%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Copyright: 2010 Integrated Sytems Laboratory, ETH Zurich
%%            http://www.iis.ee.ethz.ch/~sha3
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function [a, c] = step_part(a, c)
a(1:4)=subcrumb(a(1:4));
% a(5:8)=subcrumb(a(5:8));

t=subcrumb([a(6) a(7) a(8) a(5)]);
a(5) = t(4);
a(6) = t(1);
a(7) = t(2);
a(8) = t(3);

for k=1:4
    [a(k), a(k+4)]=mixword(a(k), a(k+4));
end
[cns, c]=genconstant(c);
a=addconstant(a, cns);
end