mdw@git.distorted.org.uk Git - catacomb/blob - symm/modes-test.h

   1 /* -*-c-*-
   2  *
   3  * Common testing for encryption modes
   4  *
   5  * (c) 2018 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software: you can redistribute it and/or modify it
  13  * under the terms of the GNU Library General Public License as published
  14  * by the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb.  If not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  25  * USA.
  26  */
  27
  28 #ifndef CATACOMB_MODES_TEST_H
  29 #define CATACOMB_MODES_TEST_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <mLib/bits.h>
  38
  39 /*----- Data structures ---------------------------------------------------*/
  40
  41 /* Functions used by `test_encmode' below. */
  42 typedef void setupfn(const octet */*k*/, size_t /*ksz*/);
  43 typedef void resetfn(const octet */*iv*/);
  44 typedef void encfn(const octet */*s*/, octet */*d*/, size_t /*sz*/);
  45
  46 /*----- Functions provided ------------------------------------------------*/
  47
  48 #define TEMF_REFALIGN 1u                /* misalignment of pieces affects
  49                                          * the encryption state
  50                                          */
  51
  52 /* --- @test_encmode@ --- *
  53  *
  54  * Arguments:   @const char *name@ = name of the encryption scheme; used to
  55  *                      find the regression-test filename
  56  *              @size_t ksz@ = key size to use, or zero for `don't care'
  57  *              @size_t blksz@ = block size
  58  *              @size_t minsz@ = smallest acceptable buffer size, or 1
  59  *              @unsigned f@ = various additional flags
  60  *              @setupfn *setup@ = key-setup function
  61  *              @resetfn *reset@ = state-reset function
  62  *              @encfn *enc@ = encryption function
  63  *              @decfn *dec@ = decryption function
  64  *              @int argc@ = number of command-line arguments
  65  *              @char *argv@ = pointer to command-line argument vector
  66  *
  67  * Returns:     Zero on success, nonzero to report failure.
  68  *
  69  * Use:         Tests an encryption mode which doesn't have any more formal
  70  *              test vectors.
  71  *
  72  *              The @name@ is used firstly in diagnostic output and secondly
  73  *              to form the default filename to use for regression-test data,
  74  *              as `.../symm/t/modes/NAME.regress'.
  75  *
  76  *              The key size @ksz@ is simply passed on back to the @setup@
  77  *              function, unless the caller passes in zero, in which case
  78  *              @test_encmode@ chooses a key size for itself.
  79  *
  80  *              The block size @blksz@ is used in failure reports, to draw
  81  *              attention to the block structure in the various buffers,
  82  *              which may assist with diagnosis.  It's also used to determine
  83  *              when to apply a consistency check: see below regarding the
  84  *              @TEMF_REFALIGN@ flag.
  85  *
  86  *              The minimum buffer size @minsz@ expresses a limitation on the
  87  *              provided @enc@ and @dec@ functions, that they don't work on
  88  *              inputs smaller than @minsz@; accordingly, @test_encmode@ will
  89  *              not test such small sizes.  This should be 1 if the mode has
  90  *              no limitation.
  91  *
  92  *              The flags @f@ influence testing in various ways explained
  93  *              below.
  94  *
  95  *              The caller-provided functions are assumed to act on some
  96  *              global but hidden state,
  97  *
  98  *                * @setup@ is (currently, at least) called only once, with
  99  *                  the key @k@ and its chosen size @ksz@.
 100  *
 101  *                * @reset@ is called at the start of each encryption or
 102  *                  decryption operation, to program in the initialization
 103  *                  vector to use.  Currently, the same IV is used in all of
 104  *                  the tests, but this might not always be the case.
 105  *
 106  *                * @enc@ is called to encrypt a source buffer @s@ and write
 107  *                  the ciphertext to a destination @d@; @sz@ is the common
 108  *                  size of these buffers.  @d@ might be null, to discard
 109  *                  output; @s@ might be null, to process all-zero input.
 110  *
 111  *                * @dec@ is called to decrypt a source buffer @s@ and write
 112  *                  the recovered plaintext to a destination @d@; @sz@ is the
 113  *                  common size of these buffers.
 114  *
 115  *              Finally, @int argc@ and @char *argv@ are the command-line
 116  *              arguments provided to @main@; @test_encmode@ parses these and
 117  *              alters its behaviour accordingly.
 118  *
 119  *              Currently, @test_encmode@'s tests are built around a single,
 120  *              fairly large, fixed message.  In each test step, the message
 121  *              is split into a number of fragments which are encrypted and
 122  *              decrypted in turn.
 123  *
 124  *              The following tests are performed.
 125  *
 126  *                * The fundamental `round-trip' test, which verifies that
 127  *                  the message can be encrypted and then decrypted
 128  *                  successfully, if the same fragment boundaries are used in
 129  *                  both cases.
 130  *
 131  *                * A `consistency' test.  Some modes, such as CFB, OFB, and
 132  *                  counter, are `resumable': encryption operations are
 133  *                  insensitive to the position of fragment boundaries, so a
 134  *                  single message can be broken into fragments without
 135  *                  affecting the result.  If @TEMF_REFALIGN@ is clear then
 136  *                  the mode under test is verified to have this property.
 137  *                  If @TEMF_REFALIGN' is set, a weaker property is verified:
 138  *                  that encryption is insensitive to the position of
 139  *                  /block-aligned/ fragment boundaries only.
 140  *
 141  *                * A `regression' test, which verifies that the code
 142  *                  produces the same ciphertext as a previous version.  By
 143  *                  setting command-line arguments appropriately, a test
 144  *                  program can be told to record ciphertexts in a (binary)
 145  *                  data file.  Usually, instead, the program will read the
 146  *                  recorded ciphertexts back and verify that it produces the
 147  *                  same data.  For resumable modes, it's only necessary to
 148  *                  record single ciphertext, since all the other ciphertexts
 149  *                  must be equal by consistency; otherwise all non-block-
 150  *                  aligned splits are recorded separately.
 151  */
 152
 153 extern int test_encmode(const char */*name*/,
 154                         size_t /*ksz*/, size_t /*blksz*/,
 155                         size_t /*minsz */, unsigned /*f*/,
 156                         setupfn */*setup*/, resetfn */*reset*/,
 157                         encfn */*enc*/, encfn */*dec*/,
 158                         int /*argc*/, char */*argv*/[]);
 159
 160 /*----- That's all, folks -------------------------------------------------*/
 161
 162 #ifdef __cplusplus
 163   }
 164 #endif
 165
 166 #endif