Doggy OS Bitlocker

-- Encryption and Decryption program for ComputerCraft
-- Encrypts and decrypts every file in the /disk/ directory using a Caesar cipher

local shift = 3 -- Number of positions to shift each character in the Caesar cipher

-- Function to encrypt a string using Caesar cipher
local function encrypt(text, shift)
    local encryptedText = ""
    for i = 1, #text do
        local char = text:sub(i, i)
        local byte = string.byte(char)
        -- Encrypt only printable ASCII characters
        if byte >= 32 and byte <= 126 then
            local newByte = ((byte - 32 + shift) % 95) + 32
            encryptedText = encryptedText .. string.char(newByte)
        else
            encryptedText = encryptedText .. char
        end
    end
    return encryptedText
end

-- Function to decrypt a string using Caesar cipher
local function decrypt(text, shift)
    local decryptedText = ""
    for i = 1, #text do
        local char = text:sub(i, i)
        local byte = string.byte(char)
        -- Decrypt only printable ASCII characters
        if byte >= 32 and byte <= 126 then
            local newByte = ((byte - 32 - shift) % 95) + 32
            decryptedText = decryptedText .. string.char(newByte)
        else
            decryptedText = decryptedText .. char
        end
    end
    return decryptedText
end

-- Function to process a file (encrypt or decrypt based on the action)
local function processFile(filePath, action)
    local file = fs.open(filePath, "r")
    if not file then
        print("Failed to open file: " .. filePath)
        return
    end

    local content = file.readAll()
    file.close()

    local processedContent
    if action == "encrypt" then
        processedContent = encrypt(content, shift)
    elseif action == "decrypt" then
        processedContent = decrypt(content, shift)
    else
        print("Invalid action: " .. action)
        return
    end

    -- Write processed content back to the file
    local processedFile = fs.open(filePath, "w")
    if not processedFile then
        print("Failed to write to file: " .. filePath)
        return
    end

    processedFile.write(processedContent)
    processedFile.close()

    print(action:capitalize() .. ": " .. filePath)
end

-- Function to encrypt or decrypt all files in /disk/
local function processAllFilesInDisk(action)
    local path = "/disk/"

    if not fs.exists(path) then
        print("Path does not exist: " .. path)
        return
    end

    local files = fs.list(path)

    for _, file in ipairs(files) do
        local filePath = fs.combine(path, file)
        if not fs.isDir(filePath) then
            processFile(filePath, action)
        else
            print("Skipping directory: " .. filePath)
        end
    end

    print("All files " .. action .. "ed.")
end

-- Helper function to capitalize the first letter of a string
function string:capitalize()
    return (self:gsub("^%l", string.upper))
end

-- Start the process
local action = "encrypt" -- Change this to "decrypt" to decrypt files
processAllFilesInDisk(action)