SHA3_hex.m

%
% SHA3_text function
%
function HASH = SHA3_hex(s_input, HASH_type, HASH_len)
    %
    % parameters and message
    %
    % HASH_type
    % HASH_len
    % s_input
    %
    d  = 0;
    dd = 0;
    subtype = '';
    if strcmp(HASH_type, 'SHA3-224') == 1
        d = 224; % the fixed langth of the massage digest size
        dd = d;  % bit number
        subtype = 'HASH';
    elseif strcmp(HASH_type, 'SHA3-256') == 1
        d = 256; % massage digest size
        dd = d;
        subtype = 'HASH';
    elseif strcmp(HASH_type, 'SHA3-384') == 1
        d = 384; % massage digest size
        dd = d;
        subtype = 'HASH';
    elseif strcmp(HASH_type, 'SHA3-512') == 1
        d = 512; % massage digest size
        dd = d;
        subtype = 'HASH';
    elseif strcmp(HASH_type, 'SHAKE128') == 1
        d = 128;
        dd = HASH_len;
        subtype = 'XOF';
    elseif strcmp(HASH_type, 'SHAKE256') == 1
        d = 256;
        dd = HASH_len;
        subtype = 'XOF';
    end
    %
    % fixed coefficient
    %
    b = 1600;  % total bits = 25*25*64 = 1600
    nr = 24;   % number of rounds
    c = 2 * d; % capacity
    r = b - c; % for every r-bit a section
    w = b / 25;   % depth of the state array = 1600 / 25 = 64
    LL = log2(w); % use LL to avoid naming collision in just L
    %
    % Lk: , k: 
    [Lk, k] = input_string_2_L_array_hex(s_input, d, subtype);
    for ix = 0 : 4
        for iy = 0 : 4
            % fprintf('L(%d, %d) = %s\n',ix, iy, Lk(ix + 1, iy + 1, :));
        end
    end
    %
    % initial state array
    %
    Lp = char();
    for iy = 0 : 4
        for ix = 0 : 4
            Lp(ix + 1, iy + 1, :) = '0000000000000000';
        end
    end
    %
    % sponge construction
    %
    for ik = 1 : k
        L = Lk(:, :, :, ik);
        for iy = 0 : 4
            for ix = 0 : 4
                % L(ix + 1, iy + 1, :) = bitxor_64(L(ix + 1, iy + 1, :), Lp(ix + 1, iy + 1, :));
            end
        end
        L = f_function(L);
        Lp = L;
    end
    %
    % final state
    %
    % fprintf('final state \n');
    for ix = 0 : 4
        for iy = 0 : 4
            % fprintf('L(%d, %d) = %s\n',ix, iy, L(ix + 1, iy + 1, :, 1));
        end
    end
    %
    % generation of the HASH value
    %
    HASH = char();
    d8 = dd / 8;
    counter = 0;
    if strcmp(subtype, 'HASH') == 1
    %     HASH = char();
    %     d8 = dd / 8;
    %     counter = 0;
        for iy = 0 : 4
            for ix = 0 : 4
                for iz = 0 : 7
                    counter = counter + 1;
                    if counter <= d8
                        HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz - 1, 1));
                        HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz    , 1));
                    end
                end
            end
        end
    elseif strcmp(subtype, 'XOF') == 1
        HASH = char();
        d8 = floor(dd / 8); % 
        r8 = r / 8;         % 
        counter = 0;
        for iy = 0 : 4
            for ix = 0 : 4
                for iz = 0 : 7
                    counter = counter + 1;
                    if counter <= r8
                        HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz - 1, 1));
                        HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz    , 1));
                    end
                end
            end
        end
        while length(HASH) < d8 * 2
            L = f_function(L);
            counter = 0;
            for iy = 0 : 4
                for ix = 0 : 4
                    for iz = 0 : 7
                        counter = counter + 1;
                        if counter <= r8
                            HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz - 1, 1));
                            HASH = strcat(HASH , L(ix + 1, iy + 1, 16 - 2*iz    , 1));
                        end
                    end
                end
            end
        end % end while
        HASH = HASH(1 : d8 * 2);
    end
    HASH = lower(HASH);
return
%