class ActiveRecord::Encryption::KeyGenerator

Utility for generating and deriving random keys.

Attributes

Public Class Methods

new (hash_digest_class: ActiveRecord::Encryption.config.hash_digest_class)

# 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

Public Instance Methods

derive_key_from (password, length: key_length)

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

# 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)

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*")

# 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)

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

# File activerecord/lib/active_record/encryption/key_generator.rb, line 16
def generate_random_key(length: key_length)
  SecureRandom.random_bytes(length)
end