Daniel@0: function h = hash(inp,meth)
Daniel@0: % HASH - Convert an input variable into a message digest using any of
Daniel@0: %        several common hash algorithms
Daniel@0: %
Daniel@0: % USAGE: h = hash(inp,'meth')
Daniel@0: %
Daniel@0: % inp  = input variable, of any of the following classes:
Daniel@0: %        char, uint8, logical, double, single, int8, uint8,
Daniel@0: %        int16, uint16, int32, uint32, int64, uint64
Daniel@0: % h    = hash digest output, in hexadecimal notation
Daniel@0: % meth = hash algorithm, which is one of the following:
Daniel@0: %        MD2, MD5, SHA-1, SHA-256, SHA-384, or SHA-512 
Daniel@0: %
Daniel@0: % NOTES: (1) If the input is a string or uint8 variable, it is hashed
Daniel@0: %            as usual for a byte stream. Other classes are converted into
Daniel@0: %            their byte-stream values. In other words, the hash of the
Daniel@0: %            following will be identical:
Daniel@0: %                     'abc'
Daniel@0: %                     uint8('abc')
Daniel@0: %                     char([97 98 99])
Daniel@0: %            The hash of the follwing will be different from the above,
Daniel@0: %            because class "double" uses eight byte elements:
Daniel@0: %                     double('abc')
Daniel@0: %                     [97 98 99]
Daniel@0: %            You can avoid this issue by making sure that your inputs
Daniel@0: %            are strings or uint8 arrays.
Daniel@0: %        (2) The name of the hash algorithm may be specified in lowercase
Daniel@0: %            and/or without the hyphen, if desired. For example,
Daniel@0: %            h=hash('my text to hash','sha256');
Daniel@0: %        (3) Carefully tested, but no warranty. Use at your own risk.
Daniel@0: %        (4) Michael Kleder, Nov 2005
Daniel@0: %
Daniel@0: % EXAMPLE:
Daniel@0: %
Daniel@0: % algs={'MD2','MD5','SHA-1','SHA-256','SHA-384','SHA-512'};
Daniel@0: % for n=1:6
Daniel@0: %     h=hash('my sample text',algs{n});
Daniel@0: %     disp([algs{n} ' (' num2str(length(h)*4) ' bits):'])
Daniel@0: %     disp(h)
Daniel@0: % end
Daniel@0: 
Daniel@0: inp=inp(:);
Daniel@0: % convert strings and logicals into uint8 format
Daniel@0: if ischar(inp) || islogical(inp)
Daniel@0:     inp=uint8(inp);
Daniel@0: else % convert everything else into uint8 format without loss of data
Daniel@0:     inp=typecast(inp,'uint8');
Daniel@0: end
Daniel@0: 
Daniel@0: % verify hash method, with some syntactical forgiveness:
Daniel@0: meth=upper(meth);
Daniel@0: switch meth
Daniel@0:     case 'SHA1'
Daniel@0:         meth='SHA-1';
Daniel@0:     case 'SHA256'
Daniel@0:         meth='SHA-256';
Daniel@0:     case 'SHA384'
Daniel@0:         meth='SHA-384';
Daniel@0:     case 'SHA512'
Daniel@0:         meth='SHA-512';
Daniel@0:     otherwise
Daniel@0: end
Daniel@0: algs={'MD2','MD5','SHA-1','SHA-256','SHA-384','SHA-512'};
Daniel@0: if isempty(strmatch(meth,algs,'exact'))
Daniel@0:     error(['Hash algorithm must be ' ...
Daniel@0:         'MD2, MD5, SHA-1, SHA-256, SHA-384, or SHA-512']);
Daniel@0: end
Daniel@0: 
Daniel@0: % create hash
Daniel@0: x=java.security.MessageDigest.getInstance(meth);
Daniel@0: x.update(inp);
Daniel@0: h=typecast(x.digest,'uint8');
Daniel@0: h=dec2hex(h)';
Daniel@0: if(size(h,1))==1 % remote possibility: all hash bytes < 128, so pad:
Daniel@0:     h=[repmat('0',[1 size(h,2)]);h];
Daniel@0: end
Daniel@0: h=lower(h(:)');
Daniel@0: clear x
Daniel@0: return