Class: ActiveRecord::Encryption::KeyGenerator

Inherits:
Object
  • Object
show all
Defined in:
activerecord/lib/active_record/encryption/key_generator.rb

Overview

Utility for generating and deriving random keys.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hash_digest_class: ActiveRecord::Encryption.config.hash_digest_class) ⇒ KeyGenerator

Returns a new instance of KeyGenerator.



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# File 'activerecord/lib/active_record/encryption/key_generator.rb', line 11

def initialize(hash_digest_class: ActiveRecord::Encryption.config.hash_digest_class)
  @hash_digest_class = hash_digest_class
end

Instance Attribute Details

#hash_digest_class ⇒ Object (readonly)

Returns the value of attribute hash_digest_class.



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# File 'activerecord/lib/active_record/encryption/key_generator.rb', line 9

def hash_digest_class
  @hash_digest_class
end

Instance Method Details

#derive_key_from(password, length: key_length) ⇒ Object

Derives a key from the given password. The key will have a size in bytes of :length (configured Cipher‘s length by default)

The generated key will be salted with the value of ActiveRecord::Encryption.key_derivation_salt



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# File 'activerecord/lib/active_record/encryption/key_generator.rb', line 38

def derive_key_from(password, length: key_length)
  ActiveSupport::KeyGenerator.new(password, hash_digest_class: hash_digest_class)
    .generate_key(key_derivation_salt, length)
end

#generate_random_hex_key(length: key_length) ⇒ Object

Returns a random key in hexadecimal format. The key will have a size in bytes of :length (configured Cipher‘s length by default)

Hexadecimal format is handy for representing keys as printable text. To maximize the space of characters used, it is good practice including not printable characters. Hexadecimal format ensures that generated keys are representable with plain text

To convert back to the original string with the desired length:

[ value ].pack("H*")



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# File 'activerecord/lib/active_record/encryption/key_generator.rb', line 30

def generate_random_hex_key(length: key_length)
  generate_random_key(length: length).unpack("H*")[0]
end

#generate_random_key(length: key_length) ⇒ Object

Returns a random key. The key will have a size in bytes of :length (configured Cipher‘s length by default)



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# File 'activerecord/lib/active_record/encryption/key_generator.rb', line 16

def generate_random_key(length: key_length)
  SecureRandom.random_bytes(length)
end