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AES_Decrypt.v
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AES_Decrypt.v
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module AES_Decrypt#(parameter N,parameter Nr,parameter Nk)(datain,key,state,reset,clk,start);
input [127:0] datain;
input [N-1:0] key;
output reg [127:0] state;
input reset;
input clk;
output reg start;
wire [(128*(Nr+1))-1:0] keys;
reg [127:0] a1;
wire [127:0] a2;
wire [127:0] a3;
reg [127:0] a4;
wire [127:0] b1;
wire [127:0] b2;
wire [127:0] b3;
integer i = - Nr - 1;
always @(posedge clk or posedge reset)begin
if(reset) begin
i = - Nr - 1;
state=128'hx;
a1 = 128'hx;
a4 = 128'hx;
start = 0;
end
else begin
if( i == 0)begin
a1 = a3;
state=a3;
i = i + 1;
start = 1;
end
else if(i > 0 && i < Nr - 1) begin
a1 = a2;
state=a2;
i = i + 1;
start = 1;
end
else if(i == Nr - 1 ) begin
a4=a2;
state=a2;
i = i + 1;
start = 1;
end
else if(i >= Nr ) begin
state=b3;
start = 1;
end
else begin
i = i + 1;
end
end
end
KeyExpansion #(N,Nr,Nk) ke (key, keys);
Addroundkey ark(datain, keys[127:0], a3);
invround ir(a1, a2, keys[128 * (i) +: 128]);
invShiftBytes ishb(a4,b1);
invsubBytes isb(b1,b2);
Addroundkey eark(b2,keys[128*Nr +: 128],b3);
endmodule