//======================================================================
//
// sha1_core.v
// -----------
// Verilog 2001 implementation of the SHA-1 hash function.
// This is the internal core with wide interfaces.
//
//
// Author: Joachim Strombergson
// Copyright (c) 2014 SUNET
//
// Redistribution and use in source and binary forms, with or
// without modification, are permitted provided that the following
// conditions are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//======================================================================
module sha1_core(
input wire clk,
input wire reset_n,
input wire init,
input wire next,
input wire [511 : 0] block,
output wire ready,
output wire [159 : 0] digest,
output wire digest_valid
);
//----------------------------------------------------------------
// Internal constant and parameter definitions.
//----------------------------------------------------------------
parameter H0_0 = 32'h67452301;
parameter H0_1 = 32'hefcdab89;
parameter H0_2 = 32'h98badcfe;
parameter H0_3 = 32'h10325476;
parameter H0_4 = 32'hc3d2e1f0;
parameter SHA1_ROUNDS = 79;
parameter CTRL_IDLE = 0;
parameter CTRL_ROUNDS = 1;
parameter CTRL_DONE = 2;
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
reg [31 : 0] a_reg;
reg [31 : 0] a_new;
reg [31 : 0] b_reg;
reg [31 : 0] b_new;
reg [31 : 0] c_reg;
reg [31 : 0] c_new;
reg [31 : 0] d_reg;
reg [31 : 0] d_new;
reg [31 : 0] e_reg;
reg [31 : 0] e_new;
reg a_e_we;
reg [31 : 0] H0_reg;
reg [31 : 0] H0_new;
reg [31 : 0] H1_reg;
reg [31 : 0] H1_new;
reg [31 : 0] H2_reg;
reg [31 : 0] H2_new;
reg [31 : 0] H3_reg;
reg [31 : 0] H3_new;
reg [31 : 0] H4_reg;
reg [31 : 0] H4_new;
reg H_we;
reg [6 : 0] round_ctr_reg;
reg [6 : 0] round_ctr_new;
reg round_ctr_we;
reg round_ctr_inc;
reg round_ctr_rst;
reg digest_valid_reg;
reg digest_valid_new;
reg digest_valid_we;
reg [1 : 0] sha1_ctrl_reg;
reg [1 : 0] sha1_ctrl_new;
reg sha1_ctrl_we;
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
reg digest_init;
reg digest_update;
reg state_init;
reg state_update;
reg first_block;
reg ready_flag;
reg w_init;
reg w_next;
wire w_ready;
wire [31 : 0] w;
//----------------------------------------------------------------
// Module instantiantions.
//----------------------------------------------------------------
sha1_w_mem w_mem(
.clk(clk),
.reset_n(reset_n),
.block(block),
.init(w_init),
.next(w_next),
.w(w)
);
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
assign ready = ready_flag;
assign digest = {H0_reg, H1_reg, H2_reg, H3_reg, H4_reg};
assign digest_valid = digest_valid_reg;
//----------------------------------------------------------------
// reg_update
// Update functionality for all registers in the core.
// All registers are positive edge triggered with synchronous
// active low reset. All registers have write enable.
//----------------------------------------------------------------
always @ (posedge clk)
begin : reg_update
if (!reset_n)
begin
a_reg <= 32'h00000000;
b_reg <= 32'h00000000;
c_reg <= 32'h00000000;
d_reg <= 32'h00000000;
e_reg <= 32'h00000000;
H0_reg <= 32'h00000000;
H1_reg <= 32'h00000000;
H2_reg <= 32'h00000000;
H3_reg <= 32'h00000000;
H4_reg <= 32'h00000000;
digest_valid_reg <= 0;
round_ctr_reg <= 7'b0000000;
sha1_ctrl_reg <= CTRL_IDLE;
end
else
begin
if (a_e_we)
begin
a_reg <= a_new;
b_reg <= b_new;
c_reg <= c_new;
d_reg <= d_new;
e_reg <= e_new;
end
if (H_we)
begin
H0_reg <= H0_new;
H1_reg <= H1_new;
H2_reg <= H2_new;
H3_reg <= H3_new;
H4_reg <= H4_new;
end
if (round_ctr_we)
begin
round_ctr_reg <= round_ctr_new;
end
if (digest_valid_we)
begin
digest_valid_reg <= digest_valid_new;
end
if (sha1_ctrl_we)
begin
sha1_ctrl_reg <= sha1_ctrl_new;
end
end
end // reg_update
//----------------------------------------------------------------
// digest_logic
//
// The logic needed to init as well as update the digest.
//----------------------------------------------------------------
always @*
begin : digest_logic
H0_new = 32'h00000000;
H1_new = 32'h00000000;
H2_new = 32'h00000000;
H3_new = 32'h00000000;
H4_new = 32'h00000000;
H_we = 0;
if (digest_init)
begin
H0_new = H0_0;
H1_new = H0_1;
H2_new = H0_2;
H3_new = H0_3;
H4_new = H0_4;
H_we = 1;
end
if (digest_update)
begin
H0_new = H0_reg + a_reg;
H1_new = H1_reg + b_reg;
H2_new = H2_reg + c_reg;
H3_new = H3_reg + d_reg;
H4_new = H4_reg + e_reg;
H_we = 1;
end
end // digest_logic
//----------------------------------------------------------------
// state_logic
//
// The logic needed to init as well as update the state during
// round processing.
//----------------------------------------------------------------
always @*
begin : state_logic
reg [31 : 0] a5;
reg [31 : 0] f;
reg [31 : 0] k;
reg [31 : 0] t;
a5 = 32'h00000000;
f = 32'h00000000;
k = 32'h00000000;
t = 32'h00000000;
a_new = 32'h00000000;
b_new = 32'h00000000;
c_new = 32'h00000000;
d_new = 32'h00000000;
e_new = 32'h00000000;
a_e_we = 0;
if (state_init)
begin
if (first_block)
begin
a_new = H0_0;
b_new = H0_1;
c_new = H0_2;
d_new = H0_3;
e_new = H0_4;
a_e_we = 1;
end
else
begin
a_new = H0_reg;
b_new = H1_reg;
c_new = H2_reg;
d_new = H3_reg;
e_new = H4_reg;
a_e_we = 1;
end
end
if (state_update)
begin
if (round_ctr_reg <= 19)
begin
k = 32'h5a827999;
f = ((b_reg & c_reg) ^ (~b_reg & d_reg));
end
else if ((round_ctr_reg >= 20) && (round_ctr_reg <= 39))
begin
k = 32'h6ed9eba1;
f = b_reg ^ c_reg ^ d_reg;
end
else if ((round_ctr_reg >= 40) && (round_ctr_reg <= 59))
begin
k = 32'h8f1bbcdc;
f = ((b_reg | c_reg) ^ (b_reg | d_reg) ^ (c_reg | d_reg));
end
else if (round_ctr_reg >= 60)
begin
k = 32'hca62c1d6;
f = b_reg ^ c_reg ^ d_reg;
end
a5 = {a_reg[26 : 0], a_reg[31 : 27]};
t = a5 + e_reg + f + k + w;
a_new = t;
b_new = a_reg;
c_new = {b_reg[1 : 0], b_reg[31 : 2]};
d_new = c_reg;
e_new = d_reg;
a_e_we = 1;
end
end // state_logic
//----------------------------------------------------------------
// round_ctr
//
// Update logic for the round counter, a monotonically
// increasing counter with reset.
//----------------------------------------------------------------
always @*
begin : round_ctr
round_ctr_new = 0;
round_ctr_we = 0;
if (round_ctr_rst)
begin
round_ctr_new = 0;
round_ctr_we = 1;
end
if (round_ctr_inc)
begin
round_ctr_new = round_ctr_reg + 1'b1;
round_ctr_we = 1;
end
end // round_ctr
//----------------------------------------------------------------
// sha1_ctrl_fsm
// Logic for the state machine controlling the core behaviour.
//----------------------------------------------------------------
always @*
begin : sha1_ctrl_fsm
digest_init = 0;
digest_update = 0;
state_init = 0;
state_update = 0;
first_block = 0;
ready_flag = 0;
w_init = 0;
w_next = 0;
round_ctr_inc = 0;
round_ctr_rst = 0;
digest_valid_new = 0;
digest_valid_we = 0;
sha1_ctrl_new = CTRL_IDLE;
sha1_ctrl_we = 0;
case (sha1_ctrl_reg)
CTRL_IDLE:
begin
ready_flag = 1;
if (init)
begin
digest_init = 1;
w_init = 1;
state_init = 1;
first_block = 1;
round_ctr_rst = 1;
digest_valid_new = 0;
digest_valid_we = 1;
sha1_ctrl_new = CTRL_ROUNDS;
sha1_ctrl_we = 1;
end
if (next)
begin
w_init = 1;
state_init = 1;
round_ctr_rst = 1;
digest_valid_new = 0;
digest_valid_we = 1;
sha1_ctrl_new = CTRL_ROUNDS;
sha1_ctrl_we = 1;
end
end
CTRL_ROUNDS:
begin
state_update = 1;
round_ctr_inc = 1;
w_next = 1;
if (round_ctr_reg == SHA1_ROUNDS)
begin
sha1_ctrl_new = CTRL_DONE;
sha1_ctrl_we = 1;
end
end
CTRL_DONE:
begin
digest_update = 1;
digest_valid_new = 1;
digest_valid_we = 1;
sha1_ctrl_new = CTRL_IDLE;
sha1_ctrl_we = 1;
end
endcase // case (sha1_ctrl_reg)
end // sha1_ctrl_fsm
endmodule // sha1_core
//======================================================================
// EOF sha1_core.v
//======================================================================
