## OpenJDK / jdk7u / jdk7u-dev / jdk

### view src/share/native/sun/security/ec/impl/ec_naf.c @ 3909:272483f6650b

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7033660: Update copyright year to 2011 on any files changed in 2011
Reviewed-by: dholmes

author | ohair |
---|---|

date | Wed, 06 Apr 2011 22:06:11 -0700 |

parents | 1b5c838b8db8 |

children | b49a0af85821 |

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/* ********************************************************************* * * 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. * * 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): * Stephen Fung <fungstep@hotmail.com>, Sun Microsystems Laboratories * * 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 (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. */ #include "ecl-priv.h" /* Returns 2^e as an integer. This is meant to be used for small powers of * two. */ int ec_twoTo(int e) { int a = 1; int i; for (i = 0; i < e; i++) { a *= 2; } return a; } /* Computes the windowed non-adjacent-form (NAF) of a scalar. Out should * be an array of signed char's to output to, bitsize should be the number * of bits of out, in is the original scalar, and w is the window size. * NAF is discussed in the paper: D. Hankerson, J. Hernandez and A. * Menezes, "Software implementation of elliptic curve cryptography over * binary fields", Proc. CHES 2000. */ mp_err ec_compute_wNAF(signed char *out, int bitsize, const mp_int *in, int w) { mp_int k; mp_err res = MP_OKAY; int i, twowm1, mask; twowm1 = ec_twoTo(w - 1); mask = 2 * twowm1 - 1; MP_DIGITS(&k) = 0; MP_CHECKOK(mp_init_copy(&k, in)); i = 0; /* Compute wNAF form */ while (mp_cmp_z(&k) > 0) { if (mp_isodd(&k)) { out[i] = MP_DIGIT(&k, 0) & mask; if (out[i] >= twowm1) out[i] -= 2 * twowm1; /* Subtract off out[i]. Note mp_sub_d only works with * unsigned digits */ if (out[i] >= 0) { mp_sub_d(&k, out[i], &k); } else { mp_add_d(&k, -(out[i]), &k); } } else { out[i] = 0; } mp_div_2(&k, &k); i++; } /* Zero out the remaining elements of the out array. */ for (; i < bitsize + 1; i++) { out[i] = 0; } CLEANUP: mp_clear(&k); return res; }