options = {})
  options = DEFAULTS.merge(options)
  cost = options[:cost] || calibrate(options)
  salt_size = options.delete :salt_size
  salt = OpenSSL::Random.random_bytes(salt_size).unpack('H*').first.rjust(16,'0')
  if salt.length == 40
    #If salt is 40 characters, the regexp will think that it is an old-style hash, so add a '0'.
    salt = '0' + salt
  end
  cost + salt
end

.hash_secret(secret, salt, key_len = ) ⇒ Object

“400$8$26$b62e0f787a5fc373$0399ccd4fa26642d92741b17c366b7f6bd12ccea5214987af445d2bed97bc6a2”

Raises:



172
173
174
175
176
177
178
179
180
181
182
183
184
 
# File 'lib/scrypt-ruby.rb', line 172

def self.hash_secret(secret, salt, key_len = DEFAULTS[:key_len])
  raise Errors::InvalidSalt, "invalid salt" unless valid_salt? salt
  raise Errors::InvalidSecret, "invalid secret" unless valid_secret? secret

   cost = cost_from_salt(salt)
   salt_only = salt_only(salt)

   if salt_only.length == 40
     hash_secret_old(secret, salt, cost)
   else
     salt + "$" + hash_secret_new(secret, salt_only, cost, key_len)
   end
end

.hash_secret_new(secret, salt_only, cost, key_len) ⇒ Object 



166
167
168
169
 
# File 'lib/scrypt-ruby.rb', line 166

def self.hash_secret_new(secret, salt_only, cost, key_len)
  salt_only = [salt_only.sub(/^(00)+/, '')].pack('H*')
  scrypt(secret.to_s, salt_only, cost, key_len).unpack('H*').first.rjust(key_len * 2, '0')
end

.hash_secret_old(secret, salt, cost) ⇒ Object 



162
163
164
 
# File 'lib/scrypt-ruby.rb', line 162

def self.hash_secret_old(secret, salt, cost)
  salt + "$" + Digest::SHA1.hexdigest(scrypt(secret.to_s, salt, cost, 256))
end

.scrypt(plaintext_password, salt, *args) ⇒ Object

Parameters:

  • plaintext_password —

    String

  • salt —

    String

  • args (String, key_len) —

    or [n, r, p, key_len]



75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
# File 'lib/scrypt-ruby.rb', line 75

def self.scrypt(plaintext_password, salt, *args)
  key_len = args.last
  n = r = p = nil
  case args.length
  when 2
    n, r, p = args[0].split('$').map{ |x| x.to_i(16) }
  when 4
    n, r, p = args
  else
    raise ArgumentError, 'only 4 or 6 arguments allowed'
  end
  raw_encrypted_password = com.lambdaworks.crypto.SCrypt.scrypt(plaintext_password.to_s.to_java_bytes, salt.to_java_bytes, n, r, p, key_len)
  String.from_java_bytes raw_encrypted_password
end

.valid_cost?(cost) ⇒ Boolean

Returns:

  • (Boolean) 


148
149
150
 
# File 'lib/scrypt-ruby.rb', line 148

def self.valid_cost?(cost)
  !!cost.match(/^[0-9a-z]+\$[0-9a-z]+\$[0-9a-z]+\$$/)
end

.valid_salt?(salt) ⇒ Boolean

Returns:

  • (Boolean) 


153
154
155
 
# File 'lib/scrypt-ruby.rb', line 153

def self.valid_salt?(salt)
  !!salt.match(/^[0-9a-z]+\$[0-9a-z]+\$[0-9a-z]+\$[A-Za-z0-9]{16,64}$/)
end

.valid_secret?(secret) ⇒ Boolean

Returns:

  • (Boolean) 


158
159
160
 
# File 'lib/scrypt-ruby.rb', line 158

def self.valid_secret?(secret)
  secret.respond_to?(:to_s)
end