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

Question

sabitri 2022-8-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1780020-i-have-a-key-which-is-1-16-matrix-how-can-i-determine-it-s-bit-size

评论： sabitri 2022-8-16

采纳的回答： KSSV

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

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

KSSV 2022-8-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1780020-i-have-a-key-which-is-1-16-matrix-how-can-i-determine-it-s-bit-size#answer_1027155

在 MATLAB Online 中打开

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

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2022-8-16

编辑：Walter Roberson 2022-8-16

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 2022-8-16

Okay...It’s clear to me now..Thanks

请先登录，再进行评论。

Answer 2

Abderrahim. B 2022-8-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1780020-i-have-a-key-which-is-1-16-matrix-how-can-i-determine-it-s-bit-size#answer_1027160

编辑：Abderrahim. B 2022-8-16

在 MATLAB Online 中打开

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

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

sabitri 2022-8-16

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

请先登录，再进行评论。

Answer 3

Walter Roberson 2022-8-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1780020-i-have-a-key-which-is-1-16-matrix-how-can-i-determine-it-s-bit-size#answer_1027185

在 MATLAB Online 中打开

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