file-transfer with encryption test

-- By tom2018 5/10/2013 last updated 5/11/2013
-- feel free to modify any part of this program
-- just please send me a PM on the forums!

--encryption found when searching around, author unknown msg me on forums if you own this code and would
--like me to remove it or give you credits

function enc(str, key) -- Function
local tProp = {} -- Make table
for i = 1, str:len() do -- loop for str length
  local val = tonumber((str:byte(i) * tonumber(key) + (12.6 * key)) / 2.8)--Byte str times keyadd 12.6 times key and divide 2.8
  table.insert(tProp, val) -- rest is to return the data
end
return tostring(table.concat(tProp,"|"))
end

function dec(str, key)
local data = {}
for word in string.gmatch(str, "[^|]+") do
  local rdata = ((tonumber(word)*2.8)-(12.6*key))/key
  table.insert(data, math.floor(rdata+0.5))
end
return string.char(unpack(data))
end


--config

side = "top" --modem
rand = false --more secure not yet implemented
btlp = false --not yet implement
stpmsg = "end" --msg that indicates end of file
shtdown = false -- if true will shutdown at end of file transfer
gfb = true -- return current file size and other usefull data
pmsg = "ping" --default ping msg
dc = false --basic encryption method (eta will be wrong)
vsn = 1.4 -- version
cp = true -- keep pinging if failed connection

--code
rednet.open(side)
term.clear()
term.setCursorPos(1,1)
print("tomsfiletranfer "..vsn.."  |")
print("by tom2018           |")
print("---------------------#")
print('Type help for command list')

while true do
ct = false
write("action> ")
p = read()

if p == "help" then
print[[help -cmd list
exit -leave program
id -computer id
files -send file
filer -receive file]]
ct = true
end

if p == "id" then
print(os.getComputerID())
ct = true
end

if p == "filer" then
write("ID> ")
cid = read()
stop = false
cid = cid + 0
write("save as: ")
nami = read()
h = fs.open(nami,"w")
write("ping msg> ")
rednet.send(cid,read())

while stop == false do
icid, pack = rednet.receive(2)
if cp == false then
if icid == nil then
print("no connection established!")
sleep(1.5)
os.reboot()
end
else
if icid == nil then
print("no connection established.")
sleep(1.5)
end
end
if icid == cid then
print("Received "..pack.." Saving to file")

if pack ~= stpmsg then
h.write(pack)
if gfb == true then
print(fs.getSize(nami))
end
else
print("file complete!")
if dc == true then
write("key> ")
keys = read()
h.close()
h = fs.open(nami,'r')
nonen = h.readAll()
h.close()
h = fs.open(nami,'w')
h.write(dec(nonen,keys))
end
if dc == false then
h.close()
end
stop = true
if shtdown == true then
os.shutdown()
else
os.reboot()
end
end

elseif icid ~= nil then
print("Blocked Conection from ID: "..icid)
end
sleep(0)
end

ct = true
end

if p == "files" then
write("file> ")
nami = read()
if dc == true then
write("key> ")
keys = read()
end
h = fs.open(nami,"r")
if dc == false then
wpack = h.readAll()
else
wpack = enc(h.readAll(), keys)
end
wpackt = {}

print("Dividing into Packets may take a while!")
for char in string.gmatch(wpack, ".") do
table.insert(wpackt, char)
sleep(0)
end

if gfb == true then
print("hosting on "..os.getComputerID())
eta = #wpackt * .01
print("Estimated transfer time in seconds")
print(eta)
end

while true do

cid, auth = rednet.receive()
stop = false
c = 1
wpn = #wpackt + 1
if auth == "sup" then
print("Seeding ID:"..cid)
while c < wpn do
rednet.send(cid, wpackt[c])
c = c + 1
sleep(0.01)
end
rednet.send(cid, stpmsg)
print("Seed Complete!")

elseif auth == pmsg then
rednet.send(cid,nami)
end
sleep(0)
end

ct = true
end

if p == "exit" then
print("Thankyou for using Tomsfiletransfer.")
sleep(1.5)
os.reboot()
ct = true
end

if ct == false then
print("Cmd not recongnized.")
end
sleep(0)
end