Class: ActiveSupport::KeyGenerator
Relationships & Source Files | |
Inherits: | Object |
Defined in: | activesupport/lib/active_support/key_generator.rb |
Overview
Key Generator
KeyGenerator
is a simple wrapper around OpenSSL’s implementation of PBKDF2. It can be used to derive a number of keys for various purposes from a given secret. This lets Rails applications have a single secure secret, but avoid reusing that key in multiple incompatible contexts.
Class Attribute Summary
Class Method Summary
- .new(secret, options = {}) ⇒ KeyGenerator constructor
Instance Method Summary
-
#generate_key(salt, key_size = 64)
Returns a derived key suitable for use.
Constructor Details
.new(secret, options = {}) ⇒ KeyGenerator
# File 'activesupport/lib/active_support/key_generator.rb', line 28
def initialize(secret, = {}) @secret = secret # The default iterations are higher than required for our key derivation uses # on the off chance someone uses this for password storage @iterations = [:iterations] || 2**16 # Also allow configuration here so people can use this to build a rotation # scheme when switching the digest class. @hash_digest_class = [:hash_digest_class] || self.class.hash_digest_class end
Class Attribute Details
.hash_digest_class (rw)
[ GitHub ]# File 'activesupport/lib/active_support/key_generator.rb', line 23
def hash_digest_class @hash_digest_class ||= OpenSSL::Digest::SHA1 end
.hash_digest_class=(klass) (rw)
[ GitHub ]Instance Method Details
#generate_key(salt, key_size = 64)
Returns a derived key suitable for use. The default key_size
is chosen to be compatible with the default settings of MessageVerifier
. i.e. OpenSSL::Digest::SHA1#block_length
# File 'activesupport/lib/active_support/key_generator.rb', line 41
def generate_key(salt, key_size = 64) OpenSSL::PKCS5.pbkdf2_hmac(@secret, salt, @iterations, key_size, @hash_digest_class.new) end