metasploit-gs/lib/msf/core/encoding/xor.rb

module Msf
module Encoding

###
#
# This class provides basic XOR encoding facilities and is used
# by XOR encoders.
#
###
class Xor

	#
	# Encodes a block using XOR.
	#
	def Xor.encode_block(key, block, block_size = 4, block_pack = 'V')
		offset = 0
		oblock = ''

		while (offset < block.length)
			cblock  = block[offset, block_size].unpack(block_pack)[0]
			cblock ^= key
			oblock += [ cblock ].pack(block_pack)
		end
		
		return oblock
	end

end

end end