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   1 /* -*-c-*-
   2  *
   3  * $Id: pss.h,v 1.1 2000/07/20 20:13:38 mdw Exp $
   4  *
   5  * Probabistic signature scheme
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: pss.h,v $
  33  * Revision 1.1  2000/07/20 20:13:38  mdw
  34  * Added Bellare and Rogaway's PSS encoding for RSA signatures.
  35  *
  36  */
  37
  38 /*----- Notes on PSS ------------------------------------------------------*
  39  *
  40  * Applying PSS before RSA signing renders the construction provably secure,
  41  * in that the difficulty of forging a signature is directly related to the
  42  * difficulty of inverting the RSA function, in the random oracle model.
  43  * This is a good thing.  PSS was designed by Bellare and Rogaway.  This
  44  * particular variant is the one specified in draft 1 of PKCS#1 version 2.1.
  45  *
  46  * Stanford University have a patent claim on PSS, although if (as seems
  47  * likely) PSS is included in IEEE P1363, they'll grant a free world-wide
  48  * licence to use the scheme for signatures with appendix (rather than
  49  * signatures with message recovery).
  50  */
  51
  52 #ifndef CATACOMB_PSS_H
  53 #define CATACOMB_PSS_H
  54
  55 #ifdef __cplusplus
  56   extern "C" {
  57 #endif
  58
  59 /*----- Header files ------------------------------------------------------*/
  60
  61 #include <mLib/bits.h>
  62 #include <mLib/dstr.h>
  63
  64 #ifndef CATACOMB_GCIPHER_H
  65 #  include "gcipher.h"
  66 #endif
  67
  68 #ifndef CATACOMB_GHASH_H
  69 #  include "ghash.h"
  70 #endif
  71
  72 #ifndef CATACOMB_GRAND_H
  73 #  include "grand.h"
  74 #endif
  75
  76 /*----- Data structures ---------------------------------------------------*/
  77
  78 typedef struct pss {
  79   const gccipher *cc;                   /* Cipher class for masking */
  80   const gchash *ch;                     /* Hash class for choosing a seed */
  81   grand *r;                             /* Random number source */
  82   void *salt;                           /* Pointer to the salt */
  83 } pss;
  84
  85 /*----- Functions provided ------------------------------------------------*/
  86
  87 /* --- @pss_presign@ --- *
  88  *
  89  * Arguments:   @pss *pp@ = pointer to PSS parameter block
  90  *
  91  * Returns:     An initialized generic hash context.
  92  *
  93  * Use:         Initializes a hash function for signing with PSS.  A salt is
  94  *              chosen and written into the parameter block.
  95  */
  96
  97 extern ghash *pss_presign(pss */*pp*/);
  98
  99 /* --- @pss_encode@ --- *
 100  *
 101  * Arguments:   @const void *msg@ = pointer to message (hash) data
 102  *              @size_t msz@ = size of message data
 103  *              @void *buf@ = pointer to output buffer
 104  *              @size_t sz@ = size of the output buffer
 105  *              @void *p@ = pointer to PSS parameter block
 106  *
 107  * Returns:     Zero of all went well, negative on failure.
 108  *
 109  * Use:         Implements the operation @EMSA-PSS-ENCODE@, as defined in
 110  *              PKCS#1 v. 2.1 draft 1.
 111  */
 112
 113 extern int pss_encode(const void */*msg*/, size_t /*msz*/,
 114                       void */*buf*/, size_t /*sz*/, void */*p*/);
 115
 116 /* --- @pss_decode@ --- *
 117  *
 118  * Arguments:   @const void *buf@ = pointer to encoded buffer
 119  *              @size_t sz@ = size of the encoded byffer
 120  *              @dstr *d@ = pointer to destination string
 121  *              @void *p@ = pointer to PSS parameter block
 122  *
 123  * Returns:     The length of the output string (hash) if successful,
 124  *              negative on failure.
 125  *
 126  * Use:         Implements most of the operation @EMSA_PSS_VERIFY@, as
 127  *              defined in PCSK#1 v. 2.1 draft 1.  The salt value is filled
 128  *              in ready for hashing of the data to start.
 129  */
 130
 131 extern int pss_decode(const void */*buf*/, size_t /*sz*/,
 132                       dstr */*d*/, void */*p*/);
 133
 134 /* --- @pss_preverify@ --- *
 135  *
 136  * Arguments:   @pss *pp@ = pointer to PSS parameter block
 137  *
 138  * Returns:     An initialized generic hash context.
 139  *
 140  * Use:         Initializes a hash function for use with PSS.  A salt is
 141  *              read from the parameter block, where @pss_decode@ should have
 142  *              left it.
 143  */
 144
 145 extern ghash *pss_presign(pss */*pp*/);
 146
 147 /* --- @pss_done@ --- *
 148  *
 149  * Arguments:   @pss *pp@ = pointer to PSS parameter block
 150  *
 151  * Returns:     ---
 152  *
 153  * Use:         Disposes of a PSS parameter block once it's finished with.
 154  */
 155
 156 extern void pss_done(pss */*pp*/);
 157
 158 /*----- That's all, folks -------------------------------------------------*/
 159
 160 #ifdef __cplusplus
 161   }
 162 #endif
 163
 164 #endif