Mercurial > hg > ltpda
diff m-toolbox/classes/+utils/@prog/hash.m @ 0:f0afece42f48
Import.
author | Daniele Nicolodi <nicolodi@science.unitn.it> |
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date | Wed, 23 Nov 2011 19:22:13 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m-toolbox/classes/+utils/@prog/hash.m Wed Nov 23 19:22:13 2011 +0100 @@ -0,0 +1,94 @@ +function h = hash(inp,meth) +% HASH - Convert an input variable into a message digest. +% +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% +% HASH - Convert an input variable into a message digest using any of +% several common hash algorithms +% +% USAGE: h = hash(inp,'meth') +% +% inp = input variable, of any of the following classes: +% char, uint8, logical, double, single, int8, uint8, +% int16, uint16, int32, uint32, int64, uint64 +% h = hash digest output, in hexadecimal notation +% meth = hash algorithm, which is one of the following: +% MD2, MD5, SHA-1, SHA-256, SHA-384, or SHA-512 +% +% NOTES: (1) If the input is a string or uint8 variable, it is hashed +% as usual for a byte stream. Other classes are converted into +% their byte-stream values. In other words, the hash of the +% following will be identical: +% 'abc' +% uint8('abc') +% char([97 98 99]) +% The hash of the follwing will be different from the above, +% because class "double" uses eight byte elements: +% double('abc') +% [97 98 99] +% You can avoid this issue by making sure that your inputs +% are strings or uint8 arrays. +% (2) The name of the hash algorithm may be specified in lowercase +% and/or without the hyphen, if desired. For example, +% h=hash('my text to hash','sha256'); +% (3) Carefully tested, but no warranty. Use at your own risk. +% (4) Michael Kleder, Nov 2005 +% (5) This is a direct copy of the code from Michael Kleder. Only +% the function name was changed to bring it in line with the +% LTPDA naming convention. (M Hewitson 15-09-07) +% +% EXAMPLE: +% +% algs={'MD2','MD5','SHA-1','SHA-256','SHA-384','SHA-512'}; +% for n=1:6 +% h=hash('my sample text',algs{n}); +% disp([algs{n} ' (' num2str(length(h)*4) ' bits):']) +% disp(h) +% end +% +% NOTE: Original taken from MATHWORKS file exchange. +% Author: Michael Kleder, Nov 2005 +% http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=8944&objectType=file +% +% $Id: hash.m,v 1.1 2008/06/18 13:35:11 hewitson Exp $ +% +% + +inp=inp(:); +% convert strings and logicals into uint8 format +if ischar(inp) || islogical(inp) + inp=uint8(inp); +else % convert everything else into uint8 format without loss of data + inp=typecast(inp,'uint8'); +end + +% verify hash method, with some syntactical forgiveness: +meth=upper(meth); +switch meth + case 'SHA1' + meth='SHA-1'; + case 'SHA256' + meth='SHA-256'; + case 'SHA384' + meth='SHA-384'; + case 'SHA512' + meth='SHA-512'; + otherwise +end +algs={'MD2','MD5','SHA-1','SHA-256','SHA-384','SHA-512'}; +if isempty(strmatch(meth,algs,'exact')) + error(['Hash algorithm must be ' ... + 'MD2, MD5, SHA-1, SHA-256, SHA-384, or SHA-512']); +end + +% create hash +x=java.security.MessageDigest.getInstance(meth); +x.update(inp); +h=typecast(x.digest,'uint8'); +h=dec2hex(h)'; +if(size(h,1))==1 % remote possibility: all hash bytes < 128, so pad: + h=[repmat('0',[1 size(h,2)]);h]; +end +h=lower(h(:)'); +clear x +return \ No newline at end of file