FileHider

-- FileHider
-- By KillaVanilla

local args = {...}

if #args == 0 then
    print("FileHider - A file encryption tool")
    print("Usage: "..fs.getName(shell.getRunningProgram()).." [target]")
    return
end

if not fs.exists(args[1]) then
    print("Target file "..args[1].." does not exist!")
    return
end

-- Download the AES API if we don't already have it:

if not fs.exists("AES") then
    local webHandle = http.get("http://pastebin.com/raw.php?i=rCYDnCxn")
    if webHandle then
        local apiData = webHandle.readAll()
        webHandle.close()
        local apiHandle = fs.open("AES", "w")
        apiHandle.write(apiData)
        apiHandle.close()
    else
        print("Could not retrieve AES API!")
        print("Ensure that the HTTP API is enabled.")
        return
    end
end

os.loadAPI("AES")

local function selectParameter(parameterName)
    local x,y = term.getCursorPos()
    local key = {}
    local keyStr = ""
    while true do
        term.setCursorPos(1,y)
        term.clearLine()
        term.setCursorPos(1,y+1)
        term.clearLine()
        term.setCursorPos(1,y)
        print("Please type in the "..parameterName..":")
        write(">")
        keyStr = read()
        if #keyStr > 16 then
            print("Please type in a valid "..parameterName..".")
            os.sleep(1.5)
            term.setCursorPos(1, y+2)
            term.clearLine()
        else
            for i=1, 16 do
                if i > #keyStr then
                    key[i] = 0
                else
                    key[i] = string.byte(keyStr, i, i)
                end
            end
            break
        end
    end
    return key, keyStr
end

local doDecrypt = false
local sX, sY = term.getSize()
local key, keyStr = selectParameter("encryption key")
local iv, ivStr = selectParameter("initalization vector")
local fData = {}
local blocks = {}
local blockNum = 1

local fHandle = fs.open(args[1], "rb")
while true do
    local byte = fHandle.read()
    if byte then
        if byte > 0xFF then
            local t1 = bit.band(byte, 0x000000FF)
            local t2 = bit.brshift(bit.band(byte, 0x0000FF00), 8)
            local t3 = bit.brshift(bit.band(byte, 0x00FF0000), 16)
            local t4 = bit.brshift(bit.band(byte, 0xFF000000), 24)
            table.insert(fData, t1)
            table.insert(fData, t2)
            if t3 ~= 0 then
                table.insert(fData, t3)
            end
            if t4 ~= 0 then
                table.insert(fData, t4)
            end
        else
            table.insert(fData, byte)
        end
    else
        break
    end
end
fHandle.close()

while true do
    term.clear()
    term.setCursorPos(1,1)
    print("Options")
    print("Using key: "..keyStr)
    print("Using IV: "..ivStr)
    print("Size: "..#fData.." bytes, "..math.ceil(#fData/16).." blocks")
    print(string.rep("=", sX))
    print("1 - Encrypt")
    print("2 - Decrypt")
    print("3 - Reselect Key")
    print("4 - Reselect IV")
    print("5 - Exit")
    print("Use your keyboard to make selections.")
    local event, key = os.pullEvent("key")
    term.clear()
    term.setCursorPos(1,1)
    if key == 2 then
        -- Insert the signature:
        table.insert(fData, 1, string.byte("A"))
        table.insert(fData, 1, string.byte("T"))
        table.insert(fData, 1, string.byte("A"))
        table.insert(fData, 1, string.byte("D"))
        break
    elseif key == 3 then
        doDecrypt = true
        break
    elseif key == 4 then
        key, keyStr = selectParameter("encryption key")
    elseif key == 5 then
        iv, ivStr = selectParameter("initalization vector")
    elseif key == 6 then
        return
    end
end

--[[
for i=1, #fData, 16 do
    blocks[blockNum] = {}
    for j=1, 16 do
        blocks[blockNum][j] = fData[i+(j-1)]
    end
    if #blocks[blockNum] < 16 then
        for j=#blocks[blockNum], 16 do
            table.insert(blocks[blockNum], 0)
        end
    end
    blockNum = blockNum+1
end
]]

if not doDecrypt then
    print("Please type in the output file path:")
    write(">")
    local fileName = read()
    print("Encrypting file: "..args[1])
    local bytes = AES.encrypt_bytestream(fData, key, iv)
    --[[
    local x,y = term.getCursorPos()
    for i=1, #blocks do
        term.setCursorPos(x,y)
        term.clearLine()
        term.write("Block: "..i.." of "..#blocks..". ("..math.floor( (i/#blocks)*100 ).."%)")
        blocks[i] = AES.encrypt_block(blocks[i], key)
        os.queueEvent("i_can_fly") -- Credit to MCUniverse, who's primeanac program led to this faster way of yielding.
        os.pullEvent()
    end
    term.setCursorPos(1,y+1)
    ]]
    local fHandle = fs.open(fileName, "wb")
    for byte=1, #bytes do
        fHandle.write(bytes[byte])
    end
    fHandle.close()
    print("Done. Encrypted data saved to:")
    print(fileName)
else
    print("Decrypting file: "..args[1])
    local bytes = AES.decrypt_bytestream(fData, key, iv)
    --[[
    local x,y = term.getCursorPos()
    for i=1, #blocks do
        term.setCursorPos(x,y)
        term.clearLine()
        term.write("Block: "..i.." of "..#blocks..". ("..math.floor( (i/#blocks)*100 ).."%)")
        blocks[i] = AES.decrypt_block(blocks[i], key)
        os.queueEvent("i_can_fly")
        os.pullEvent()
    end
    term.setCursorPos(1,y+1)
    ]]
    if string.char( bytes[1], bytes[2], bytes[3], bytes[4] ) == "DATA" then
        print("Decryption successful.")
        print("Please type in the output file path:")
        write(">")
        local fileName = read()
        local fHandle = fs.open(fileName, "wb")
        for byte=5, #bytes do
            fHandle.write(bytes[byte])
        end
        --[[
        for i=1, #blocks do
            if i==1 then
                for j=5, 16 do
                    fHandle.write(blocks[i][j])
                end
            else
                for j=1, 16 do
                    fHandle.write(blocks[i][j])
                end
            end
        end
        ]]
        fHandle.close()
        print("Data saved to:")
        print(fileName)
    else
        print("Decryption failed.")
    end
end