3 * Cryptographic challenges
5 * (c) 2005 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Trivial IP Encryption (TrIPE).
12 * TrIPE is free software: you can redistribute it and/or modify it under
13 * the terms of the GNU General Public License as published by the Free
14 * Software Foundation; either version 3 of the License, or (at your
15 * option) any later version.
17 * TrIPE is distributed in the hope that it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
26 /*----- Header files ------------------------------------------------------*/
30 /*----- Static variables --------------------------------------------------*/
32 static bulkchal
*bchal
;
36 /*----- Challenges --------------------------------------------------------*/
38 /* --- @c_genkey@ --- *
44 * Use: Generates a new challenge key.
47 static void c_genkey(void)
49 bulkalgs
*bulk
= master
->algs
.bulk
;
50 if (bchal
&& bchal
->ops
== bulk
->ops
&& oseq
< 0x07ffffff) return;
51 if (bchal
) bchal
->ops
->freechal(bchal
);
52 bchal
= bulk
->ops
->genchal(bulk
);
53 bchal
->ops
= bulk
->ops
;
60 * Arguments: @const void *m@ = pointer to associated message, or null
61 * @size_t msz@ = length of associated message
62 * @buf *b@ = where to put the challenge
64 * Returns: Zero if OK, nonzero on error.
66 * Use: Issues a new challenge.
69 int c_new(const void *m
, size_t msz
, buf
*b
)
77 if (buf_putu32(b
, oseq
) || (t
= buf_get(b
, bchal
->tagsz
)) == 0)
78 { rc
= -1; goto done
; }
79 if (bchal
->ops
->chaltag(bchal
, m
, msz
, oseq
, t
)) { rc
= -1; goto done
; }
81 trace(T_CHAL
, "chal: issuing challenge %lu", (unsigned long)oseq
);
82 if (msz
) trace_block(T_CRYPTO
, "chal: message block", m
, msz
);
83 trace_block(T_CRYPTO
, "chal: challenge block", p
, BCUR(b
) - p
);
91 /* --- @c_check@ --- *
93 * Arguments: @const void *m@ = pointer to associated message, or null
94 * @size_t msz@ = length of associated message
95 * @buf *b@ = where to find the challenge
97 * Returns: Zero if OK, nonzero if it didn't work.
99 * Use: Checks a challenge. On failure, the buffer is broken.
102 int c_check(const void *m
, size_t msz
, buf
*b
)
108 a_warn("CHAL", "impossible-challenge", A_END
);
112 if (buf_getu32(b
, &seq
) || (t
= buf_get(b
, bchal
->tagsz
)) == 0) {
113 a_warn("CHAL", "invalid-challenge", A_END
);
117 trace(T_CHAL
, "chal: checking challenge, seq = %lu", (unsigned long)seq
);
118 if (msz
) trace_block(T_CRYPTO
, "chal: message block", m
, msz
);
119 trace_block(T_CRYPTO
, "chal: check challenge", p
, BCUR(b
) - p
);
121 if (bchal
->ops
->chalvrf(bchal
, m
, msz
, seq
, t
)) {
122 a_warn("CHAL", "incorrect-tag", A_END
);
125 if (seq_check(&iseq
, seq
, "CHAL")) goto fail
;
126 T( trace(T_CHAL
, "chal: challenge ok"); )
134 /*----- That's all, folks -------------------------------------------------*/