A little Xor encoding for more security ^^

[Qousio]

Hello!

I have noticed theres quite a few people asking how to safely encode/protect passwords or text.

My method is far from good, the main purpose is for extra encoding to already encoded text. Although you can use this for just encoding.

Heres an example, I made it simple to understand so anybody can alter/expand it.

$Message = String("Trying to Xor this text")
$Key = 88
$Length = StringLen($Message)
$Array = StringToASCIIArray($Message)

MsgBox(0, "", "The original ASCII is: " & $Array[0])
For $i = 0 To $Length - 1 Step 1
    $Array[$i] = BitXOR($Array[$i], $Key)
Next
MsgBox(0, "", "The encoded ASCII is: " & $Array[0])

$Chr = Chr($Array[0])

MsgBox(0, "", "The encoded char is: " & $Chr)

$Array[0] = BitXOR($Array[0], $Key)

$Chr = Chr($Array[0])

MsgBox(0, "", "The decoded char is: " & $Chr)

For example, you encoded some text with hashing, randomizing, stringexploding, whatever.

Insert the code you got here, and its encoded just a bit more

You can run this script multiple times with different keys, aka:

For $Key to 0 Step -1

And then reverse it the same way, which will result in a decently encoded text.

Here is a working example:

#include <Array.au3>

$Message = String("Insert your text or encoded text here")
$Key = 88
$Length = StringLen($Message)
$Array = StringToASCIIArray($Message)
Dim $Chr[StringLen($Message)]

_ArrayDisplay($Array);This is the original ASCII
For $i = 0 To $Length - 1 Step 1
    $Array[$i] = BitXOR($Array[$i], $Key)
Next
_ArrayDisplay($Array);This is the encoded ASCII

For $i = 0 To $Length - 1 Step 1
    $Chr[$i] = Chr($Array[$i])
Next

_ArrayDisplay($Chr);This is the encoded text

For $i = 0 To $Length - 1 Step 1
    $Chr[$i] = BitXOR($Array[$i], $Key)
Next

_ArrayDisplay($Chr);This is the decoded ASCII

For $i = 0 To $Length - 1 Step 1
    $Chr[$i] = Chr($Chr[$i])
Next

_ArrayDisplay($Chr);This is the decoded text

Edited May 10, 2009 by Qousio

[torels]

Very Nice... Thanks for sharing

[Qousio]

Very Nice... Thanks for sharing

I'm glad you liked it

[torels]

I just have one question now...

how come if I add 4 at the Xor's Result (so BitXOR($Array[$i], $Key)+4) during Encryption and Subtract 4 during decryption the string gets messed up ?

[Qousio]

I just have one question now...

how come if I add 4 at the Xor's Result (so BitXOR($Array[$i], $Key)+4) during Encryption and Subtract 4 during decryption the string gets messed up ?

Because you must only change the key, adding 4 to it would just change the bits. For example:

Xor

0 1 1 1 1 1 1 1

1 0 1 1 1 0 0 1

Would be: 1 1 0 0 0 1 1 0

Adding 4 to it would be 11001010

However, Xor

0 1 1 1 1 1 1 1

(1 0 1 1 1 0 0 1) + 4 = 10111101

Would be 1 1 0 0 0 1 1 0

Hope that answered your question

[UEZ]

_StringEncrypt() is also a simple build-in function (look in the help file).

UEZ

Edited May 11, 2009 by UEZ

[Qousio]

_StringEncrypt() is also a simple build-in function (look in the help file).

UEZ

I know

As I mentioned above: "My method is far from good, the main purpose is for extra encoding to already encoded text. Although you can use this for just encoding."

So basically you Hash it or StringEncrypt and then run this, double encoding, double the fun =P

[torels]

Because you must only change the key, adding 4 to it would just change the bits. For example:

Xor

0 1 1 1 1 1 1 1

1 0 1 1 1 0 0 1

Would be: 1 1 0 0 0 1 1 0

Adding 4 to it would be 11001010

However, Xor

0 1 1 1 1 1 1 1

(1 0 1 1 1 0 0 1) + 4 = 10111101

Would be 1 1 0 0 0 1 1 0

Hope that answered your question

yes thanks

a similar thing was done on a bitmap to encode messages in it I believe

great work anyway