// ======================================================================
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// DES encryption/decryption
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// algorithm according:FIPS 46-3 specification
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// Copyright (C) 2012 Torsten Meissner
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//-----------------------------------------------------------------------
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write:the Free Software
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// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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// ======================================================================
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module des
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(
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input reset_i, // async reset
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input clk_i, // clock
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input mode_i, // des-mode: 0 = encrypt, 1 = decrypt
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input [0:63] key_i, // key input
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input [0:63] data_i, // data input
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input valid_i, // input key/data valid flag
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output reg [0:63] data_o, // data output
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output valid_o // output data valid flag
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);
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`include "../../rtl/verilog/des_pkg.v"
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// valid, mode register
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reg [0:18] valid;
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reg [0:17] mode;
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// algorithm pipeline register
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// key calculation register
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reg [0:27] c0;
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reg [0:27] c1;
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reg [0:27] c2;
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reg [0:27] c3;
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reg [0:27] c4;
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reg [0:27] c5;
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reg [0:27] c6;
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reg [0:27] c7;
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reg [0:27] c8;
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reg [0:27] c9;
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reg [0:27] c10;
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reg [0:27] c11;
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reg [0:27] c12;
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reg [0:27] c13;
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reg [0:27] c14;
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reg [0:27] c15;
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reg [0:27] c16;
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reg [0:27] d0;
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reg [0:27] d1;
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reg [0:27] d2;
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reg [0:27] d3;
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reg [0:27] d4;
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reg [0:27] d5;
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reg [0:27] d6;
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reg [0:27] d7;
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reg [0:27] d8;
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reg [0:27] d9;
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reg [0:27] d10;
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reg [0:27] d11;
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reg [0:27] d12;
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reg [0:27] d13;
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reg [0:27] d14;
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reg [0:27] d15;
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reg [0:27] d16;
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// key register
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wire [0:47] key1;
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wire [0:47] key2;
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wire [0:47] key3;
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wire [0:47] key4;
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wire [0:47] key5;
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wire [0:47] key6;
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wire [0:47] key7;
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wire [0:47] key8;
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wire [0:47] key9;
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wire [0:47] key10;
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wire [0:47] key11;
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wire [0:47] key12;
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wire [0:47] key13;
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wire [0:47] key14;
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wire [0:47] key15;
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wire [0:47] key16;
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// register for left, right data blocks
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reg [0:31] l;
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reg [0:31] l0;
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reg [0:31] l1;
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reg [0:31] l2;
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reg [0:31] l3;
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reg [0:31] l4;
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reg [0:31] l5;
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reg [0:31] l6;
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reg [0:31] l7;
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reg [0:31] l8;
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reg [0:31] l9;
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reg [0:31] l10;
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reg [0:31] l11;
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reg [0:31] l12;
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reg [0:31] l13;
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reg [0:31] l14;
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reg [0:31] l15;
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reg [0:31] l16;
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reg [0:31] r;
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reg [0:31] r0;
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reg [0:31] r1;
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reg [0:31] r2;
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reg [0:31] r3;
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reg [0:31] r4;
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reg [0:31] r5;
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reg [0:31] r6;
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reg [0:31] r7;
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reg [0:31] r8;
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reg [0:31] r9;
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reg [0:31] r10;
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reg [0:31] r11;
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reg [0:31] r12;
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reg [0:31] r13;
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reg [0:31] r14;
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reg [0:31] r15;
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reg [0:31] r16;
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wire valid_o = valid[18];
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// valid, mode register
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always @(posedge clk_i, negedge reset_i) begin
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if(~reset_i) begin
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valid <= 0;
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mode <= 0;
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end
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else begin
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// shift registers
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valid[1:18] <= valid[0:17];
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valid[0] <= valid_i;
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mode[1:17] <= mode[0:16];
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mode[0] <= mode_i;
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end
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end
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// des algorithm pipeline
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always @(posedge clk_i, negedge reset_i) begin
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if(~reset_i) begin
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l <= 0;
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r <= 0;
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l0 <= 0;
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l1 <= 0;
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l2 <= 0;
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l3 <= 0;
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l4 <= 0;
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l5 <= 0;
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l6 <= 0;
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l7 <= 0;
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l8 <= 0;
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l9 <= 0;
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l10 <= 0;
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l11 <= 0;
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l12 <= 0;
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l13 <= 0;
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l14 <= 0;
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l15 <= 0;
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l16 <= 0;
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r0 <= 0;
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r1 <= 0;
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r2 <= 0;
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r3 <= 0;
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r4 <= 0;
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r5 <= 0;
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r6 <= 0;
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r7 <= 0;
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r8 <= 0;
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r9 <= 0;
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r10 <= 0;
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r11 <= 0;
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r12 <= 0;
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r13 <= 0;
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r14 <= 0;
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r15 <= 0;
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r16 <= 0;
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data_o <= 0;
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end
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else begin
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// output stage
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data_o <= ipn({r16, l16});
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// 16. stage
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l16 <= r15;
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r16 <= l15 ^ (f(r15, key16));
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// 15. stage
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l15 <= r14;
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r15 <= l14 ^ (f(r14, key15));
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// 14. stage
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l14 <= r13;
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r14 <= l13 ^ (f(r13, key14));
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// 13. stage
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l13 <= r12;
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r13 <= l12 ^ (f(r12, key13));
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// 12. stage
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l12 <= r11;
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r12 <= l11 ^ (f(r11, key12));
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// 11. stage
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l11 <= r10;
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r11 <= l10 ^ (f(r10, key11));
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// 10. stage
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l10 <= r9;
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r10 <= l9 ^ (f(r9, key10));
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// 9. stage
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l9 <= r8;
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r9 <= l8 ^ (f(r8, key9));
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// 8. stage
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l8 <= r7;
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r8 <= l7 ^ (f(r7, key8));
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// 7. stage
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l7 <= r6;
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r7 <= l6 ^ (f(r6, key7));
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// 6. stage
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l6 <= r5;
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r6 <= l5 ^ (f(r5, key6));
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// 5. stage
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l5 <= r4;
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r5 <= l4 ^ (f(r4, key5));
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// 4. stage
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l4 <= r3;
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r4 <= l3 ^ (f(r3, key4));
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// 3. stage
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l3 <= r2;
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r3 <= l2 ^ (f(r2, key3));
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// 2. stage
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l2 <= r1;
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r2 <= l1 ^ (f(r1, key2));
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// 1. stage
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l1 <= r0;
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r1 <= l0 ^ (f(r0, key1));
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// 1. state
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l0 <= l;
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r0 <= r;
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// input stage
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l <= ip0(data_i);
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r <= ip1(data_i);
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end
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end
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// des key pipeline
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always @(posedge clk_i, negedge reset_i) begin
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if(~reset_i) begin
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c0 <= 0;
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c1 <= 0;
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c2 <= 0;
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c3 <= 0;
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c4 <= 0;
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c5 <= 0;
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c6 <= 0;
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c7 <= 0;
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c8 <= 0;
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c9 <= 0;
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c10 <= 0;
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c11 <= 0;
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c12 <= 0;
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c13 <= 0;
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c14 <= 0;
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c15 <= 0;
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c16 <= 0;
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d0 <= 0;
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d1 <= 0;
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d2 <= 0;
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d3 <= 0;
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d4 <= 0;
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d5 <= 0;
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d6 <= 0;
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d7 <= 0;
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d8 <= 0;
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d9 <= 0;
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d10 <= 0;
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d11 <= 0;
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d12 <= 0;
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d13 <= 0;
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d14 <= 0;
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d15 <= 0;
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d16 <= 0;
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end
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else begin
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// input stage
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c0 <= pc1_c(key_i);
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d0 <= pc1_d(key_i);
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// 1st stage
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if (~mode[0]) begin
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c1 <= {c0[1:27], c0[0]};
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d1 <= {c0[1:27], c0[0]};
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end
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else begin
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c1 <= c0;
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d1 <= d0;
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end
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// 2nd stage
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if (~mode[1]) begin
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c2 <= {c1[1:27], c1[0]};
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d2 <= {d1[1:27], d1[0]};
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end
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else begin
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c2 <= {c1[27], c1[0:26]};
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d2 <= {d1[27], d1[0:26]};
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end
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// 3rd stage
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if (~mode[2]) begin
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c3 <= {c2[2:27], c2[0:1]};
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d3 <= {d2[2:27], d2[0:1]};
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end
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else begin
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c3 <= {c2[26:27], c2[0:25]};
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d3 <= {d2[26:27], d2[0:25]};
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end
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// 4th stage
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if (~mode[3]) begin
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c4 <= {c3[2:27], c3[0:1]};
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d4 <= {d3[2:27], d3[0:1]};
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end
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else begin
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c4 <= {c3[26:27], c3[0:25]};
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d4 <= {d3[26:27], d3[0:25]};
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end
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// 5th stage
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if (~mode[4]) begin
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c5 <= {c4[2:27], c4[0:1]};
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d5 <= {d4[2:27], d4[0:1]};
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end
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else begin
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c5 <= {c4[26:27], c4[0:25]};
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d5 <= {d4[26:27], d4[0:25]};
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end
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// 6. stage
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if (~mode[5]) begin
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c6 <= {c5[2:27], c5[0:1]};
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d6 <= {d5[2:27], d5[0:1]};
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end
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else begin
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c6 <= {c5[26:27], c5[0:25]};
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d6 <= {d5[26:27], d5[0:25]};
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end
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// 7. stage
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if (~mode[6]) begin
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c7 <= {c6[2:27], c6[0:1]};
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d7 <= {d6[2:27], d6[0:1]};
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end
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else begin
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c7 <= {c6[26:27], c6[0:25]};
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d7 <= {d6[26:27], d6[0:25]};
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end
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// 8. stage
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if (~mode[7]) begin
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c8 <= {c7[2:27], c7[0:1]};
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d8 <= {d7[2:27], d7[0:1]};
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end
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else begin
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c8 <= {c7[26:27], c7[0:25]};
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d8 <= {d7[26:27], d7[0:25]};
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end
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// 9. stage
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if (~mode[8]) begin
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c9 <= {c8[2:27], c8[0:1]};
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d9 <= {d8[2:27], d8[0:1]};
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end
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else begin
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c9 <= {c8[26:27], c8[0:25]};
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d9 <= {d8[26:27], d8[0:25]};
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end
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// 10. stage
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if (~mode[9]) begin
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c10 <= {c9[2:27], c9[0:1]};
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d10 <= {d9[2:27], d9[0:1]};
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end
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else begin
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c10 <= {c9[26:27], c9[0:25]};
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d10 <= {d9[26:27], d9[0:25]};
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end
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// 6. stage
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if (~mode[10]) begin
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c11 <= {c10[2:27], c10[0:1]};
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d11 <= {d10[2:27], d10[0:1]};
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end
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else begin
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c11 <= {c10[26:27], c10[0:25]};
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d11 <= {d10[26:27], d10[0:25]};
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end
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// 6. stage
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if (~mode[11]) begin
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c12 <= {c11[2:27], c11[0:1]};
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d12 <= {d11[2:27], d11[0:1]};
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end
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else begin
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c12 <= {c11[26:27], c11[0:25]};
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d12 <= {d11[26:27], d11[0:25]};
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end
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// 6. stage
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if (~mode[12]) begin
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c13 <= {c12[2:27], c12[0:1]};
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d13 <= {d12[2:27], d12[0:1]};
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end
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else begin
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c13 <= {c12[26:27], c12[0:25]};
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d13 <= {d12[26:27], d12[0:25]};
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end
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// 6. stage
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if (~mode[13]) begin
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c14 <= {c13[2:27], c13[0:1]};
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d14 <= {d13[2:27], d13[0:1]};
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end
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else begin
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c14 <= {c13[26:27], c13[0:25]};
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d14 <= {d13[26:27], d13[0:25]};
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end
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// 6. stage
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if (~mode[14]) begin
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c15 <= {c14[2:27], c14[0:1]};
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d15 <= {d14[2:27], d14[0:1]};
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end
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else begin
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c15 <= {c14[26:27], c14[0:25]};
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d15 <= {d14[26:27], d14[0:25]};
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end
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// 6. stage
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if (~mode[15]) begin
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c16 <= {c15[1:27], c15[0]};
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d16 <= {d15[1:27], d15[0]};
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end
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else begin
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c16 <= {c15[27], c15[0:26]};
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d16 <= {d15[27], d15[0:26]};
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end
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end
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end
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// key assignments
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assign key1 = pc2({c1, d1});
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assign key2 = pc2({c2, d2});
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assign key3 = pc2({c3, d3});
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assign key4 = pc2({c4, d4});
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assign key5 = pc2({c5, d5});
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assign key6 = pc2({c6, d6});
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assign key7 = pc2({c7, d7});
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assign key8 = pc2({c8, d8});
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assign key9 = pc2({c9, d9});
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assign key10 = pc2({c10, d10});
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assign key11 = pc2({c11, d11});
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assign key12 = pc2({c12, d12});
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assign key13 = pc2({c13, d13});
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assign key14 = pc2({c14, d14});
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assign key15 = pc2({c15, d15});
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assign key16 = pc2({c16, d16});
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endmodule
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