Use CPP for jpc_p256[kr]1

src/jpc.c

@@ -0,0 +1,195 @@
+/*
+ * jpc.c -- arithmetic on Jacobian projective coordinates.
+ *
+ * Copyright (C) 2011, 2013 Free Software Initiative of Japan
+ * Author: NIIBE Yutaka <gniibe@fsij.org>
+ *
+ * This file is a part of Gnuk, a GnuPG USB Token implementation.
+ *
+ * Gnuk is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Gnuk is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#define CONCAT0(a,b) a##b
+#define CONCAT1(a,b) CONCAT0(a,b)
+#define CONCAT2(a,b,c) CONCAT1(a,b##c)
+#define CONCAT3(a,b,c) CONCAT2(a,b,c)
+
+#define FUNC(func) CONCAT1(func##_,FIELD)
+#define MFNC(func) CONCAT3(mod,FIELD,_##func)
+
+/**
+ * @brief	X = 2 * A
+ *
+ * @param X	Destination JPC
+ * @param A	JPC
+ */
+void
+FUNC(jpc_double) (jpc *X, const jpc *A)
+{
+  bn256 a[1], b[1], c[1], tmp0[1];
+  bn256 *d;
+
+  if (bn256_is_zero (A->z))		/* A is infinite */
+    return;
+
+  d = X->x;
+  MFNC(sqr) (a, A->y);
+  memcpy (b, a, sizeof (bn256));
+  MFNC(mul) (a, a, A->x);
+  MFNC(shift) (a, a, 2);
+
+  MFNC(sqr) (b, b);
+  MFNC(shift) (b, b, 3);
+
+  MFNC(sqr) (tmp0, A->z);
+  MFNC(sub) (c, A->x, tmp0);
+  MFNC(add) (tmp0, tmp0, A->x);
+  MFNC(mul) (tmp0, tmp0, c);
+  MFNC(shift) (c, tmp0, 1);
+  MFNC(add) (c, c, tmp0);
+
+  MFNC(sqr) (d, c);
+  MFNC(shift) (tmp0, a, 1);
+  MFNC(sub) (d, d, tmp0);
+
+  MFNC(mul) (X->z, A->y, A->z);
+  MFNC(shift) (X->z, X->z, 1);
+
+  MFNC(sub) (tmp0, a, d);
+  MFNC(mul) (tmp0, c, tmp0);
+  MFNC(sub) (X->y, tmp0, b);
+}
+
+/**
+ * @brief	X = A + B
+ *
+ * @param X	Destination JPC
+ * @param A	JPC
+ * @param B	AC
+ * @param MINUS if 1 subtraction, addition otherwise.
+ */
+void
+FUNC(jpc_add_ac_signed) (jpc *X, const jpc *A, const ac *B, int minus)
+{
+  bn256 a[1], b[1], c[1], d[1], tmp[1];
+#define minus_B_y c
+#define c_sqr a
+#define c_cube b
+#define x1_c_sqr c
+#define x1_c_sqr_2 c
+#define c_cube_plus_x1_c_sqr_2 c
+#define x1_c_sqr_copy a
+#define y3_tmp c
+#define y1_c_cube a
+
+  if (bn256_is_zero (A->z))		/* A is infinite */
+    {
+      memcpy (X->x, B->x, sizeof (bn256));
+      if (minus)
+	{
+	  memcpy (tmp, B->y, sizeof (bn256));
+	  bn256_sub (X->y, CONST_P256, B->y);
+	}
+      else
+	{
+	  memcpy (X->y, B->y, sizeof (bn256));
+	  bn256_sub (tmp, CONST_P256, B->y);
+	}
+      memset (X->z, 0, sizeof (bn256));
+      X->z->word[0] = 1;
+      return;
+    }
+
+  MFNC(sqr) (a, A->z);
+  memcpy (b, a, sizeof (bn256));
+  MFNC(mul) (a, a, B->x);
+
+  MFNC(mul) (b, b, A->z);
+  if (minus)
+    {
+      bn256_sub (minus_B_y, CONST_P256, B->y);
+      MFNC(mul) (b, b, minus_B_y);
+    }
+  else
+    {
+      bn256_sub (tmp, CONST_P256, B->y);
+      MFNC(mul) (b, b, B->y);
+    }
+
+  if (bn256_cmp (A->x, a) == 0 && bn256_cmp (A->y, b) == 0)
+    {
+      FUNC(jpc_double) (X, A);
+      return;
+    }
+
+  MFNC(sub) (c, a, A->x);
+  MFNC(sub) (d, b, A->y);
+
+  MFNC(mul) (X->z, A->z, c);
+
+  MFNC(sqr) (c_sqr, c);
+  MFNC(mul) (c_cube, c_sqr, c);
+
+  MFNC(mul) (x1_c_sqr, A->x, c_sqr);
+
+  MFNC(sqr) (X->x, d);
+  memcpy (x1_c_sqr_copy, x1_c_sqr, sizeof (bn256));
+  MFNC(shift) (x1_c_sqr_2, x1_c_sqr, 1);
+  MFNC(add) (c_cube_plus_x1_c_sqr_2, x1_c_sqr_2, c_cube);
+  MFNC(sub) (X->x, X->x, c_cube_plus_x1_c_sqr_2);
+
+  MFNC(sub) (y3_tmp, x1_c_sqr_copy, X->x);
+  MFNC(mul) (y3_tmp, y3_tmp, d);
+  MFNC(mul) (y1_c_cube, A->y, c_cube);
+  MFNC(sub) (X->y, y3_tmp, y1_c_cube);
+}
+
+/**
+ * @brief	X = A + B
+ *
+ * @param X	Destination JPC
+ * @param A	JPC
+ * @param B	AC
+ */
+void
+FUNC(jpc_add_ac) (jpc *X, const jpc *A, const ac *B)
+{
+  FUNC(jpc_add_ac_signed) (X, A, B, 0);
+}
+
+/**
+ * @brief	X = convert A
+ *
+ * @param X	Destination AC
+ * @param A	JPC
+ *
+ * Return -1 on error (infinite).
+ * Return 0 on success.
+ */
+int
+FUNC(jpc_to_ac) (ac *X, const jpc *A)
+{
+  bn256 z_inv[1], z_inv_sqr[1];
+
+  if (MFNC(inv) (z_inv, A->z) < 0)
+    return -1;
+
+  MFNC(sqr) (z_inv_sqr, z_inv);
+  MFNC(mul) (z_inv, z_inv, z_inv_sqr);
+
+  MFNC(mul) (X->x, A->x, z_inv_sqr);
+  MFNC(mul) (X->y, A->y, z_inv);
+  return 0;
+}