148 lines
4.5 KiB
C
148 lines
4.5 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002 Virtual Unlimited B.V.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/*!\file elgamal.h
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* \brief ElGamal algorithm.
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*
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* For more information on this algorithm, see:
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* "Handbook of Applied Cryptography",
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* 11.5.2: "The ElGamal signature scheme", p. 454-459
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*
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* Two of the signature variants in Note 11.70 are implemented.
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*
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* \todo Implement ElGamal encryption and decryption.
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*
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* \todo Explore the possibility of using simultaneous multiple exponentiation,
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* as described in HAC, 14.87 (iii).
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*
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* \author Bob Deblier <bob.deblier@pandora.be>
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* \ingroup DL_m DL_elgamal_m
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*/
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#ifndef _ELGAMAL_H
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#define _ELGAMAL_H
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#include "mpbarrett.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* The raw ElGamal signing funcion, variant 1.
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*
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* Signing equations:
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*
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* \li \f$r=g^{k}\ \textrm{mod}\ p\f$
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* \li \f$s=k^{-1}(h(m)-xr)\ \textrm{mod}\ (p-1)\f$
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*
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* @param p The prime.
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* @param n The reducer mod (p-1).
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* @param g The generator.
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* @param rgc The pseudo-random generator.
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* @param hm The hash to be signed.
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* @param x The private key value.
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* @param r The signature's \e r value.
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* @param s The signature's \e r value.
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* @retval 0 on success, -1 on failure.
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*/
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BEECRYPTAPI /*@unused@*/
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int elgv1sign(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, randomGeneratorContext* rgc, const mpnumber* hm, const mpnumber* x, mpnumber* r, mpnumber* s)
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/*@modifies r, s */;
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/**
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* The raw ElGamal signing funcion, variant 3.
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*
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* Signing equations:
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*
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* \li \f$r=g^{k}\ \textrm{mod}\ p\f$
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* \li \f$s=xr+kh(m)\ \textrm{mod}\ (p-1)\f$
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*
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* @param p The prime.
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* @param n The reducer mod (p-1).
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* @param g The generator.
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* @param rgc The pseudo-random generator.
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* @param hm The hash to be signed.
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* @param x The private key value.
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* @param r The signature's \e r value.
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* @param s The signature's \e r value.
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* @retval 0 on success, -1 on failure.
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*/
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BEECRYPTAPI /*@unused@*/
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int elgv3sign(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, randomGeneratorContext* rgc, const mpnumber* hm, const mpnumber* x, mpnumber* r, mpnumber* s)
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/*@modifies r, s */;
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/**
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* The raw ElGamal verification funcion, variant 1.
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*
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* Verifying equations:
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*
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* \li Check \f$0<r<p\f$ and \f$0<s<(p-1)\f$
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* \li \f$v_1=y^{r}r^{s}\ \textrm{mod}\ p\f$
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* \li \f$v_2=g^{h(m)}\ \textrm{mod}\ p\f$
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* \li Check \f$v_1=v_2\f$
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*
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* @warning The return type of this function should be a boolean, but since
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* that type isn't as portable, an int is used.
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*
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* @param p The prime.
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* @param n The reducer mod (p-1).
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* @param g The generator.
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* @param hm The hash to be signed.
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* @param y The public key value.
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* @param r The signature's \e r value.
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* @param s The signature's \e r value.
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* @retval 1 on success, 0 on failure.
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*/
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BEECRYPTAPI /*@unused@*/
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int elgv1vrfy(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, const mpnumber* hm, const mpnumber* y, const mpnumber* r, const mpnumber* s)
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/*@*/;
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/**
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* The raw ElGamal verification funcion, variant 3.
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*
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* Verifying equations:
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*
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* \li Check \f$0<r<p\f$ and \f$0<s<(p-1)\f$
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* \li \f$v_1=g^{s}\ \textrm{mod}\ p\f$
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* \li \f$v_2=y^{r}r^{h(m)}\ \textrm{mod}\ p\f$
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* \li Check \f$v_1=v_2\f$
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*
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* @warning The return type of this function should be a boolean, but since
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* that type isn't as portable, an int is used.
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*
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* @param p The prime.
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* @param n The reducer mod (p-1).
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* @param g The generator.
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* @param hm The hash to be signed.
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* @param y The public key value.
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* @param r The signature's \e r value.
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* @param s The signature's \e r value.
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* @retval 1 on success, 0 on failure.
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*/
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BEECRYPTAPI /*@unused@*/
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int elgv3vrfy(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, const mpnumber* hm, const mpnumber* y, const mpnumber* r, const mpnumber* s)
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/*@*/;
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#ifdef __cplusplus
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}
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#endif
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#endif
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