Class: Origami::Encryption::RC4

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

Overview

Pure Ruby implementation of the RC4 symmetric algorithm

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key) ⇒ RC4

Creates and initialises a new RC4 generator using given key



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# File 'lib/origami/encryption.rb', line 610

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 603

def RC4.decrypt(key, data)
    RC4.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 596

def RC4.encrypt(key, data)
    RC4.new(key).encrypt(data)
end

Instance Method Details

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

Encrypt/decrypt data with the RC4 encryption algorithm



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# File 'lib/origami/encryption.rb', line 621

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