Added more test vectors to trigger the virtually never taken path in the curve

point addition routine.

2 files changed, 52 insertions, 215 deletions

diff --git a/stm32_driver/ecdsa256_driver_sample.c b/stm32_driver/ecdsa256_driver_sample.c
index 8047e98..fcfd3ae 100644
--- a/stm32_driver/ecdsa256_driver_sample.c
+++ b/stm32_driver/ecdsa256_driver_sample.c
@@ -1,5 +1,5 @@
 //
-// simple driver to test "ecdsa384" core in hardware
+// simple driver to test "ecdsa256" core in hardware
 //
 
 //
@@ -31,7 +31,7 @@
 // curve selection
 #define USE_CURVE			1
 
-#include "ecdsa_model.h"
+#include "../../../user/shatov/ecdsa_fpga_model/ecdsa_model.h"
 
 #define BUF_NUM_WORDS		(OPERAND_WIDTH / (sizeof(uint32_t) << 3))	// 8
 
@@ -50,9 +50,16 @@ static const uint32_t p256_i[BUF_NUM_WORDS]  = ECDSA_ONE;
 static const uint32_t p256_gx[BUF_NUM_WORDS] = ECDSA_G_X;
 static const uint32_t p256_gy[BUF_NUM_WORDS] = ECDSA_G_Y;
 
+static const uint32_t p256_hx[BUF_NUM_WORDS] = ECDSA_H_X;
+static const uint32_t p256_hy[BUF_NUM_WORDS] = ECDSA_H_Y;
+
 static const uint32_t p256_z[BUF_NUM_WORDS]  = ECDSA_ZERO;
 static const uint32_t p256_n[BUF_NUM_WORDS]  = ECDSA_N;
 
+static uint32_t p256_2[BUF_NUM_WORDS];	// 2
+static uint32_t p256_n1[BUF_NUM_WORDS];	// n + 1
+static uint32_t p256_n2[BUF_NUM_WORDS];	// n + 2
+
 //
 // prototypes
 //
@@ -88,20 +95,54 @@ int main()
     while (1);
   }
 
+	// prepare more numbers
+	size_t w;
+	for (w=0; w<BUF_NUM_WORDS; w++)
+	{	p256_2[w]  = p256_z[w];	// p256_2 = p256_z = 0
+		p256_n1[w] = p256_n[w];	// p256_n1 = p256_n = N
+		p256_n2[w] = p256_n[w];	// p256_n2 = p256_n = N
+	}
+	
+	p256_2[BUF_NUM_WORDS-1]  += 2;	// p256_2 = 2
+	p256_n1[BUF_NUM_WORDS-1] += 1;	// p256_n1 = N + 1
+	p256_n2[BUF_NUM_WORDS-1] += 2;	// p256_n2 = N + 2
+	
+	
+	
   // repeat forever
   while (1)
     {
       ok = 1;
-      ok = ok && test_p256_multiplier(p256_d, p256_qx, p256_qy);
-      ok = ok && test_p256_multiplier(p256_k, p256_rx, p256_ry);
-      ok = ok && test_p256_multiplier(p256_z, p256_z,  p256_z);
-      ok = ok && test_p256_multiplier(p256_i, p256_gx, p256_gy);
-      ok = ok && test_p256_multiplier(p256_n, p256_z,  p256_z);
-
+			
+      ok = ok && test_p256_multiplier(p256_d, p256_qx, p256_qy);	/* Q = d * G */
+      ok = ok && test_p256_multiplier(p256_k, p256_rx, p256_ry);	/* R = k * G */
+			
+      ok = ok && test_p256_multiplier(p256_z, p256_z,  p256_z);		/* O = 0 * G */
+      ok = ok && test_p256_multiplier(p256_i, p256_gx, p256_gy);	/* G = 1 * G */
+			
+      ok = ok && test_p256_multiplier(p256_n, p256_z,  p256_z);		/* O = n * G */
+
+			ok = ok && test_p256_multiplier(p256_n1, p256_gx, p256_gy);	/* G = (n + 1) * G */
+			
+			//
+			// The following two vectors test the virtually never taken path in the curve point
+			// addition routine when both input points are the same. During the first test (2 * G)
+			// the double of the base point is computed at the second doubling step of the multiplication
+			// algorithm, which does not require any special handling. During the second test the
+			// precomputed double of the base point (stored in internal read-only memory) is returned,
+			// because after doubling of G * ((n + 1) / 2) we get G * (n + 1) = G. The adder then has to
+			// compute G + G for which the formulae don't work, and special handling is required. The two
+			// test vectors verify that the hardcoded double of the base point matches the one computed
+			// on the fly. Note that in practice one should never be multiplying by anything larger than (n-1),
+			// because both the secret key and the per-message (random) number must be from [1, n-1].
+			//
+			ok = ok && test_p256_multiplier(p256_2, p256_hx, p256_hy);	/* H = 2 * G */
+			ok = ok && test_p256_multiplier(p256_n2, p256_hx, p256_hy);	/* H = (n + 2) * G */			
+			
       if (!ok) {
-	led_off(LED_GREEN);
-	led_on(LED_RED);
-      }
+				led_off(LED_GREEN);
+				led_on(LED_RED);
+			}
 
       toggle_yellow_led();
     }
diff --git a/stm32_driver/ecdsa_model.h b/stm32_driver/ecdsa_model.h
deleted file mode 100644
index 620c56e..0000000
--- a/stm32_driver/ecdsa_model.h
+++ /dev/null
@@ -1,204 +0,0 @@
-//------------------------------------------------------------------------------
-//
-// ecdsa_model.h
-// --------------------------------------------
-// Base point scalar multiplier model for ECDSA
-//
-// Authors: Pavel Shatov
-//
-// Copyright (c) 2015-2016, NORDUnet A/S
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// - Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-//
-// - 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.
-//
-// - Neither the name of the NORDUnet nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// 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 HOLDER 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.
-//
-//------------------------------------------------------------------------------
-
-
-//------------------------------------------------------------------------------
-//
-// Curve Selection
-//
-// USE_CURVE == 1  -> P-256
-// USE_CURVE == 2  -> P-384
-//
-//------------------------------------------------------------------------------
-
-
-//------------------------------------------------------------------------------
-// Model Parameters
-//------------------------------------------------------------------------------
-#if USE_CURVE == 1
-#define OPERAND_WIDTH	(256)	// largest supported operand width in bits
-#elif USE_CURVE == 2
-#define OPERAND_WIDTH	(384)	// largest supported operand width in bits
-#else
-#error USE_CURVE must be either 1 or 2!
-#endif
-
-
-//------------------------------------------------------------------------------
-// P-256 Parameters and Test Vectors
-//------------------------------------------------------------------------------
-
-/* Field Size */
-#define P_256_Q			{0xffffffff, 0x00000001, 0x00000000, 0x00000000, 0x00000000, 0xffffffff, 0xffffffff, 0xffffffff}
-
-/* Generic Numbers */
-#define P_256_ZERO		{0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000}
-#define P_256_ONE		{0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000001}
-
-/* Division Factor  */
-#define P_256_DELTA		{0x7fffffff, 0x80000000, 0x80000000, 0x00000000, 0x00000000, 0x80000000, 0x00000000, 0x00000000}
-
-/* Base Point */
-#define P_256_G_X		{0x6b17d1f2, 0xe12c4247, 0xf8bce6e5, 0x63a440f2, 0x77037d81, 0x2deb33a0, 0xf4a13945, 0xd898c296}
-#define P_256_G_Y		{0x4fe342e2, 0xfe1a7f9b, 0x8ee7eb4a, 0x7c0f9e16, 0x2bce3357, 0x6b315ece, 0xcbb64068, 0x37bf51f5}
-
-/* Doubled Base Point */
-#define P_256_H_X		{0x29d05c19, 0x3da77b71, 0x0e863235, 0x38b77e1b, 0x11f904fe, 0xa42998be, 0x16bd8d74, 0x4ece7ad0}
-#define P_256_H_Y		{0xb01cbd1c, 0x01e58065, 0x711814b5, 0x83f061e9, 0xd431cca9, 0x94cea131, 0x3449bf97, 0xc840ae07}
-
-/* Base Point Order */
-#define P_256_N			{0xffffffff, 0x00000000, 0xffffffff, 0xffffffff, 0xbce6faad, 0xa7179e84, 0xf3b9cac2, 0xfc632551}
-
-/* Private Key */
-#define P_256_D			{0x70a12c2d, 0xb16845ed, 0x56ff68cf, 0xc21a472b, 0x3f04d7d6, 0x851bf634, 0x9f2d7d5b, 0x3452b38a}
-
-/* Per-message Random Number */
-#define P_256_K			{0x580ec00d, 0x85643433, 0x4cef3f71, 0xecaed496, 0x5b12ae37, 0xfa47055b, 0x1965c7b1, 0x34ee45d0}
-
-/* Public Key */
-#define P_256_Q_X		{0x8101ece4, 0x7464a6ea, 0xd70cf69a, 0x6e2bd3d8, 0x8691a326, 0x2d22cba4, 0xf7635eaf, 0xf26680a8}
-#define P_256_Q_Y		{0xd8a12ba6, 0x1d599235, 0xf67d9cb4, 0xd58f1783, 0xd3ca43e7, 0x8f0a5aba, 0xa6240799, 0x36c0c3a9}
-
-/* Part of Signature */
-#define P_256_R_X		{0x7214bc96, 0x47160bbd, 0x39ff2f80, 0x533f5dc6, 0xddd70ddf, 0x86bb8156, 0x61e805d5, 0xd4e6f27c}
-#define P_256_R_Y		{0x8b81e3e9, 0x77597110, 0xc7cf2633, 0x435b2294, 0xb7264298, 0x7defd3d4, 0x007e1cfc, 0x5df84541}
-
-
-//------------------------------------------------------------------------------
-// P-384 Parameters and Test Vectors
-//------------------------------------------------------------------------------
-
-/* Field Size */
-#define P_384_Q			{0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xfffffffe, 0xffffffff, 0x00000000, 0x00000000, 0xffffffff}
-
-/* Generic Numbers */
-#define P_384_ZERO		{0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000}
-#define P_384_ONE		{0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000001}
-
-/* Division Factor  */
-#define P_384_DELTA		{0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7fffffff, 0x80000000, 0x0000000, 0x080000000}
-
-/* Base Point */
-#define P_384_G_X		{0xaa87ca22, 0xbe8b0537, 0x8eb1c71e, 0xf320ad74, 0x6e1d3b62, 0x8ba79b98, 0x59f741e0, 0x82542a38, 0x5502f25d, 0xbf55296c, 0x3a545e38, 0x72760ab7}
-#define P_384_G_Y		{0x3617de4a, 0x96262c6f, 0x5d9e98bf, 0x9292dc29, 0xf8f41dbd, 0x289a147c, 0xe9da3113, 0xb5f0b8c0, 0x0a60b1ce, 0x1d7e819d, 0x7a431d7c, 0x90ea0e5f}
-
-/* Doubled Base Point */
-#define P_384_H_X		{0xaaf06bba, 0x82e9f590, 0xe29c71c2, 0x19bea517, 0x23c5893a, 0xe8b0c8cf, 0x4c117c3e, 0xfb57ab8d, 0x55fa1b42, 0x8155ad27, 0x8b574391, 0x1b13ea8a}
-#define P_384_H_Y		{0xc9e821b5, 0x69d9d390, 0xa2616740, 0x6d6d23d6, 0x070be242, 0xd765eb83, 0x1625ceec, 0x4a0f473e, 0xf59f4e30, 0xe2817e62, 0x85bce284, 0x6f15f19d}
-
-/* Base Point Order */
-#define P_384_N			{0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xc7634d81, 0xf4372ddf, 0x581a0db2, 0x48b0a77a, 0xecec196a, 0xccc52973}
-
-/* Private Key */
-#define P_384_D			{0xc838b852, 0x53ef8dc7, 0x394fa580, 0x8a518398, 0x1c7deef5, 0xa69ba8f4, 0xf2117ffe, 0xa39cfcd9, 0x0e95f6cb, 0xc854abac, 0xab701d50, 0xc1f3cf24}
-
-/* Per-message Random Number */
-#define P_384_K			{0xdc6b4403, 0x6989a196, 0xe39d1cda, 0xc000812f, 0x4bdd8b2d, 0xb41bb33a, 0xf5137258, 0x5ebd1db6, 0x3f0ce827, 0x5aa1fd45, 0xe2d2a735, 0xf8749359}
-
-/* Public Key */
-#define P_384_Q_X		{0x1fbac8ee, 0xbd0cbf35, 0x640b39ef, 0xe0808dd7, 0x74debff2, 0x0a2a329e, 0x91713baf, 0x7d7f3c3e, 0x81546d88, 0x3730bee7, 0xe48678f8, 0x57b02ca0}
-#define P_384_Q_Y		{0xeb213103, 0xbd68ce34, 0x3365a8a4, 0xc3d4555f, 0xa385f533, 0x0203bdd7, 0x6ffad1f3, 0xaffb9575, 0x1c132007, 0xe1b24035, 0x3cb0a4cf, 0x1693bdf9}
-
-/* Part of Signature */
-#define P_384_R_X		{0xa0c27ec8, 0x93092dea, 0x1e1bd2cc, 0xfed3cf94, 0x5c8134ed, 0x0c9f8131, 0x1a0f4a05, 0x942db8db, 0xed8dd59f, 0x267471d5, 0x462aa14f, 0xe72de856}
-#define P_384_R_Y		{0x85564940, 0x9815bb91, 0x424eaca5, 0xfd76c973, 0x75d575d1, 0x422ec53d, 0x343bd33b, 0x847fdf0c, 0x11569685, 0xb528ab25, 0x49301542, 0x8d7cf72b}
-
-
-//------------------------------------------------------------------------------
-// Parameter and Test Vector Selection
-//------------------------------------------------------------------------------
-#if USE_CURVE == 1
-
-#define ECDSA_Q			P_256_Q
-
-#define ECDSA_ZERO		P_256_ZERO
-#define ECDSA_ONE		P_256_ONE
-
-#define ECDSA_DELTA		P_256_DELTA
-
-#define ECDSA_G_X		P_256_G_X
-#define ECDSA_G_Y		P_256_G_Y
-
-#define ECDSA_H_X		P_256_H_X
-#define ECDSA_H_Y		P_256_H_Y
-
-#define ECDSA_N			P_256_N
-#define ECDSA_D			P_256_D
-#define ECDSA_K			P_256_K
-
-#define ECDSA_Q_X		P_256_Q_X
-#define ECDSA_Q_Y		P_256_Q_Y
-
-#define ECDSA_R_X		P_256_R_X
-#define ECDSA_R_Y		P_256_R_Y
-
-#elif USE_CURVE == 2
-
-#define ECDSA_Q			P_384_Q
-
-#define ECDSA_ZERO		P_384_ZERO
-#define ECDSA_ONE		P_384_ONE
-
-#define ECDSA_DELTA		P_384_DELTA
-
-#define ECDSA_G_X		P_384_G_X
-#define ECDSA_G_Y		P_384_G_Y
-
-#define ECDSA_H_X		P_384_H_X
-#define ECDSA_H_Y		P_384_H_Y
-
-#define ECDSA_N			P_384_N
-#define ECDSA_D			P_384_D
-#define ECDSA_K			P_384_K
-
-#define ECDSA_Q_X		P_384_Q_X
-#define ECDSA_Q_Y		P_384_Q_Y
-
-#define ECDSA_R_X		P_384_R_X
-#define ECDSA_R_Y		P_384_R_Y
-
-#else
-
-#error USE_CURVE must be either 1 or 2!
-
-#endif
-
-
-//------------------------------------------------------------------------------
-// End-of-File
-//------------------------------------------------------------------------------