sha256.v

安全散列函数的VERILOG实现

                        'd14:
                                begin
                                        W14 <= text_i;
                                        Wt <= text_i;
                                        
                                        H <= G;
                                        G <= F;
                                        F <= E;
                                        E <= next_E;
                                        D <= C;
                                        C <= B;
                                        B <= A;
                                        A <= next_A;
                                                
                                        round <= round_plus_1;
                                end
                        'd15:
                                begin
                                        Wt <= text_i;
                                        
                                        H <= G;
                                        G <= F;
                                        F <= E;
                                        E <= next_E;
                                        D <= C;
                                        C <= B;
                                        B <= A;
                                        A <= next_A;
                                                
                                        round <= round_plus_1;
                                end
                        'd16,
                        'd17,
                        'd18,
                        'd19,
                        'd20,
                        'd21,
                        'd22,
                        'd23,
                        'd24,
                        'd25,
                        'd26,
                        'd27,
                        'd28,
                        'd29,
                        'd30,
                        'd31,
                        'd32,
                        'd33,
                        'd34,
                        'd35,
                        'd36,
                        'd37,
                        'd38,
                        'd39,
                        'd40,
                        'd41,
                        'd42,
                        'd43,
                        'd44,
                        'd45,
                        'd46,
                        'd47,
                        'd48,
                        'd49,
                        'd50,
                        'd51,
                        'd52,
                        'd53,
                        'd54,
                        'd55,
                        'd56,
                        'd57,
                        'd58,
                        'd59,
                        'd60,
                        'd61,
                        'd62,
                        'd63:
                                begin
                                        W0  <= W1;
                                        W1  <= W2;
                                        W2  <= W3;
                                        W3  <= W4;
                                        W4  <= W5;
                                        W5  <= W6;
                                        W6  <= W7;
                                        W7  <= W8;
                                        W8  <= W9;
                                        W9  <= W10;
                                        W10 <= W11;
                                        W11 <= W12;
                                        W12 <= W13;
                                        W13 <= W14;
                                        W14 <= Wt;
                                        Wt  <= next_Wt;
                                        
                                        H <= G;
                                        G <= F;
                                        F <= E;
                                        E <= next_E;
                                        D <= C;
                                        C <= B;
                                        B <= A;
                                        A <= next_A;
                                                
                                        round <= round_plus_1;
                                end
                        'd64:
                                begin
                                        A <= next_A + H0;
                                        B <= A + H1;
                                        C <= B + H2;
                                        D <= C + H3;
                                        E <= next_E + H4;
                                        F <= E + H5;
                                        G <= F + H6;
                                        H <= G + H7;
                                        round <= 'd0;
                                        busy <= 'b0;
                                end
                        default:
                                begin
                                        round <= 'd0;
                                        busy <= 'b0;
                                end
                        endcase
                end     
        end 
        
        
        //------------------------------------------------------------------    
        // Kt generator
        //------------------------------------------------------------------    
        always @ (posedge clk_i)
        begin
                if (rst_i)
                begin
                        Kt <= 'b0;
                end
                else
                begin
                        case (round)
                                'd00:   Kt <= `K00;
                                'd01:   Kt <= `K01;
                                'd02:   Kt <= `K02;
                                'd03:   Kt <= `K03;
                                'd04:   Kt <= `K04;
                                'd05:   Kt <= `K05;
                                'd06:   Kt <= `K06;
                                'd07:   Kt <= `K07;
                                'd08:   Kt <= `K08;
                                'd09:   Kt <= `K09;
                                'd10:   Kt <= `K10;
                                'd11:   Kt <= `K11;
                                'd12:   Kt <= `K12;
                                'd13:   Kt <= `K13;
                                'd14:   Kt <= `K14;
                                'd15:   Kt <= `K15;
                                'd16:   Kt <= `K16;
                                'd17:   Kt <= `K17;
                                'd18:   Kt <= `K18;
                                'd19:   Kt <= `K19;
                                'd20:   Kt <= `K20;
                                'd21:   Kt <= `K21;
                                'd22:   Kt <= `K22;
                                'd23:   Kt <= `K23;
                                'd24:   Kt <= `K24;
                                'd25:   Kt <= `K25;
                                'd26:   Kt <= `K26;
                                'd27:   Kt <= `K27;
                                'd28:   Kt <= `K28;
                                'd29:   Kt <= `K29;
                                'd30:   Kt <= `K30;
                                'd31:   Kt <= `K31;
                                'd32:   Kt <= `K32;
                                'd33:   Kt <= `K33;
                                'd34:   Kt <= `K34;
                                'd35:   Kt <= `K35;
                                'd36:   Kt <= `K36;
                                'd37:   Kt <= `K37;
                                'd38:   Kt <= `K38;
                                'd39:   Kt <= `K39;
                                'd40:   Kt <= `K40;
                                'd41:   Kt <= `K41;
                                'd42:   Kt <= `K42;
                                'd43:   Kt <= `K43;
                                'd44:   Kt <= `K44;
                                'd45:   Kt <= `K45;
                                'd46:   Kt <= `K46;
                                'd47:   Kt <= `K47;
                                'd48:   Kt <= `K48;
                                'd49:   Kt <= `K49;
                                'd50:   Kt <= `K50;
                                'd51:   Kt <= `K51;
                                'd52:   Kt <= `K52;
                                'd53:   Kt <= `K53;
                                'd54:   Kt <= `K54;
                                'd55:   Kt <= `K55;
                                'd56:   Kt <= `K56;
                                'd57:   Kt <= `K57;
                                'd58:   Kt <= `K58;
                                'd59:   Kt <= `K59;
                                'd60:   Kt <= `K60;
                                'd61:   Kt <= `K61;
                                'd62:   Kt <= `K62;
                                'd63:   Kt <= `K63;
                                default:Kt <= 'd0;
                        endcase
                end
        end

        //------------------------------------------------------------------    
        // read result 
        //------------------------------------------------------------------    
        always @ (posedge clk_i)
        begin
                if (rst_i)
                begin
                        text_o <= 'b0;
                        read_counter <= 'b0;
                end
                else
                begin
                        if (cmd[0])
                        begin
                                read_counter <= 'd7;    // sha-256      256/32=8
                        end
                        else
                        begin
                        if (~busy)
                        begin
                                case (read_counter)
                                        'd7:    text_o <= SHA256_result[8*32-1:7*32];
                                        'd6:    text_o <= SHA256_result[7*32-1:6*32];
                                        'd5:    text_o <= SHA256_result[6*32-1:5*32];
                                        'd4:    text_o <= SHA256_result[5*32-1:4*32];
                                        'd3:    text_o <= SHA256_result[4*32-1:3*32];
                                        'd2:    text_o <= SHA256_result[3*32-1:2*32];
                                        'd1:    text_o <= SHA256_result[2*32-1:1*32];
                                        'd0:    text_o <= SHA256_result[1*32-1:0*32];
                                        default:text_o <= 'b0;
                                endcase
                                if (|read_counter)
                                        read_counter <= read_counter - 'd1;
                        end
                        else
                        begin
                                text_o <= 'b0;
                        end
                        end
                end
        end
        
endmodule