simple brute force code to crack AES

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polaris - 02 Apr 2008 19:31 GMT

hi
I should write a code to break AES encryption. I have the key in file
but its not complete so i have to guess the missing right most 16-
bits
out of 128-bits. I don't know how to treat the key at the level of
bit
where i get it as SecretKey. This is my code:

ObjectInputStream in = new ObjectInputStream(new
FileInputStream("SecretKey.ser"));
SecretKey key = (SecretKey)in.readObject();
byte[] raw = key.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

how can i make a for loop to move over all possible key values.

please help

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Roedy Green - 02 Apr 2008 21:39 GMT

On Wed, 2 Apr 2008 11:31:01 -0700 (PDT), polaris
<smarto59@hotmail.com> wrote, quoted or indirectly quoted someone who
said :

>how can i make a for loop to move over all possible key values.

see http://mindprod.com/jgloss/combination.html

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Arne Vajhøj - 09 Apr 2008 02:43 GMT

> I should write a code to break AES encryption. I have the key in file
> but its not complete so i have to guess the missing right most 16-
[quoted text clipped - 10 lines]
>
> how can i make a for loop to move over all possible key values.

Try:

for(int i = 0; i < 256; i++) {
raw[14] = (byte)i;
for(int j = 0; j < 256; j++) {
raw[15] = (byte)j;
// test raw
}
}

assuming you really have the first 112 bits and only miss the
last 16 bit of raw.

Arne

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simple brute force code to crack AES

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