Class: Origami::Encryption::ARC4

Inherits:
Object
  • Object
show all
Defined in:
lib/origami/encryption.rb

Overview

Pure Ruby implementation of the aRC4 symmetric algorithm

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key) ⇒ ARC4

Creates and initialises a new aRC4 generator using given key



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# File 'lib/origami/encryption.rb', line 546

def initialize(key)
  if Origami::OPTIONS[:use_openssl]
    @key = key
  else
    @state = init(key)
  end
end

Class Method Details

.decrypt(key, data) ⇒ Object

Decrypts data using the given key



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# File 'lib/origami/encryption.rb', line 539

def ARC4.decrypt(key, data)
  ARC4.new(key).decrypt(data)
end

.encrypt(key, data) ⇒ Object

Encrypts data using the given key



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# File 'lib/origami/encryption.rb', line 532

def ARC4.encrypt(key, data)
  ARC4.new(key).encrypt(data)
end

Instance Method Details

#cipher(data) ⇒ Object Also known as: encrypt, decrypt

Encrypt/decrypt data with the aRC4 encryption algorithm



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# File 'lib/origami/encryption.rb', line 557

def cipher(data)
  return "" if data.empty?

  if Origami::OPTIONS[:use_openssl]
    rc4 = OpenSSL::Cipher::RC4.new.encrypt
    rc4.key_len = @key.length
    rc4.key = @key

    output = rc4.update(data) << rc4.final
  else
    output = ""
    i, j = 0, 0
    data.each_byte do |byte|
      i = i.succ & 0xFF
      j = (j + @state[i]) & 0xFF
      
      @state[i], @state[j] = @state[j], @state[i]
      
      output << (@state[@state[i] + @state[j] & 0xFF] ^ byte).chr
    end
  end

  output
end