116 lines
2.1 KiB
Ruby
116 lines
2.1 KiB
Ruby
require "rmagick"
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require "digest"
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class ImageUtils
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@@magickImg = nil
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@@password = ""
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@@message = ""
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@@hash = nil
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@@width = 0
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@@height = 0
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@@pixel_arr = []
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def initialize(pass, msg, uri)
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@@password = pass
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@@message = msg
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@@salt = 0
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@@magickImg = Magick::Image.read(uri).first
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@@width = @@magickImg.columns
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@@height = @@magickImg.rows
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@@pixel_arr = @@magickImg.get_pixels(0, 0, @@width, @@height)
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if msg.length > 1024 then
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puts "Maximum length exceeded. Exiting."
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exit
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end
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self.generateHash
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end
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def getPixel(x, y)
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loc = (y*@@width) + x
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return @@pixel_arr[loc]
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end
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def getSalt
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for x in 0..@@width-1
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for y in 0..@@height-1
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pix = self.getPixel(x, y)
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@@salt = @@salt + (pix.red/512)
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@@salt = @@salt + (pix.green/512)
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@@salt = @@salt + (pix.blue/512)
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end
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end
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h = Digest::SHA512.hexdigest(@@salt.to_s(16))
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return h
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end
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def generateHash
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pass_h = Digest::SHA512.hexdigest(@@password)
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@@hash = Digest::SHA512.hexdigest(pass_h + @@salt.to_s)
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end
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def generateLookupTable
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tbl = []
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hash_bits = @@pixelImg.getBits(@@hash)
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msg_bits = @@pixelImg.getBits(@@message)
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# gross, but pad in the 24 bits that will become the msg length
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# and padding bits...
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msg_bits = msg_bits << 24
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while msg_bits > 0 do
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loc = nil
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loop do
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x = (hash_bits.to_i % @@pixelImg.getSize[:width])
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y = (hash_bits.to_i % @@pixelImg.getSize[:height])
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loc = {"x": x, "y": y}
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break if !tbl.include?(loc)
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hash_bits = hash_bits >> 1
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if hash_bits <= 0 then
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puts
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puts "wow too much data"
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puts "leftover bits: " + msg_bits.to_s(36)
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exit
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end
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end
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hash_bits = hash_bits >> 1
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tbl.push(loc)
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msg_bits = msg_bits >> 6
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end
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return tbl
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end
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def getBits(o)
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msg_bytes = o.unpack("c*")
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msg_bits = 0
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for b in msg_bytes
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msg_bits = (msg_bits << 8) | b
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end
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return msg_bits
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end
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end
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