MATLAB: I am designing SHA-512 algorithm, i am new 2 matlab..i dont know how to perform the padding operation…can anyone help me

sha-512

this is my code

ui=input('enter the username:','s')
pwi=input('enter the password','s')
concate=strcat(ui,pwi)
fprintf('%d',concate) 
str=dec2bin(concate,8)
n=numel(str)
length=mod(896,1024)
a=896-n

now i want to perform the padding operation ,i want 1 followed by 871 zeros. Plz help me

Best Answer

padarray = [ones(1,1), zeros(1,871)];

Why are you trying to fprintf() strings with a %d format? You can do it and it is meaningful in some situations, but I would like to check what benefit you see from doing it.

You should never use "length" as a variable name, as doing so interferes with the MATLAB length() routine.

Are you sure you want 871 zeroes? Shouldn't you be padding "str" to a 1024 length boundary? "str" varies in length; you determined the number of elements in it to be "n", so I am not sure why you want 871 zeroes instead of "enough more than n to reach a 1024 elements boundary". Or if it works on 896 characters at a time, the one would expect a mod() involving 896 as the second argument.

Watch out, your "str" is a 2D matrix not a vector.

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MATLAB: How can i pad 1024 bits of 1 followed by zeros for already existing binary data(k) if the code is

The question does not clearly explain what you are trying to achieve. It would be clearer if you gave exact examples of the data now, and how you want to change it (eg padding, etc).

It seems that you have some existing numeric vector A and wish to pad this with zeros up to a certain length, then you can try:

A = 1:10;
if numel(A)<1024
    A(1024) = 0;
end

A = 1:10;
A = [A,zeros(1,1024-numel(A))]

These will pad the data with zeros up until the index that you provide (e.g. 1024). You might also like to look at padarray .

Note that you use the code ones(1,1), which is simply equivalent to 1. Did you mean to create a vector here, eg ones(1024,1) OR ones(1024-len_n) ?

Also the variable data is a string, which you convert to the character codes using double(data). Is this intentional? Otherwise you can convert the value in the string with num2str, or another string parsing function.

MATLAB: Zero padding or not

   fft(x,1024)

Will automatically zero pad your signal to 1024 points and perform FFT

Best Answer

Related Solutions

MATLAB: How can i pad 1024 bits of 1 followed by zeros for already existing binary data(k) if the code is

MATLAB: Zero padding or not

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