I HAVE A KEY WHICH IS 1*16 MATRIX. HOW CAN I DETERMINE IT'S BIT SIZE?

KEY=[0 0 1 0 3 12 8 7 7 8 12 3 0 1 0 0]

Answer 1

[KSSV]

KEY=[0  0  1  0  3  12  8  7  7  8  12  3  0  1  0  0] ;
a = single(KEY) ;  
iwant = whos('a') 

iwant = struct with fields:
          name: 'a'
          size: [1 16]
         bytes: 64
         class: 'single'
        global: 0
        sparse: 0
       complex: 0
       nesting: [1×1 struct]
    persistent: 0

[sabitri]

Thanks for your support... Will this key prevent brute force attack?

[Walter Roberson]

Will this key prevent brute force attack

NO it will not prevent brute force attack.

There is no known way of preventing brute force attacks.

There are some famous cases where particular encryption challenges were broken by way of contests that organized thousands of computers on the Internet to keep trying sequential possibilities.

You have 4 bits per entry and 16 entries, for a total of 64 bits. It is accepted that the NSA can brute force 64 bit DES encryption keys, using their custom-built hardware.

[sabitri]

Okay...It’s clear to me now..Thanks

Answer 2

[Abderrahim. B]

Hi!

Try this:

KEY = [0  0  1  0  3  12  8  7  7  8  12  3  0  1  0  0] ;
KEY = single(KEY) ;

% WHOS returns a structure
S = whos("KEY")  ;
S.class

ans = 'single'

% Bit is an eighth of a byte
bitSize = S.bytes * 8 

bitSize = 512

Hope this helps

[sabitri]

Thanks a lot. Will this key prevent brute force attack?

Answer 3

[Walter Roberson]

KEY=[0  0  1  0  3  12  8  7  7  8  12  3  0  1  0  0]

KEY = 1×16

0 0 1 0 3 12 8 7 7 8 12 3 0 1 0 0

bits_required_per_entry = max( ceil(log2(KEY)) )

bits_required_per_entry = 4

However the calculation changes if any entry might be negative.

[Walter Roberson]

Also, the calculation changes if any entry might have fractions.