Syscrypt_decrypt

--[[
    MIT License

    Copyright © 2016 Chickenbreadlp

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
]]

local function unfoldkey(keyinput)
 math.randomseed(tonumber(keyinput, 36))
 y = {}
 z = {}
 for i=1, 16 do
  y[i] = math.random(0, 0xFF)
  z[i] = math.random(0, 0xFF)
 end
 math.randomseed(math.random())
 return y, z
end

local function encrypt(dir)
 if dir == nil then dir = "" end
 local ListFiles = fs.list(dir)
 for _, file in ipairs(ListFiles) do
  if fs.isDir(dir..file) then
   if file ~= "rom" and file ~= ".syscrypt" and file ~= ".SyscryptShut" then
    encrypt(dir.."/"..file.."/")
   end
  else
   if file == "startup" then
   else
    local prog = fs.open(dir.."/"..file, "rb")
    local progData = {}
    local progbyte = prog.read()
    repeat
     table.insert(progData, progbyte)
     progbyte = prog.read()
    until progbyte == nil
    prog.close()
    progData = ccaes.encrypt_bytestream(progData, y, z)
    local prog = fs.open(dir.."/"..file, "wb")
    for i=1, #progData do
     prog.write(progData[i])
    end
    prog.close()
    sleep(0.01)
   end
  end
 end
end

local y = {}
local z = {}

if fs.exists("/User/.SyscryptSetup") then
 fs.delete("/User/.SyscryptSetup")
end

if fs.exists("/User/.SyscryptShut") then
 fs.delete("/User/.SyscryptShut")
end

if syscrypt_alredydecrypt == true then
 shell.run("/.syscrypt/boot")
elseif fs.exists("/.syscrypt/.reboot") then

 local file = fs.open("/.syscrypt/.reboot", "r")
 syscrypt_keyhash = file.readLine()
 file.close()

 os.loadAPI("/.syscrypt/hash")
 os.loadAPI("/.syscrypt/ccaes")

 local oshut = os.shutdown
 os.shutdown = function()
  fs.delete("/.syscrypt/.reboot")
  if fs.exists("/ReboOSt") and login == true then
   if fs.exists("/User/.SyscryptShut/..meta") then
    fs.delete("/User/.SyscryptShut/..meta")
   end
   fs.makeDir("/User/.SyscryptShut/")
   local file = fs.open("/User/.SyscryptShut/..meta", "w")
   if admin then
    file.writeLine(hash.sha256(UserPass.."admin"))
   else
    file.writeLine(hash.sha256(UserPass.."stand"))
   end
   file.close()
   UserName = ".SyscryptShut"
  end
  y, z = unfoldkey(syscrypt_keyhash)
  encrypt()
  oshut()
 end
 syscrypt_alredydecrypt = true
 term.clear()
 term.setCursorPos(1,1)
 if fs.exists("/.syscrypt/boot") then
  shell.run("/.syscrypt/boot")
 else
  shell.run("shell")
 end
else

os.loadAPI("/.syscrypt/hash")
os.loadAPI("/.syscrypt/ccaes")
term.setBackgroundColor(colors.black)
term.setTextColor(colors.white)
term.clear()
local textXI = (52 - string.len("This Computer has been protected with Syscrypt")) / 2
local textXV = (52 - string.len("To decrypt, enter in your password below")) / 2
term.setCursorPos(textXI, 3)
print("This Computer has been protected with Syscrypt")
term.setCursorPos(textXV, 4)
print("To decrypt, enter in your password below")
while true do
 term.setCursorPos(1,7)
 term.clearLine()
 term.setCursorPos(1,8)
 term.clearLine()
 term.setCursorPos(1,7)
 write("Password: ")
 local oldpe = os.pullEvent()
 os.pullEvent = os.pullEventRaw
 syscrypt_keyhash = hash.sha256(read("*"))
 shell.run("/.syscrypt/reference_key")
 if hash.sha256(syscrypt_keyhash) == syscrypt_key then
  y, z = unfoldkey(syscrypt_keyhash)

  local function decrypt(dir)
   if dir == nil then dir = "" end
   local ListFiles = fs.list(dir)
   for _, file in ipairs(ListFiles) do
    if fs.isDir(dir..file) then
     if file ~= "rom" and file ~= ".syscrypt" then
      term.setTextColor(colors.lime)
      decrypt(dir.."/"..file.."/")
     end
    else
     if file == "startup" then
     else
      local prog = fs.open(dir.."/"..file, "rb")
      local progData = {}
      local progbyte = prog.read()
      repeat
      table.insert(progData, progbyte)
      progbyte = prog.read()
      until progbyte == nil
      prog.close()
      progData = ccaes.decrypt_bytestream(progData, y, z)
      local prog = fs.open(dir.."/"..file, "wb")
      for i=1, #progData do
       prog.write(progData[i])
      end
      prog.close()
      sleep(0.01)
     end
    end
   end
  end

  decrypt()

  local file = fs.open("/.syscrypt/.reboot", "w")
  file.writeLine(syscrypt_keyhash)
  file.close()

  local oshut = os.shutdown
  os.shutdown = function()
   fs.delete("/.syscrypt/.reboot")
   if fs.exists("/ReboOSt") and login == true then
    if fs.exists("/User/.SyscryptShut/..meta") then
     fs.delete("/User/.SyscryptShut/..meta")
    end
    fs.makeDir("/User/.SyscryptShut/")
    local file = fs.open("/User/.SyscryptShut/..meta", "w")
    if admin then
     file.writeLine(hash.sha256(UserPass.."admin"))
    else
     file.writeLine(hash.sha256(UserPass.."stand"))
    end
    file.close()
    UserName = ".SyscryptShut"
   end
   y, z = unfoldkey(syscrypt_keyhash)
   encrypt()
   oshut()
  end

  syscrypt_alredydecrypt = true
  term.clear()
  term.setCursorPos(1,1)
  if fs.exists("/.syscrypt/boot") then
   shell.run("/.syscrypt/boot")
  else
   shell.run("shell")
  end
  break
 else
  printError("Wrong Password!")
  sleep(2)
 end
end
end