AES.lua

local component = require("component")
local data = component.data

local AES = {}

-- key of AES
AES.key = ""

-- make 128bit AES key
AES.makeKeyAES = function()
  return data.random(16)
end

-- encrypt the line with key,
AES.encrypt = function(line,key)
  if key == nil then
    key = AES.key
  end

  return data.encrypt(line,key,key)
end

-- decrypt the line with key
AES.decrypt= function(line,key)
  if key == nil then
    key = AES.key
  end

  return data.decrypt(line,key,key)
end

--save current key to file
AES.saveKeyAES = function(address,key)
  local file = io.open(address,"w")

  if key == nil then
    key = AES.key
  end

  file:write(AES.key)
  file:close()
end

-- read key value from file
AES.readKeyAES = function(address)
  local file = io.open(address,"r")
  local line = file:read()
  AES.key = line
  file:close()
  return line
end

-- change string to byte arrays, bytes line
AES.string2Bytes = function(line)
  local newBytes = {}
  local newBytesLine = ""
  len = #line

  for i=1, len do
    newBytes[i] = string.byte(line,i)
    newBytesLine = newBytesLine .. " " .. tostring(newBytes[i])
  end

  return newBytes,newBytesLine
end

-- change bytelines to string
AES.byteLine2string = function(bLine)

  local chars = {}
  for char in bLine:gmatch("%w+") do
    table.insert(chars,char)
  end

  local line = ""
  for i,v in ipairs(chars) do
    line = line..string.char(v)
  end

  return line,chars
end

-- encrypt the file with key using AES
-- file will be represented as space and ints
AES.encryptFile = function(oriAdd, encAdd, key)

  if key == nil then
    key = AES.key
  end

  print("read file...")
  local ori = io.open(oriAdd,"r")
  local enc = io.open(encAdd,"w")

  i = 1
  local line = ""
  local lines = {}
  local encLine = ""
  local encByteLine = ""
  while true do
    line = ori:read()

    if line == nil then
      break
    else
      lines[i] = line
      i = i + 1
    end
  end

  local linesNum = #lines
  print("total "..tostring(linesNum).." lines will be encrypted")

  for i,v in ipairs(lines) do
    if v == nil then
      break
    end

    print("encrypting... "..tostring(i).."/"..tostring(linesNum))
    encLine = AES.encrypt(v,key)
    print(encLine)
    _,encByteLine = AES.string2Bytes(encLine)
    print(encByteLine)
    enc:write(encByteLine)
    enc:write("\n")
  end

  ori:close()
  enc:close()
end

-- decrypt file with key using AES
-- decrypted file will be the same as original
AES.decryptFile = function(oriAdd,decAdd,key)
  if key == nil then
     key = AES.key
  end

  print("read File...")
  local ori = io.open(oriAdd,"r")
  local dec = io.open(decAdd,"w")

  i=1
  local line = ""
  local lines = {}
  local charLine = ""
  local decLine = ""

  while true do
    line = ori:read()
    if line == nil then
      break
    else
      lines[i] = line
      i = i+1
    end
  end

  local len = #lines

  print("total "..tostring(len).." lines will be decrypted")

  for i,v in ipairs(lines) do
    if v == nill then
      break
    end

    print("decrypting... "..tostring(i).."/"..tonumber(len))
    charLine = AES.byteLine2string(v)
    print(charLine)
    decLine = AES.decrypt(charLine,key)
    print(decLine)
    dec:write(decLine)
    dec:write("\n")
  end

  ori:close()
  dec:close()

end


return AES