os.loadAPI("rsa")

local function generateKeyPair()
	while true do
		local e = rsa.generateLargePrime()
		write("-")
		sleep(0.1)
		local p = rsa-generatePQ(e)
		write("-")
		sleep(0.1)
		local q = rsa.generatePQ(e)
		write("-")
		sleep(0.1)

		local n = p * q
		local phi = (p - 1) * (q - 1)
		local d = rsa.modinv(e, phi)

		-- 104328 is just a magic number (can be any semi-unique number)
		local encrypted = rsa.modexp(rsa.bigint(104328), e, n)
		local decrypted = rsa.modexp(encrypted, d, n)

		write("+")
		sleep(0.1)
		counter = 0

		if decrypted == rsa.bigint(104328) then
			counter = 0
			return {
				shared = tostring(n),
				public = tostring(e),
			}, {
				shared = tostring(n),
				private = tostring(d),
			}
		end
	end
end

if not fs.exists("/public.key") then
	print("Generating RSA keys, this can take a few minutes.")

	local start = os.clock()

	local publicKey, privateKey = generateKeyPair()

	local file = io.open("./public.key", "w")
	file:write(textutils.serialize(publicKey))
	file:close()
	file = io.open("./private.key", "w")
	file:write(textutils.serialize(privateKey))
	file:close()

	print("Finished!")
end

local f = io.open("/public.key", "r")
local publicKey = textutils.unserialize(f:read("*a"))
f:close()
f = io.open("/private.key", "r")
local privateKey = textutils.unserialize(f:read("*a"))
f:close()

local byteSyze = 8
local bits = 256

local msg = "Heil"

local startTime = os.clock()

local res = rsa.bytesToNumber(rsa.stringToBytes(msg), bits, byteSize)
local encrypted = rsa.crypt(publicKey, res)

print("Took "..os.clock()-startTime.." seconds to encrypt")

print(encrypted)