Encryption

-- Scrambler by Just Does Games --



function clr() term.clear() end
function cp(x,y) term.setCursorPos(x,y) end


function encry(ffile, key)
    local file_1 = fs.open(ffile, "r")
    local v_file_lines = 0 -- variable used to store # of lines a file has
    local v_file_letters = 0 -- variable used to store # of letters a file has
    local v_file_current_line_text = "" -- variable used to store line read from the file
    local v_file_current_letter_text -- variable used to store letter read from the file
    local v_file_current_line = 0 -- variable used to show what line the encryptor is on
    local v_file_current_letter = 0 -- variable used to show what letter the encryptor is on
    local v_file_line_table = {} -- table used for converting letters into table later on
    local v_file_line_string = "" -- string used for converting letters into string and copying to second file
    local v_sleep_delay = 6000 -- variable used to tell the system how many times to run the code before using a sleep timer
    local v_sleep_time = .44 -- variable used to show how long to pause the system to avoid 'too long' error
    local v_sleep_variable = 0 -- variable to remember how many times the program has run to use a delay
    local v_key_current = 1 -- variable used to keep track of what key it is on
    local v_tmp = {} -- variable used for anything not important later on in the code and only use temp

    repeat -- finds how many lines and letters there are in the file for later use
        i = file_1.readLine()
        if i ~= nil then
            v_file_lines = v_file_lines + 1
            v_file_letters = v_file_letters + string.len(i)
        end
    until i == nil
    file_1.close()
    local file_1 = fs.open(ffile, "r") -- Reopen file to set selector on 1

    print("File has "..v_file_lines.." lines and "..v_file_letters.." letters") sleep(1)

    v_tmp = {} -- used for converting key into table (string to array)
    for i=1, string.len(key) do
        v_tmp[#v_tmp+1] = string.sub(key,i,i)
    end
    key = v_tmp -- sets key = table
    v_tmp = nil

    if fs.exists(ffile.."_ENCRY") then fs.delete(ffile.."_ENCRY") end
    local file_2 = fs.open(ffile.."_ENCRY", "w") -- opens second file to save encrypted text to

    local running = true
    while running do
        if v_sleep_variable == v_sleep_delay then sleep(v_sleep_time) v_sleep_variable = 0 else v_sleep_variable = v_sleep_variable + 1 end

        local v_file_current_line_text = file_1.readLine() -- reads the next line from the file
        if v_file_current_line_text ~= nil then -- checks to see if there is another line, if not closes the program
            for i=1, string.len(v_file_current_line_text) do -- repeats code below for each letter in the string / line
                v_file_current_letter_text = string.byte(string.sub(v_file_current_line_text,i,i)) -- separates letter from line and converts it into a usable number
                v_file_current_letter_text = v_file_current_letter_text + key[v_key_current] -- adds key value of current key
                if v_key_current == #key then v_key_current = 1 else v_key_current = v_key_current + 1 end -- moves the selected key value by 1 each time
                if v_file_current_letter_text > 255 then -- 255 is the max number of strings in computercraft so we need this number to be lower than this
                    v_file_current_letter_text = v_file_current_letter_text - 255 -- converts it to a number lower than 255
                end
                v_file_line_table[#v_file_line_table+1] = string.char(v_file_current_letter_text) -- places letter into table and converts it into a letter for later use
            end
            v_file_line_string = "" -- resets this variable for new string
            for i=1, #v_file_line_table do
                v_file_line_string = v_file_line_string..v_file_line_table[i] -- creates new string using letters generated
            end
            v_file_line_table = {}
            file_2.writeLine(v_file_line_string) -- writes to second file
        else
            file_1.close()
            file_2.close()
            running = false
        end
    end
end

function decry(ffile, key)
    local file_1 = fs.open(ffile, "r")
    local v_file_lines = 0 -- variable used to store # of lines a file has
    local v_file_letters = 0 -- variable used to store # of letters a file has
    local v_file_current_line_text = "" -- variable used to store line read from the file
    local v_file_current_letter_text -- variable used to store letter read from the file
    local v_file_current_line = 0 -- variable used to show what line the encryptor is on
    local v_file_current_letter = 0 -- variable used to show what letter the encryptor is on
    local v_file_line_table = {} -- table used for converting letters into table later on
    local v_file_line_string = "" -- string used for converting letters into string and copying to second file
    local v_sleep_delay = 6000 -- variable used to tell the system how many times to run the code before using a sleep timer
    local v_sleep_time = .44 -- variable used to show how long to pause the system to avoid 'too long' error
    local v_sleep_variable = 0 -- variable to remember how many times the program has run to use a delay
    local v_key_current = 1 -- variable used to keep track of what key it is on
    local v_tmp = {} -- variable used for anything not important later on in the code and only use temp

    repeat -- finds how many lines and letters there are in the file for later use
        i = file_1.readLine()
        if i ~= nil then
            v_file_lines = v_file_lines + 1
            v_file_letters = v_file_letters + string.len(i)
        end
    until i == nil
    file_1.close()
    local file_1 = fs.open(ffile, "r") -- Reopen file to set selector on 1

    print("File has "..v_file_lines.." lines and "..v_file_letters.." letters") sleep(1)

    v_tmp = {} -- used for converting key into table (string to array)
    for i=1, string.len(key) do
        v_tmp[#v_tmp+1] = string.sub(key,i,i)
    end
    key = v_tmp -- sets key = table
    v_tmp = nil

    if fs.exists(ffile.."_DECRY") then fs.delete(ffile.."_DECRY") end
    local file_2 = fs.open(ffile.."_DECRY", "w") -- opens second file to save decrypted text to

    local running = true
    while running do
        if v_sleep_variable == v_sleep_delay then sleep(v_sleep_time) v_sleep_variable = 0 else v_sleep_variable = v_sleep_variable + 1 end

        local v_file_current_line_text = file_1.readLine() -- reads the next line from the file
        if v_file_current_line_text ~= nil then -- checks to see if there is another line, if not closes the program
            for i=1, string.len(v_file_current_line_text) do -- repeats code below for each letter in the string / line
                v_file_current_letter_text = string.byte(string.sub(v_file_current_line_text,i,i)) -- separates letter from line and converts it into a usable number
                v_file_current_letter_text = v_file_current_letter_text - key[v_key_current] -- adds key value of current key
                if v_key_current == #key then v_key_current = 1 else v_key_current = v_key_current + 1 end -- moves the selected key value by 1 each time
                if v_file_current_letter_text < 1 then -- 255 is the max number of strings in computercraft so we need this number to be lower than this
                    v_file_current_letter_text = v_file_current_letter_text + 255 -- converts it to a number lower than 255
                end
                v_file_line_table[#v_file_line_table+1] = string.char(v_file_current_letter_text) -- places letter into table and converts it into a letter for later use
            end
            v_file_line_string = "" -- resets this variable for new string
            for i=1, #v_file_line_table do
                v_file_line_string = v_file_line_string..v_file_line_table[i] -- creates new string using letters generated
            end
            v_file_line_table = {}
            file_2.writeLine(v_file_line_string) -- writes to second file
        else
            file_1.close()
            file_2.close()
            running = false
        end
    end
end

function generateKey()
    return math.random(10000000, 99999999)
end

m_main = {"Encrypt", "Decrypt", "Exit"}

m_selected = m_main

function run(menu)
    local running = true
    local selected = 1
    clr()
    while running do
        cp(1,1)
        for i=1, #menu do
            if i == selected then
                print("> "..menu[i].." <")
            else
                print("  "..menu[i].."  ")
            end
        end
        a,i = os.pullEvent("key")

        if i == keys.w or i == keys.up then
            if selected ~= 1 then selected = selected - 1 end
        elseif i == keys.s or i == keys.down then
            if selected ~= #menu then selected = selected + 1 end
        elseif i == keys.e or i == keys.enter then
            running = false
        end
    end
    return selected
end

function runtime()
    local running = true
    while running do
    local selected = run(m_selected)
    if m_selected == m_main then
        if selected == #m_selected then
            running = false
        elseif selected == 1 then
            clr() cp(1,1) write("File name: ") name = read() if fs.exists(name) then write("Key: ") key = tonumber(read()) if type(key) == "number" then encry(name,key) print("Encrypted File with key.") sleep(1) print("Press any key to continue") os.pullEvent("key") end end
        elseif selected == 2 then
            clr() cp(1,1) write("File name: ") name = read() if fs.exists(name) then write("Key: ") key = tonumber(read()) if type(key) == "number" then decry(name,key) print("Decrypted File with key.") print("Decryption may not have worked due to an incorrect key. Keep this in mind.") sleep(1) print("Press any key to continue") os.pullEvent("key") end end
        end
    end
    end
    clr() cp(1,1) print("Program created by Just Does Games")
end

runtime()