class RC4

Constants

STATE

Attributes

key[R]

Public Class Methods

new(str) click to toggle source 
# File lib/rc4_cipher.rb, line 5
def initialize(str)
  @i, @j = 0 , 0

  ini_state(str)
end

Public Instance Methods

decrypt!(text)
Alias for: encrypt!
encrypt!(text) click to toggle source 
# File lib/rc4_cipher.rb, line 12
def encrypt!(text)
  n = 0
  while n < text.length
    
    text.setbyte(n,key.next ^ text.getbyte(n))
    n = n.next
  end
  text
end
Also aliased as: decrypt!

Private Instance Methods

ini_state(key) click to toggle source 
# File lib/rc4_cipher.rb, line 29
def ini_state(key)

  @S = STATE.dup

  j = 0
  
  for i in 0..255
    j = (j + @S[i] + key.getbyte(i % key.length)) % 256
    
    @S[i],@S[j] = @S[j],@S[i]
  end

  @key = Enumerator.new do |k|
    while true
      @i = (@i + 1) % 256
      @j = (@j+ @S[@i]) % 256
   
      @S[@i], @S[@j] = @S[@j], @S[@i]
    
      k.yield @S[(@S[@i]+@S[@j])%256]
    end
  end

end