encrypting

tfoote, on 22 June 2012 - 12:19 AM said:

How? I don't have anything coded yet… I have looked at the keymapper api but i don't think that is it…

term.clear()
term.setCursorPos(1, 1)
local iEncrypt = nil
local sMessage = nil
local tWords = {}

function NULLencrypt(tWords)  --tried to encrypt as a whole before I realized I could do it during table.insert
for i = 1, #tWords do --function NULLencrypt is not necessary in program code as it is not used
  local sTemp = nil
  for i = 1, string.len(tWords[i]) do
   if i == 1 then
	sTemp = tWords[i]:byte(i)
   else
	sTemp = sTemp .. " " .. tWords[i]:byte(i)
   end
   tWords[i] = sTemp
  end
end
return true
end

function encrypt(string)
local sTemp = nil
for i = 1, string.len(string) do
  if i == 1 then
   sTemp = string:byte(i)
  else
   sTemp = sTemp .. " " .. string:byte(i)
  end
end
return sTemp
end

term.write("Enter message: ")
sMessage = tostring(io.read())

for match in string.gmatch(sMessage, "[^ t]+") do
table.insert( tWords, encrypt(match) .. "b" )
end

for i = 1, #tWords do
print(tWords[i])
end

Enter message: HEY, I JUST MET YOU, AND THIS IS CRAZY. BUT HERE'S MY NUMBER, SO CALL ME MAYBE. --' Now may this song be stuck in your head forever.
72 69 89 44b
73b
74 85 83 84b
77 69 84b
89 79 85 44b
65 78 68b
84 72 73 83b
73 83b
67 82 65 90 89 46b
66 85 84b
72 69 82 69 39 83b
77 89b
78 85 77 66 69 82 44b
83 79b
67 65 76 76b
77 69b
77 65 89 66 69 46b

Bossman201, on 22 June 2012 - 05:00 AM said:

Should be relatively secure, of course if anyone figures out how you're encrypting it, there's a very easy way to decode this.

term.clear()
term.setCursorPos(1, 1)
local iEncrypt = nil
local sMessage = nil
local tWords = {}

function NULLencrypt(tWords)  --tried to encrypt as a whole before I realized I could do it during table.insert
for i = 1, #tWords do --function NULLencrypt is not necessary in program code as it is not used
  local sTemp = nil
  for i = 1, string.len(tWords[i]) do
   if i == 1 then
	sTemp = tWords[i]:byte(i)
   else
	sTemp = sTemp .. " " .. tWords[i]:byte(i)
   end
   tWords[i] = sTemp
  end
end
return true
end

function encrypt(string)
local sTemp = nil
for i = 1, string.len(string) do
  if i == 1 then
   sTemp = string:byte(i)
  else
   sTemp = sTemp .. " " .. string:byte(i)
  end
end
return sTemp
end

term.write("Enter message: ")
sMessage = tostring(io.read())

for match in string.gmatch(sMessage, "[^ t]+") do
table.insert( tWords, encrypt(match) .. "b" )
end

for i = 1, #tWords do
print(tWords[i])
end

The way I would encrypt this would be to add another function that breaks down each "line" of output and multiplies each char code by a user-defined number. This number would then be sent at the very beginning of any rednet message so that the receiving computer can decode the message. Any computers spying will only get a string of huge numbers that won't mean anything. I probably will add this and a decoder to bosschat since I've done the legwork already.

To further screw with spy's, reverse each word before encryption, then reverse the entire table. Then laugh as they flip their tables trying to code a way around your encryption.
(╯°□°)╯︵ ┻━┻

Sample output:

Spoiler

Enter message: HEY, I JUST MET YOU, AND THIS IS CRAZY. BUT HERE'S MY NUMBER, SO CALL ME MAYBE. --' Now may this song be stuck in your head forever.
72 69 89 44b
73b
74 85 83 84b
77 69 84b
89 79 85 44b
65 78 68b
84 72 73 83b
73 83b
67 82 65 90 89 46b
66 85 84b
72 69 82 69 39 83b
77 89b
78 85 77 66 69 82 44b
83 79b
67 65 76 76b
77 69b
77 65 89 66 69 46b

local tWords = {}
for match in string.gmatch(sMessage, "[^ t]+") do
 table.insert( tWords, match .. "b" )
end

In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called a cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key.

Bossman201, on 22 June 2012 - 09:20 AM said:

No, that is just a basic way to prepare a message for encryption. I've left plenty for OP to code on his own. He asked how to break up words which would be

local tWords = {}
for match in string.gmatch(sMessage, "[^ t]+") do
table.insert( tWords, match .. "b" )
end

Technically, it is still encryption because…I can't read it, can you?

In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called a cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key.

-Taken from wikipedia, this is exactly what my code does. The special knowledge or 'key' would be being able to tell that it's just character codes, which a lot of us can tell. So no, you're right, it's not secure. But it is encryption.

tomass1996, on 22 June 2012 - 09:33 AM said:

Bossman201, on 22 June 2012 - 09:20 AM said:

No, that is just a basic way to prepare a message for encryption. I've left plenty for OP to code on his own. He asked how to break up words which would be

local tWords = {}
for match in string.gmatch(sMessage, "[^ t]+") do
table.insert( tWords, match .. "b" )
end

Technically, it is still encryption because…I can't read it, can you?

In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called a cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key.

-Taken from wikipedia, this is exactly what my code does. The special knowledge or 'key' would be being able to tell that it's just character codes, which a lot of us can tell. So no, you're right, it's not secure. But it is encryption.

Your not using an algorithm are you?
And the special knowledge/key would be if you knew the key you need to decrypt it like in symmetrical / asymmetrical encryption or the decryption algorithm.

//EDIT: This is the encryption api from my string utils api, I'm not saying it is extremely secure but it does require you to know the key for encryption/decryption i.e. symmetrical, EncryptionUtils.lua

Lyqyd, on 22 June 2012 - 03:27 PM said:

You don't understand what the word algorithm means. He's using an algorithm. However, that's an obfuscation technique, not an encryption technique. Security through obscurity is no security at all.

kazagistar, on 22 June 2012 - 04:06 PM said:

Again, until we get a bootloader lock, security through obscurity is the only possibility for any computer that someone can access and place a disk drive next to.

MysticT, on 22 June 2012 - 04:42 PM said:

Why? If only you know the key, there's no way to decrypt the message (given you use a good encryption algorithm).

MysticT, on 22 June 2012 - 06:29 PM said:

Well, I wasn't thinking on network encryption, since it would be unnecesary. You can simply send the message to a computer, and no one else can see the message.
If you want to make some network system, with routers and everything, then it could be usefull. Without that is just adding unnecesary overhead.
Also, why would having a bootloader lock be helpfull with this? It would only hide your code, wich is pretty much security through obscurity.

OmegaVest, on 22 June 2012 - 08:08 PM said:

TFoote, use Bossman201's code. As has been said, Obfuscation is best until such time as we can just mod bios.lua. Which is unlikely to happen. But be aware that anytime you just rearrange the text, someone, somehow, will figure out how to put it back right.

tfoote, on 23 June 2012 - 12:05 AM said:

OmegaVest, on 22 June 2012 - 08:08 PM said:

TFoote, use Bossman201's code. As has been said, Obfuscation is best until such time as we can just mod bios.lua. Which is unlikely to happen. But be aware that anytime you just rearrange the text, someone, somehow, will figure out how to put it back right.

Ok.

OmegaVest, on 22 June 2012 - 08:08 PM said:

TFoote, use Bossman201's code.

Bossman201, on 23 June 2012 - 04:15 AM said:

OmegaVest, on 22 June 2012 - 08:08 PM said:

TFoote, use Bossman201's code.

Hell yeah.

But I found a better solution than encryption. Surround routers with blocks, remove privileges to destroy blocks from players. For extra security, add another layer around the router.

local iSeed = math.random()
local tTemp = {}
local tMessage = {}
function encrypt(t)
write your own function
return t
end
math.randomseed( iSeed )
tMessage = encrypt(tTemp)
rednet.send/broadcast([id,] tMessage)

Bossman201, on 23 June 2012 - 04:33 AM said:

EDIT: Although, we learned about encryption, not how to encrypt. So I don't really know how to code it. All I know is obfuscation.