DES加密的verilog代码

`timescale 1ns / 1ps

//

// Company:

// Engineer:

//

// Create Date: 14:36:27 06/21/2009

// Design Name:

// Module Name: DESencode

// Project Name:

// Target Devices:

// Tool versions:

// Description:

//

// Dependencies:

//

// Revision:

// Revision 0.01 - File Created

// Additional Comments:

//

//

module DESencode(clk,datain,key,code);

input clk; //系统时钟信号

input [1:64]key; //密钥

input [1:64]datain; //要加密的数据

output [1:64]code; //加密后的密码

reg [1:64]code;

reg [4:1]cycnum; //用于记录循环的次数

reg [1:64]LR_reg;

reg [1:64]LR_temp;

wire [1:64]LR;

wire [1:48]bit48;

wire [1:32]bit32;

wire [1:48]sub;

wire [1:32]R_temp;

always@(negedge clk)

begin

cycnum=cycnum+1; //每个时钟周期循环次数加1

LR_temp=LR_reg;

LR_reg[1:32]=LR_temp[33:64]; //右边寄存器的值作为下一次左边寄存器的值

LR_reg[33:64]=LR_temp[1:32]^R_temp; //左边寄存器的值摩尔加置换运算P的结果作为下一次循环右边寄存器的值

end

always@(LR)

begin

LR_reg=LR; //将初始IP变换的值存入左右寄存器中

cycnum=4'h0; //同时循环的次数置0

end

IPexchange M1(.data(datain),.out64(LR)); //初始换位IP

Eexpand M2(.bit32(LR_reg[33:64]),.bit48(bit48)); //选择扩展运算E

subkey M3(.datain(key),.cycnum(cycnum),.key(sub)); //子密钥生成模块

Scompress M4(.bit48(bit48^sub),.bit32(bit32)); //选择压缩运算S

Pexchange M5(.inbit(bit32),.outbit(R_temp)); //置位运算P

IP_inverse_exchange M6(.in64(LR_reg),.cycnum(cycnum),.out64(code)); //逆变换IP_inverse

 

endmodule