jdk/src/share/native/sun/security/ec/ecp_521.c
changeset 3492 e549cea58864
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/native/sun/security/ec/ecp_521.c	Tue Aug 11 16:52:26 2009 +0100
@@ -0,0 +1,192 @@
+/* *********************************************************************
+ *
+ * Sun elects to have this file available under and governed by the
+ * Mozilla Public License Version 1.1 ("MPL") (see
+ * http://www.mozilla.org/MPL/ for full license text). For the avoidance
+ * of doubt and subject to the following, Sun also elects to allow
+ * licensees to use this file under the MPL, the GNU General Public
+ * License version 2 only or the Lesser General Public License version
+ * 2.1 only. Any references to the "GNU General Public License version 2
+ * or later" or "GPL" in the following shall be construed to mean the
+ * GNU General Public License version 2 only. Any references to the "GNU
+ * Lesser General Public License version 2.1 or later" or "LGPL" in the
+ * following shall be construed to mean the GNU Lesser General Public
+ * License version 2.1 only. However, the following notice accompanied
+ * the original version of this file:
+ *
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the elliptic curve math library for prime field curves.
+ *
+ * The Initial Developer of the Original Code is
+ * Sun Microsystems, Inc.
+ * Portions created by the Initial Developer are Copyright (C) 2003
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Douglas Stebila <douglas@stebila.ca>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ *********************************************************************** */
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident   "%Z%%M% %I%     %E% SMI"
+
+#include "ecp.h"
+#include "mpi.h"
+#include "mplogic.h"
+#include "mpi-priv.h"
+#ifndef _KERNEL
+#include <stdlib.h>
+#endif
+
+#define ECP521_DIGITS ECL_CURVE_DIGITS(521)
+
+/* Fast modular reduction for p521 = 2^521 - 1.  a can be r. Uses
+ * algorithm 2.31 from Hankerson, Menezes, Vanstone. Guide to
+ * Elliptic Curve Cryptography. */
+mp_err
+ec_GFp_nistp521_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
+{
+        mp_err res = MP_OKAY;
+        int a_bits = mpl_significant_bits(a);
+        int i;
+
+        /* m1, m2 are statically-allocated mp_int of exactly the size we need */
+        mp_int m1;
+
+        mp_digit s1[ECP521_DIGITS] = { 0 };
+
+        MP_SIGN(&m1) = MP_ZPOS;
+        MP_ALLOC(&m1) = ECP521_DIGITS;
+        MP_USED(&m1) = ECP521_DIGITS;
+        MP_DIGITS(&m1) = s1;
+
+        if (a_bits < 521) {
+                if (a==r) return MP_OKAY;
+                return mp_copy(a, r);
+        }
+        /* for polynomials larger than twice the field size or polynomials
+         * not using all words, use regular reduction */
+        if (a_bits > (521*2)) {
+                MP_CHECKOK(mp_mod(a, &meth->irr, r));
+        } else {
+#define FIRST_DIGIT (ECP521_DIGITS-1)
+                for (i = FIRST_DIGIT; i < MP_USED(a)-1; i++) {
+                        s1[i-FIRST_DIGIT] = (MP_DIGIT(a, i) >> 9)
+                                | (MP_DIGIT(a, 1+i) << (MP_DIGIT_BIT-9));
+                }
+                s1[i-FIRST_DIGIT] = MP_DIGIT(a, i) >> 9;
+
+                if ( a != r ) {
+                        MP_CHECKOK(s_mp_pad(r,ECP521_DIGITS));
+                        for (i = 0; i < ECP521_DIGITS; i++) {
+                                MP_DIGIT(r,i) = MP_DIGIT(a, i);
+                        }
+                }
+                MP_USED(r) = ECP521_DIGITS;
+                MP_DIGIT(r,FIRST_DIGIT) &=  0x1FF;
+
+                MP_CHECKOK(s_mp_add(r, &m1));
+                if (MP_DIGIT(r, FIRST_DIGIT) & 0x200) {
+                        MP_CHECKOK(s_mp_add_d(r,1));
+                        MP_DIGIT(r,FIRST_DIGIT) &=  0x1FF;
+                }
+                s_mp_clamp(r);
+        }
+
+  CLEANUP:
+        return res;
+}
+
+/* Compute the square of polynomial a, reduce modulo p521. Store the
+ * result in r.  r could be a.  Uses optimized modular reduction for p521.
+ */
+mp_err
+ec_GFp_nistp521_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
+{
+        mp_err res = MP_OKAY;
+
+        MP_CHECKOK(mp_sqr(a, r));
+        MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth));
+  CLEANUP:
+        return res;
+}
+
+/* Compute the product of two polynomials a and b, reduce modulo p521.
+ * Store the result in r.  r could be a or b; a could be b.  Uses
+ * optimized modular reduction for p521. */
+mp_err
+ec_GFp_nistp521_mul(const mp_int *a, const mp_int *b, mp_int *r,
+                                        const GFMethod *meth)
+{
+        mp_err res = MP_OKAY;
+
+        MP_CHECKOK(mp_mul(a, b, r));
+        MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth));
+  CLEANUP:
+        return res;
+}
+
+/* Divides two field elements. If a is NULL, then returns the inverse of
+ * b. */
+mp_err
+ec_GFp_nistp521_div(const mp_int *a, const mp_int *b, mp_int *r,
+                   const GFMethod *meth)
+{
+        mp_err res = MP_OKAY;
+        mp_int t;
+
+        /* If a is NULL, then return the inverse of b, otherwise return a/b. */
+        if (a == NULL) {
+                return mp_invmod(b, &meth->irr, r);
+        } else {
+                /* MPI doesn't support divmod, so we implement it using invmod and
+                 * mulmod. */
+                MP_CHECKOK(mp_init(&t, FLAG(b)));
+                MP_CHECKOK(mp_invmod(b, &meth->irr, &t));
+                MP_CHECKOK(mp_mul(a, &t, r));
+                MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth));
+          CLEANUP:
+                mp_clear(&t);
+                return res;
+        }
+}
+
+/* Wire in fast field arithmetic and precomputation of base point for
+ * named curves. */
+mp_err
+ec_group_set_gfp521(ECGroup *group, ECCurveName name)
+{
+        if (name == ECCurve_NIST_P521) {
+                group->meth->field_mod = &ec_GFp_nistp521_mod;
+                group->meth->field_mul = &ec_GFp_nistp521_mul;
+                group->meth->field_sqr = &ec_GFp_nistp521_sqr;
+                group->meth->field_div = &ec_GFp_nistp521_div;
+        }
+        return MP_OKAY;
+}