Doggy OS Secure External ecnryption system

-- Define a key for XOR encryption/decryption
local key = 123 -- Change this to a more secure key in practice

-- Function to encrypt/decrypt a string using XOR
local function xorEncryptDecrypt(data, key)
    local result = ""
    for i = 1, #data do
        result = result .. string.char(bit.bxor(data:byte(i), key))
    end
    return result
end

-- Encrypt function
local function encryptDirectory(directory)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local path = fs.combine(directory, file)
        if fs.isDir(path) then
            -- Recursively encrypt directories
            encryptDirectory(path)
        else
            local fileHandle = fs.open(path, "r")
            local content = fileHandle.readAll()
            fileHandle.close()
            local encryptedContent = xorEncryptDecrypt(content, key)
            fileHandle = fs.open(path, "w")
            fileHandle.write(encryptedContent)
            fileHandle.close()
            print("Encrypted: " .. path)
        end
    end
end

-- Decrypt function
local function decryptDirectory(directory)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local path = fs.combine(directory, file)
        if fs.isDir(path) then
            -- Recursively decrypt directories
            decryptDirectory(path)
        else
            local fileHandle = fs.open(path, "r")
            local content = fileHandle.readAll()
            fileHandle.close()
            local decryptedContent = xorEncryptDecrypt(content, key)
            fileHandle = fs.open(path, "w")
            fileHandle.write(decryptedContent)
            fileHandle.close()
            print("Decrypted: " .. path)
        end
    end
end

-- Function to prompt for input and return a trimmed string
local function prompt(promptText)
    write(promptText)
    return read():gsub("^%s*(.-)%s*$", "%1") -- Trim spaces
end

-- Function to check if user credentials are correct
local function checkCredentials(username, password)
    local userFolder = "/disk/users/" .. username
    if not fs.exists(userFolder) then
        print("User folder does not exist: " .. userFolder)
        return false
    end

    local passwordFile = userFolder .. "/password.txt"
    if not fs.exists(passwordFile) then
        print("Password file does not exist: " .. passwordFile)
        return false
    end

    local storedPassword = fs.open(passwordFile, "r").readAll()
    if storedPassword ~= password then
        print("Incorrect password.")
        return false
    end

    return true
end

-- Function to encrypt a disk
local function encryptDisk()
    local username = prompt("Enter username: ")
    local password = prompt("Enter password: ")

    if not checkCredentials(username, password) then
        print("Access denied.")
        return
    end

    -- Check for disk insertion
    local disk = "/disk2/"
    if not fs.exists(disk) then
        print("No disk detected.")
        return
    end

    -- Check for files containing VA11-ILLA or setup
    local function containsRestrictedFiles(directory)
        local files = fs.list(directory)
        for _, file in ipairs(files) do
            local path = fs.combine(directory, file)
            if fs.isDir(path) then
                if containsRestrictedFiles(path) then
                    return true
                end
            elseif file:find("VA11-ILLA") or file:find("setup") then
                return true
            end
        end
        return false
    end

    if containsRestrictedFiles(disk) then
        print("Access denied. Disk contains restricted files.")
        return
    end

    -- Ask if user wants to keep a backup
    local backup = prompt("Do you want to keep a backup of the data? (yes/no): ")
    if backup:lower() == "yes" then
        local backupDir = disk .. "-backup/"
        if fs.exists(backupDir) then
            fs.delete(backupDir) -- Delete if it exists
        end
        fs.copy(disk, backupDir)
        print("Backup created.")
    end

    -- Encrypt the disk
    encryptDirectory(disk)
    print("Disk encrypted.")

    -- Store the encryption key
    local keyFile = fs.open("/disk/users/" .. username .. "/encryption_key.txt", "w")
    keyFile.write(tostring(key))
    keyFile.close()
    print("Encryption key saved.")
end

-- Function to decrypt a disk
local function decryptDisk()
    local username = prompt("Enter username: ")
    local password = prompt("Enter password: ")

    if not checkCredentials(username, password) then
        print("Access denied.")
        return
    end

    -- Check for disk insertion
    local disk = "/disk2/"
    if not fs.exists(disk) then
        print("No disk detected.")
        return
    end

    -- Load the encryption key
    local keyFile = "/disk/users/" .. username .. "/encryption_key.txt"
    if not fs.exists(keyFile) then
        print("No encryption key found.")
        return
    end

    key = tonumber(fs.open(keyFile, "r").readAll())

    -- Decrypt the disk
    decryptDirectory(disk)
    print("Disk decrypted.")

    -- Show directories and files
    local function showFiles(directory, indent)
        indent = indent or ""
        local files = fs.list(directory)
        for _, file in ipairs(files) do
            local path = fs.combine(directory, file)
            if fs.isDir(path) then
                print(indent .. "[" .. file .. "]")
                showFiles(path, indent .. "  ")
            else
                print(indent .. file)
            end
        end
    end

    showFiles(disk)
end

-- Main program loop
while true do
    print("1. Encrypt Disk")
    print("2. Decrypt Disk")
    print("3. Exit")
    local choice = tonumber(read())

    if choice == 1 then
        encryptDisk()
    elseif choice == 2 then
        decryptDisk()
    elseif choice == 3 then
        break
    else
        print("Invalid choice.")
    end
end