Class: Lockbox::Box

Inherits:
Object
  • Object
show all
Defined in:
lib/lockbox/box.rb

Constant Summary collapse

NOT_SET = 
Object.new

Instance Method Summary collapse

Constructor Details

#initialize(key: nil, algorithm: nil, encryption_key: nil, decryption_key: nil, padding: false, associated_data: nil) ⇒ Box

Returns a new instance of Box.

Raises:

  • (ArgumentError) 


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# File 'lib/lockbox/box.rb', line 5

def initialize(key: nil, algorithm: nil, encryption_key: nil, decryption_key: nil, padding: false, associated_data: nil)
  raise ArgumentError, "Cannot pass both key and encryption/decryption key" if key && (encryption_key || decryption_key)

  key = Lockbox::Utils.decode_key(key) if key
  encryption_key = Lockbox::Utils.decode_key(encryption_key, size: 64) if encryption_key
  decryption_key = Lockbox::Utils.decode_key(decryption_key, size: 64) if decryption_key

  algorithm ||= "aes-gcm"

  case algorithm
  when "aes-gcm"
    raise ArgumentError, "Missing key" unless key
    @box = AES_GCM.new(key)
  when "xchacha20"
    raise ArgumentError, "Missing key" unless key
    require "rbnacl"
    @box = RbNaCl::AEAD::XChaCha20Poly1305IETF.new(key)
  when "xsalsa20"
    raise ArgumentError, "Missing key" unless key
    require "rbnacl"
    @box = RbNaCl::SecretBoxes::XSalsa20Poly1305.new(key)
  when "hybrid"
    raise ArgumentError, "Missing key" unless encryption_key || decryption_key
    require "rbnacl"
    @encryption_box = RbNaCl::Boxes::Curve25519XSalsa20Poly1305.new(encryption_key.slice(0, 32), encryption_key.slice(32..-1)) if encryption_key
    @decryption_box = RbNaCl::Boxes::Curve25519XSalsa20Poly1305.new(decryption_key.slice(32..-1), decryption_key.slice(0, 32)) if decryption_key
  else
    raise ArgumentError, "Unknown algorithm: #{algorithm}"
  end

  @algorithm = algorithm
  @padding = padding == true ? 16 : padding
  @associated_data = associated_data
end

Instance Method Details

#decrypt(ciphertext, associated_data: NOT_SET) ⇒ Object 



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# File 'lib/lockbox/box.rb', line 60

def decrypt(ciphertext, associated_data: NOT_SET)
  associated_data = @associated_data if associated_data == NOT_SET
  message =
    case @algorithm
    when "hybrid"
      raise ArgumentError, "No decryption key set" unless defined?(@decryption_box)
      raise ArgumentError, "Associated data not supported with this algorithm" if associated_data
      nonce, ciphertext = extract_nonce(@decryption_box, ciphertext)
      @decryption_box.decrypt(nonce, ciphertext)
    when "xsalsa20"
      raise ArgumentError, "Associated data not supported with this algorithm" if associated_data
      nonce, ciphertext = extract_nonce(@box, ciphertext)
      @box.decrypt(nonce, ciphertext)
    else
      nonce, ciphertext = extract_nonce(@box, ciphertext)
      @box.decrypt(nonce, ciphertext, associated_data)
    end
  message = Lockbox.unpad!(message, size: @padding) if @padding
  message
end

#encrypt(message, associated_data: NOT_SET) ⇒ Object 



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# File 'lib/lockbox/box.rb', line 40

def encrypt(message, associated_data: NOT_SET)
  associated_data = @associated_data if associated_data == NOT_SET
  message = Lockbox.pad(message, size: @padding) if @padding
  case @algorithm
  when "hybrid"
    raise ArgumentError, "No encryption key set" unless defined?(@encryption_box)
    raise ArgumentError, "Associated data not supported with this algorithm" if associated_data
    nonce = generate_nonce(@encryption_box)
    ciphertext = @encryption_box.encrypt(nonce, message)
  when "xsalsa20"
    raise ArgumentError, "Associated data not supported with this algorithm" if associated_data
    nonce = generate_nonce(@box)
    ciphertext = @box.encrypt(nonce, message)
  else
    nonce = generate_nonce(@box)
    ciphertext = @box.encrypt(nonce, message, associated_data)
  end
  nonce + ciphertext
end

#inspect ⇒ Object

protect key for xsalsa20, xchacha20, and hybrid



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# File 'lib/lockbox/box.rb', line 82

def inspect
  to_s
end