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-rw-r--r--src/rtl/modexp.v348
1 files changed, 252 insertions, 96 deletions
diff --git a/src/rtl/modexp.v b/src/rtl/modexp.v
index d64a556..9f3d4f0 100644
--- a/src/rtl/modexp.v
+++ b/src/rtl/modexp.v
@@ -71,35 +71,38 @@ module modexp(
localparam ADDR_NAME0 = 8'h00;
localparam ADDR_NAME1 = 8'h01;
localparam ADDR_VERSION = 8'h02;
- localparam ADDR_CTRL = 8'h03;
+ localparam ADDR_CTRL = 8'h08;
localparam CTRL_INIT_BIT = 0;
localparam CTRL_NEXT_BIT = 1;
localparam ADDR_STATUS = 8'h09;
+ localparam STATUS_READY_BIT = 0;
+
+ localparam ADDR_MODULUS_LENGTH = 8'h20;
+ localparam ADDR_EXPONENT_LENGTH = 8'h21;
+ localparam ADDR_LENGTH = 8'h22; // Should be deprecated.
- localparam ADDR_MODSIZE = 8'h20;
- localparam ADDR_LENGTH = 8'h21;
- localparam ADDR_EXPONENT = 8'h22;
localparam MODULUS_PREFIX = 4'h1;
localparam ADDR_MODULUS_START = 8'h00;
localparam ADDR_MODULUS_END = 8'hff;
+
localparam EXPONENT_PREFIX = 4'h2;
localparam ADDR_EXPONENT_START = 8'h00;
localparam ADDR_EXPONENT_END = 8'hff;
+
localparam MESSAGE_PREFIX = 4'h3;
localparam MESSAGE_START = 8'h00;
localparam MESSAGE_END = 8'hff;
+
localparam RESULT_PREFIX = 4'h4;
localparam RESULT_START = 8'h00;
localparam RESULT_END = 8'hff;
- localparam LENGTH_PREFIX = 4'h5;
-
localparam DEFAULT_MODLENGTH = 8'h80;
localparam DEFAULT_EXPLENGTH = 8'h80;
@@ -107,7 +110,7 @@ module modexp(
localparam MONTPROD_SELECT_X_NR = 3'h1;
localparam MONTPROD_SELECT_Z_P = 3'h2;
localparam MONTPROD_SELECT_P_P = 3'h3;
- localparam MONTPROD_SELECT_ONE_Z = 3'h4;
+ localparam MONTPROD_SELECT_Z_ONE = 3'h4;
localparam MONTPROD_DEST_Z = 2'b00;
localparam MONTPROD_DEST_P = 2'b01;
@@ -124,53 +127,36 @@ module modexp(
localparam CTRL_CALCULATE_ZN = 4'h8;
localparam CTRL_DONE = 4'h9;
+ localparam EXPONATION_MODE_SECRET_SECURE = 1'b0;
+ localparam EXPONATION_MODE_PUBLIC_FAST = 1'b1; //for rsa, c=M^65537 etc, there is no need to slow down to hide the exponent
+
+
localparam CORE_NAME0 = 32'h6d6f6465; // "mode"
localparam CORE_NAME1 = 32'h78702020; // "xp "
- localparam CORE_VERSION = 32'h302e3031; // "0.01"
+ localparam CORE_VERSION = 32'h302e3530; // "0.50"
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
- reg [07 : 0] modulus_mem_int_rd_addr;
- wire [31 : 0] modulus_mem_int_rd_data;
- wire [31 : 0] modulus_mem_api_rd_data;
- reg modulus_mem_api_we;
-
- reg [07 : 0] message_mem_int_rd_addr;
- wire [31 : 0] message_mem_int_rd_data;
- wire [31 : 0] message_mem_api_rd_data;
- reg message_mem_api_we;
-
- reg [07 : 0] exponent_mem_int_rd_addr;
- wire [31 : 0] exponent_mem_int_rd_data;
- wire [31 : 0] exponent_mem_api_rd_data;
- reg exponent_mem_api_we;
+ reg [07 : 0] exponent_length_reg;
+ reg [07 : 0] exponent_length_new;
+ reg exponent_length_we;
- wire [31 : 0] result_mem_api_rd_data;
- reg [07 : 0] result_mem_int_rd_addr;
- wire [31 : 0] result_mem_int_rd_data;
- reg [07 : 0] result_mem_int_wr_addr;
- reg [31 : 0] result_mem_int_wr_data;
- reg result_mem_int_we;
-
- reg [07 : 0] p_mem_rd0_addr;
- wire [31 : 0] p_mem_rd0_data;
- reg [07 : 0] p_mem_rd1_addr;
- wire [31 : 0] p_mem_rd1_data;
- reg [07 : 0] p_mem_wr_addr;
- reg [31 : 0] p_mem_wr_data;
- reg p_mem_we;
+ reg [07 : 0] modulus_length_reg;
+ reg [07 : 0] modulus_length_new;
+ reg modulus_length_we;
reg [07 : 0] length_reg;
+ reg [07 : 0] length_new;
reg [07 : 0] length_m1_reg;
- reg [07 : 0] length_new; //TODO: API should write length!!!
- reg [07 : 0] length_m1_new; //TODO: API should write length-1 when writing length!!!
- reg length_we; //TODO: API should enable length_we!!!
+ reg [07 : 0] length_m1_new;
+ reg length_we;
reg start_reg;
- reg start_new; //TODO: API should start operations!!!
- reg start_we; //TODO: API should start operations!!!
+ reg start_new;
+ reg start_we;
+ reg clear_start;
reg ready_reg;
reg ready_new;
@@ -187,22 +173,61 @@ module modexp(
reg [3 : 0] modexp_ctrl_new;
reg modexp_ctrl_we;
- reg [31 : 0] one;
+ reg [31 : 0] one_reg;
reg [31 : 0] one_new;
+ reg [31 : 0] b_one_reg;
+ reg [31 : 0] b_one_new;
reg [12 : 0] loop_counter_reg;
reg [12 : 0] loop_counter_new;
reg loop_counter_we;
+
reg [07 : 0] E_word_index;
reg [04 : 0] E_bit_index;
reg last_iteration;
+
reg ei_reg;
reg ei_new;
reg ei_we;
+ reg exponation_mode_reg;
+ reg exponation_mode_new;
+ reg exponation_mode_we;
+
+
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
+ reg [07 : 0] modulus_mem_int_rd_addr;
+ wire [31 : 0] modulus_mem_int_rd_data;
+ wire [31 : 0] modulus_mem_api_rd_data;
+ reg modulus_mem_api_we;
+
+ reg [07 : 0] message_mem_int_rd_addr;
+ wire [31 : 0] message_mem_int_rd_data;
+ wire [31 : 0] message_mem_api_rd_data;
+ reg message_mem_api_we;
+
+ reg [07 : 0] exponent_mem_int_rd_addr;
+ wire [31 : 0] exponent_mem_int_rd_data;
+ wire [31 : 0] exponent_mem_api_rd_data;
+ reg exponent_mem_api_we;
+
+ wire [31 : 0] result_mem_api_rd_data;
+ reg [07 : 0] result_mem_int_rd_addr;
+ wire [31 : 0] result_mem_int_rd_data;
+ reg [07 : 0] result_mem_int_wr_addr;
+ reg [31 : 0] result_mem_int_wr_data;
+ reg result_mem_int_we;
+
+ reg [07 : 0] p_mem_rd0_addr;
+ wire [31 : 0] p_mem_rd0_data;
+ reg [07 : 0] p_mem_rd1_addr;
+ wire [31 : 0] p_mem_rd1_data;
+ reg [07 : 0] p_mem_wr_addr;
+ reg [31 : 0] p_mem_wr_data;
+ reg p_mem_we;
+
reg [31 : 0] tmp_read_data;
//reg tmp_error;
@@ -225,7 +250,7 @@ module modexp(
reg residue_calculate;
wire residue_ready;
- reg [14 : 0] residue_nn;
+ reg [14 : 0] residue_nn;
reg [07 : 0] residue_length;
wire [07 : 0] residue_opa_rd_addr;
wire [31 : 0] residue_opa_rd_data;
@@ -238,6 +263,11 @@ module modexp(
reg [07 : 0] residue_mem_montprod_read_addr;
wire [31 : 0] residue_mem_montprod_read_data;
+ reg residue_valid_reg;
+ reg residue_valid_new;
+ reg invalidate_residue;
+ reg residue_valid_int_validated;
+
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
@@ -368,18 +398,37 @@ module modexp(
begin
if (!reset_n)
begin
+ exponent_length_reg <= DEFAULT_EXPLENGTH;
+ modulus_length_reg <= DEFAULT_MODLENGTH;
+ start_reg <= 1'b0;
ready_reg <= 1'b1;
montprod_select_reg <= MONTPROD_SELECT_ONE_NR;
montprod_dest_reg <= MONTPROD_DEST_NOWHERE;
modexp_ctrl_reg <= CTRL_IDLE;
- one <= 32'h0;
+ one_reg <= 32'h0;
+ b_one_reg <= 32'h0;
length_reg <= 8'h0;
length_m1_reg <= 8'h0;
loop_counter_reg <= 13'b0;
ei_reg <= 1'b0;
+ residue_valid_reg <= 1'b0;
+ exponation_mode_reg <= EXPONATION_MODE_SECRET_SECURE;
end
else
begin
+ one_reg <= one_new;
+ b_one_reg <= b_one_new;
+ residue_valid_reg <= residue_valid_new;
+
+ if (exponent_length_we)
+ exponent_length_reg <= exponent_length_new;
+
+ if (modulus_length_we)
+ modulus_length_reg <= modulus_length_new;
+
+ if (start_we)
+ start_reg <= start_new;
+
if (ready_we)
ready_reg <= ready_new;
@@ -394,8 +443,8 @@ module modexp(
if (length_we)
begin
- length_reg <= write_data[7 : 0];
- length_m1_reg <= write_data[7 : 0] - 8'h1;
+ length_reg <= length_new;
+ length_m1_reg <= length_m1_new;
end
if (loop_counter_we)
@@ -404,7 +453,8 @@ module modexp(
if (ei_we)
ei_reg <= ei_new;
- one <= one_new;
+ if (exponation_mode_we)
+ exponation_mode_reg <= exponation_mode_new;
end
end // reg_update
@@ -416,12 +466,35 @@ module modexp(
//----------------------------------------------------------------
always @*
begin : api
+ modulus_length_we = 1'b0;
+ exponent_length_we = 1'b0;
+ start_new = 1'b0;
+ start_we = 1'b0;
modulus_mem_api_we = 1'b0;
exponent_mem_api_we = 1'b0;
message_mem_api_we = 1'b0;
length_we = 1'b0;
+ invalidate_residue = 1'b0;
+
+ //TODO: Add API code to enable fast exponation for working with public exponents.
+ exponation_mode_we = 1'b0;
+
+ exponation_mode_new = EXPONATION_MODE_SECRET_SECURE;
+ modulus_length_new = write_data[7 : 0];
+ exponent_length_new = write_data[7 : 0];
+ length_new = write_data[7 : 0];
+ length_m1_new = write_data[7 : 0] - 8'h1;
+
tmp_read_data = 32'h00000000;
+ // We need to be able to clear start bit after we have
+ // started a modexp operation.
+ if (clear_start)
+ begin
+ start_new = 1'b0;
+ start_we = 1'b1;
+ end
+
if (cs)
begin
case (address[11 : 8])
@@ -430,8 +503,26 @@ module modexp(
if (we)
begin
case (address[7 : 0])
+ ADDR_CTRL:
+ begin
+ start_new = write_data[0];
+ start_we = 1'b1;
+ end
+
ADDR_LENGTH:
- length_we = 1'b1;
+ begin
+ length_we = 1'b1;
+ end
+
+ ADDR_MODULUS_LENGTH:
+ begin
+ modulus_length_we = 1'b1;
+ end
+
+ ADDR_EXPONENT_LENGTH:
+ begin
+ exponent_length_we = 1'b1;
+ end
default:
begin
@@ -451,10 +542,16 @@ module modexp(
tmp_read_data = CORE_VERSION;
ADDR_CTRL:
- tmp_read_data = 32'h00000000;
+ tmp_read_data = {31'h00000000, start_reg};
ADDR_STATUS:
- tmp_read_data = 32'h00000000;
+ tmp_read_data = {31'h00000000, ready_reg};
+
+ ADDR_MODULUS_LENGTH:
+ tmp_read_data = {24'h000000, modulus_length_reg};
+
+ ADDR_EXPONENT_LENGTH:
+ tmp_read_data = {24'h000000, exponent_length_reg};
ADDR_LENGTH:
tmp_read_data = {24'h000000, length_reg};
@@ -471,6 +568,7 @@ module modexp(
if (we)
begin
modulus_mem_api_we = 1'b1;
+ invalidate_residue = 1'b1;
end
else
begin
@@ -522,15 +620,19 @@ module modexp(
// generates the big integer one ( 00... 01 )
//----------------------------------------------------------------
always @*
- begin : one_process;
+ begin : one_process
+ one_new = 32'h00000000;
+ b_one_new = 32'h00000000;
if (montprod_opa_addr == length_m1_reg)
one_new = 32'h00000001;
- else
- one_new = 32'h00000000;
+ if (montprod_opb_addr == length_m1_reg)
+ b_one_new = 32'h00000001;
end
+
//----------------------------------------------------------------
- // read mux for modulus, since it is being addressed by two sources
+ // Read mux for modulus. Needed since it is being
+ // addressed by two sources.
//----------------------------------------------------------------
always @*
begin : modulus_mem_reader_process
@@ -540,21 +642,38 @@ module modexp(
modulus_mem_int_rd_addr = montprod_opm_addr;
end
+
//----------------------------------------------------------------
- // feeds residue calculator
+ // Feeds residue calculator.
//----------------------------------------------------------------
always @*
- begin : residue_process;
- residue_nn = { 1'b0, length_reg, 6'h0 }; //N*2, N=length*32, *32 = shl5, *64 = shl6
+ begin : residue_process
+ //N*2, N=length*32, *32 = shl5, *64 = shl6
+ residue_nn = { 1'b0, length_reg, 6'h0 };
residue_length = length_reg;
residue_opm_data = modulus_mem_int_rd_data;
end
+
+ //----------------------------------------------------------------
+ // Sets the register that decides if residue is valid or not.
+ //----------------------------------------------------------------
+ always @*
+ begin : residue_valid_process
+ if (invalidate_residue)
+ residue_valid_new = 1'b0;
+ else if ( residue_valid_int_validated == 1'b1)
+ residue_valid_new = 1'b1;
+ else
+ residue_valid_new = residue_valid_reg;
+ end
+
+
//----------------------------------------------------------------
// montprod_op_select
//
// Select operands used during montprod calculations depending
- // on what operation we want to do
+ // on what operation we want to do.
//----------------------------------------------------------------
always @*
begin : montprod_op_select
@@ -572,7 +691,7 @@ module modexp(
case (montprod_select_reg)
MONTPROD_SELECT_ONE_NR:
begin
- montprod_opa_data = one;
+ montprod_opa_data = one_reg;
montprod_opb_data = residue_mem_montprod_read_data;
end
@@ -594,10 +713,10 @@ module modexp(
montprod_opb_data = p_mem_rd1_data;
end
- MONTPROD_SELECT_ONE_Z:
+ MONTPROD_SELECT_Z_ONE:
begin
- montprod_opa_data = one;
- montprod_opb_data = result_mem_int_rd_data;
+ montprod_opa_data = result_mem_int_rd_data;
+ montprod_opb_data = b_one_reg;
end
default:
@@ -612,7 +731,7 @@ module modexp(
//----------------------------------------------------------------
// memory write mux
//
- // direct memory write signals to correct memory
+ // Direct memory write signals to correct memory.
//----------------------------------------------------------------
always @*
begin : memory_write_process
@@ -643,11 +762,12 @@ module modexp(
//----------------------------------------------------------------
// loop_counter
//
- // Calculate the loop counter and related variables
+ // Calculate the loop counter and related variables.
//----------------------------------------------------------------
always @*
begin : loop_counters_process
- E_bit_index = loop_counter_reg[ 04 : 0 ];
+ loop_counter_new = 13'b0;
+ loop_counter_we = 1'b0;
if (loop_counter_reg == { length_m1_reg, 5'b11111 })
last_iteration = 1'b1;
@@ -669,7 +789,7 @@ module modexp(
default:
begin
- loop_counter_new = 13'b0;
+ loop_counter_new = loop_counter_reg;
loop_counter_we = 1'b0;
end
@@ -680,12 +800,15 @@ module modexp(
//----------------------------------------------------------------
// exponent
//
- // reads the exponent
+ // Reads the exponent.
//----------------------------------------------------------------
always @*
begin : exponent_process
- // accessing new instead of reg - pick up update at CTRL_ITERATE_NEW to remove a pipeline stall
- E_word_index = loop_counter_new[ 12 : 5 ];
+ // Accessing new instead of reg - pick up update at
+ // CTRL_ITERATE_NEW to remove a pipeline stall.
+ E_word_index = length_m1_reg - loop_counter_new[ 12 : 5 ];
+
+ E_bit_index = loop_counter_reg[ 04 : 0 ];
exponent_mem_int_rd_addr = E_word_index;
@@ -705,48 +828,70 @@ module modexp(
//----------------------------------------------------------------
always @*
begin
- ready_new = 0;
- ready_we = 0;
+ ready_new = 1'b0;
+ ready_we = 1'b0;
montprod_select_new = MONTPROD_SELECT_ONE_NR;
montprod_select_we = 0;
montprod_dest_new = MONTPROD_DEST_NOWHERE;
montprod_dest_we = 0;
montprod_calc = 0;
modexp_ctrl_new = CTRL_IDLE;
- modexp_ctrl_we = 0;
+ modexp_ctrl_we = 1'b0;
+ clear_start = 1'b0;
residue_calculate = 1'b0;
+ residue_valid_int_validated = 1'b0;
+
case (modexp_ctrl_reg)
CTRL_IDLE:
begin
- ready_new = 0;
- ready_we = 1;
- if (start_reg == 1'b1)
+ if (start_reg)
begin
- modexp_ctrl_new = CTRL_RESIDUE;
- modexp_ctrl_we = 1;
- residue_calculate = 1'b1;
+ ready_new = 1'b0;
+ ready_we = 1'b1;
+ modexp_ctrl_new = CTRL_DONE;
+ modexp_ctrl_we = 1'b1;
+
+ if (residue_valid_reg)
+ begin
+ //residue has alrady been calculated, start with MONTPROD( 1, Nr, MODULUS )
+ montprod_select_new = MONTPROD_SELECT_ONE_NR;
+ montprod_select_we = 1;
+ montprod_dest_new = MONTPROD_DEST_Z;
+ montprod_dest_we = 1;
+ montprod_calc = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_Z0;
+ modexp_ctrl_we = 1;
+ end
+ else
+ begin
+ //modulus has been written and residue (Nr) must be calculated
+ modexp_ctrl_new = CTRL_RESIDUE;
+ modexp_ctrl_we = 1;
+ residue_calculate = 1'b1;
+ end
end
end
CTRL_RESIDUE:
begin
- if (residue_ready == 1'b1)
+ if (residue_ready)
begin
montprod_select_new = MONTPROD_SELECT_ONE_NR;
montprod_select_we = 1;
montprod_dest_new = MONTPROD_DEST_Z;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_CALCULATE_Z0;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_Z0;
+ modexp_ctrl_we = 1;
+ residue_valid_int_validated = 1'b1; //update registers telling residue is valid
end
end
CTRL_CALCULATE_Z0:
begin
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
montprod_select_new = MONTPROD_SELECT_X_NR;
montprod_select_we = 1;
@@ -774,20 +919,28 @@ module modexp(
montprod_dest_new = MONTPROD_DEST_Z;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_ITERATE_Z_P;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_ITERATE_Z_P;
+ modexp_ctrl_we = 1;
+
+ if (ei_new == 1'b0 && exponation_mode_reg == EXPONATION_MODE_PUBLIC_FAST)
+ begin
+ //Skip the fake montgomery calculation, exponation_mode_reg optimizing for speed not blinding.
+ montprod_select_new = MONTPROD_SELECT_P_P;
+ montprod_dest_new = MONTPROD_DEST_P;
+ modexp_ctrl_new = CTRL_ITERATE_P_P;
+ end
end
CTRL_ITERATE_Z_P:
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
montprod_select_new = MONTPROD_SELECT_P_P;
montprod_select_we = 1;
montprod_dest_new = MONTPROD_DEST_P;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_ITERATE_P_P;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_ITERATE_P_P;
+ modexp_ctrl_we = 1;
end
CTRL_ITERATE_P_P:
@@ -799,24 +952,26 @@ module modexp(
CTRL_ITERATE_END:
begin
- if (last_iteration == 1'b0)
+ if (!last_iteration)
begin
modexp_ctrl_new = CTRL_ITERATE;
modexp_ctrl_we = 1;
end
else
begin
- montprod_select_new = MONTPROD_SELECT_ONE_Z;
+ montprod_select_new = MONTPROD_SELECT_Z_ONE;
montprod_select_we = 1;
+ montprod_dest_new = MONTPROD_DEST_Z;
+ montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_CALCULATE_ZN;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_ZN;
+ modexp_ctrl_we = 1;
end
end
CTRL_CALCULATE_ZN:
begin
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
modexp_ctrl_new = CTRL_DONE;
modexp_ctrl_we = 1;
@@ -825,10 +980,11 @@ module modexp(
CTRL_DONE:
begin
- ready_new = 1;
- ready_we = 1;
- modexp_ctrl_new = CTRL_IDLE;
- modexp_ctrl_we = 1;
+ clear_start = 1'b1;
+ ready_new = 1'b1;
+ ready_we = 1'b1;
+ modexp_ctrl_new = CTRL_IDLE;
+ modexp_ctrl_we = 1;
end
default:
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-23 23:17:19 +0000