3 * Catcrypt key-encapsulation
5 * (c) 2004 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Header files ------------------------------------------------------*/
30 #define _FILE_OFFSET_BITS 64
34 #include <mLib/alloc.h>
35 #include <mLib/dstr.h>
36 #include <mLib/report.h>
50 #include "blowfish-cbc.h"
57 /*----- Bulk crypto -------------------------------------------------------*/
59 /* --- NaCl `secretbox' --- */
61 typedef struct naclbox_encctx
{
67 static bulk
*naclbox_init(key
*k
, const char *calg
, const char *halg
)
69 naclbox_encctx
*ctx
= CREATE(naclbox_encctx
);
75 if ((q
= key_getattr(0, k
, "cipher")) != 0) calg
= q
;
76 if (!calg
|| strcmp(calg
, "salsa20") == 0) ctx
->cc
= &salsa20
;
77 else if (strcmp(calg
, "salsa20/12") == 0) ctx
->cc
= &salsa2012
;
78 else if (strcmp(calg
, "salsa20/8") == 0) ctx
->cc
= &salsa208
;
79 else if (strcmp(calg
, "chacha20") == 0) ctx
->cc
= &chacha20
;
80 else if (strcmp(calg
, "chacha12") == 0) ctx
->cc
= &chacha12
;
81 else if (strcmp(calg
, "chacha8") == 0) ctx
->cc
= &chacha8
;
84 "unknown or inappropriate encryption scheme `%s' in key `%s'",
92 static int naclbox_setup(bulk
*b
, gcipher
*cx
)
94 naclbox_encctx
*ctx
= (naclbox_encctx
*)b
;
95 octet k
[SALSA20_KEYSZ
];
97 GC_ENCRYPT(cx
, 0, k
, sizeof(k
));
98 ctx
->c
= GC_INIT(ctx
->cc
, k
, sizeof(k
));
102 static size_t naclbox_overhead(bulk
*b
) { return (POLY1305_TAGSZ
); }
104 static void naclbox_destroy(bulk
*b
)
106 naclbox_encctx
*ctx
= (naclbox_encctx
*)b
;
112 static const char *naclbox_encdoit(bulk
*b
, uint32 seq
, buf
*bb
,
113 const void *p
, size_t sz
)
115 naclbox_encctx
*ctx
= (naclbox_encctx
*)b
;
121 STORE32(t
, seq
); STORE32(t
+ 4, 0); GC_SETIV(ctx
->c
, t
);
122 GC_ENCRYPT(ctx
->c
, 0, t
, POLY1305_KEYSZ
+ POLY1305_MASKSZ
);
123 poly1305_keyinit(&ak
, t
, POLY1305_KEYSZ
);
124 poly1305_macinit(&a
, &ak
, t
+ POLY1305_KEYSZ
);
126 tag
= buf_get(bb
, POLY1305_TAGSZ
); assert(tag
);
127 ct
= buf_get(bb
, sz
); assert(ct
);
128 GC_ENCRYPT(ctx
->c
, p
, ct
, sz
);
129 poly1305_hash(&a
, ct
, sz
);
130 poly1305_done(&a
, tag
);
134 static const char *naclbox_decdoit(bulk
*b
, uint32 seq
, buf
*bb
,
135 const void *p
, size_t sz
)
137 naclbox_encctx
*ctx
= (naclbox_encctx
*)b
;
142 octet
*tag
, *ct
, *pt
;
144 STORE32(t
, seq
); STORE32(t
+ 4, 0); GC_SETIV(ctx
->c
, t
);
145 GC_ENCRYPT(ctx
->c
, 0, t
, POLY1305_KEYSZ
+ POLY1305_MASKSZ
);
146 poly1305_keyinit(&ak
, t
, POLY1305_KEYSZ
);
147 poly1305_macinit(&a
, &ak
, t
+ POLY1305_KEYSZ
);
149 buf_init(&bin
, (/*unconst*/ void *)p
, sz
);
150 if ((tag
= buf_get(&bin
, POLY1305_TAGSZ
)) == 0) return ("no tag");
151 ct
= BCUR(&bin
); sz
= BLEFT(&bin
);
152 poly1305_hash(&a
, ct
, sz
);
153 poly1305_done(&a
, t
);
154 if (!ct_memeq(t
, tag
, POLY1305_TAGSZ
)) return ("authentication failure");
155 pt
= buf_get(bb
, sz
); assert(pt
);
156 GC_DECRYPT(ctx
->c
, ct
, pt
, sz
);
160 static const bulkops naclbox_encops
= {
161 naclbox_init
, naclbox_setup
, naclbox_overhead
,
162 naclbox_encdoit
, naclbox_destroy
163 }, naclbox_decops
= {
164 naclbox_init
, naclbox_setup
, naclbox_overhead
,
165 naclbox_decdoit
, naclbox_destroy
168 /* --- Generic composition --- */
170 typedef struct gencomp_encctx
{
176 octet
*t
; size_t tsz
;
179 static bulk
*gencomp_init(key
*k
, const char *calg
, const char *halg
)
181 gencomp_encctx
*ctx
= CREATE(gencomp_encctx
);
183 dstr d
= DSTR_INIT
, t
= DSTR_INIT
;
187 if ((q
= key_getattr(0, k
, "cipher")) != 0) calg
= q
;
188 if (!calg
) ctx
->cc
= &blowfish_cbc
;
189 else if ((ctx
->cc
= gcipher_byname(calg
)) == 0) {
190 die(EXIT_FAILURE
, "encryption scheme `%s' not found in key `%s'",
195 if ((q
= key_getattr(0, k
, "mac")) == 0) {
196 dstr_putf(&d
, "%s-hmac", halg
);
199 if ((ctx
->mc
= gmac_byname(q
)) == 0) {
201 "message authentication code `%s' not found in key `%s'",
208 static int gencomp_setup(bulk
*b
, gcipher
*cx
)
210 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
216 cn
= keysz(0, ctx
->cc
->keysz
); if (cn
> n
) n
= cn
;
217 mn
= keysz(0, ctx
->mc
->keysz
); if (mn
> n
) n
= mn
;
218 ctx
->t
= kd
= xmalloc(n
); ctx
->tsz
= n
;
219 GC_ENCRYPT(cx
, 0, kd
, cn
);
220 ctx
->c
= GC_INIT(ctx
->cc
, kd
, cn
);
221 GC_ENCRYPT(cx
, 0, kd
, mn
);
222 ctx
->m
= GM_KEY(ctx
->mc
, kd
, mn
);
226 static size_t gencomp_overhead(bulk
*b
)
228 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
229 return (ctx
->cc
->blksz
+ ctx
->mc
->hashsz
); }
231 static void gencomp_destroy(bulk
*b
)
233 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
241 static const char *gencomp_encdoit(bulk
*b
, uint32 seq
, buf
*bb
,
242 const void *p
, size_t sz
)
244 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
246 ghash
*h
= GM_INIT(ctx
->m
);
249 if (ctx
->cc
->blksz
) {
250 GC_ENCRYPT(ctx
->cx
, 0, ctx
->t
, ctx
->cc
->blksz
);
251 GC_SETIV(ctx
->c
, ctx
->t
);
253 tag
= buf_get(bb
, ctx
->mc
->hashsz
); assert(tag
);
254 ct
= buf_get(bb
, sz
); assert(ct
);
255 GC_ENCRYPT(ctx
->c
, p
, ct
, sz
);
262 static const char *gencomp_decdoit(bulk
*b
, uint32 seq
, buf
*bb
,
263 const void *p
, size_t sz
)
265 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
267 const octet
*tag
, *ct
;
272 buf_init(&bin
, (/*unconst*/ void *)p
, sz
);
273 if ((tag
= buf_get(&bin
, ctx
->mc
->hashsz
)) == 0) return ("no tag");
274 ct
= BCUR(&bin
); sz
= BLEFT(&bin
);
275 pt
= buf_get(bb
, sz
); assert(pt
);
280 ok
= ct_memeq(tag
, GH_DONE(h
, 0), ctx
->mc
->hashsz
);
282 if (!ok
) return ("authentication failure");
284 if (ctx
->cc
->blksz
) {
285 GC_ENCRYPT(ctx
->cx
, 0, ctx
->t
, ctx
->cc
->blksz
);
286 GC_SETIV(ctx
->c
, ctx
->t
);
288 GC_DECRYPT(ctx
->c
, ct
, pt
, sz
);
292 static const bulkops gencomp_encops
= {
293 gencomp_init
, gencomp_setup
, gencomp_overhead
,
294 gencomp_encdoit
, gencomp_destroy
295 }, gencomp_decops
= {
296 gencomp_init
, gencomp_setup
, gencomp_overhead
,
297 gencomp_decdoit
, gencomp_destroy
300 const struct bulktab bulktab
[] = {
301 { "gencomp", &gencomp_encops
, &gencomp_decops
},
302 { "naclbox", &naclbox_encops
, &naclbox_decops
},
306 /*----- Key encapsulation -------------------------------------------------*/
310 typedef struct rsa_encctx
{
315 static kem
*rsa_encinit(key
*k
, void *kd
)
317 rsa_encctx
*re
= CREATE(rsa_encctx
);
318 rsa_pubcreate(&re
->rp
, kd
);
322 static int rsa_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
324 rsa_encctx
*re
= (rsa_encctx
*)k
;
325 mp
*x
= mprand_range(MP_NEW
, re
->rp
.rp
->n
, &rand_global
, 0);
326 mp
*y
= rsa_pubop(&re
->rp
, MP_NEW
, x
);
327 size_t n
= mp_octets(re
->rp
.rp
->n
);
329 mp_storeb(x
, d
->buf
, n
);
330 GH_HASH(h
, d
->buf
, n
);
331 mp_storeb(y
, d
->buf
, n
);
338 static const char *rsa_lengthcheck(mp
*n
)
340 if (mp_bits(n
) < 1020) return ("key too short");
344 static const char *rsa_enccheck(kem
*k
)
346 rsa_encctx
*re
= (rsa_encctx
*)k
;
348 if ((e
= rsa_lengthcheck(re
->rp
.rp
->n
)) != 0) return (e
);
352 static void rsa_encdestroy(kem
*k
)
354 rsa_encctx
*re
= (rsa_encctx
*)k
;
355 rsa_pubdestroy(&re
->rp
);
359 static const kemops rsa_encops
= {
360 rsa_pubfetch
, sizeof(rsa_pub
),
361 rsa_encinit
, rsa_encdoit
, rsa_enccheck
, rsa_encdestroy
364 typedef struct rsa_decctx
{
369 static kem
*rsa_decinit(key
*k
, void *kd
)
371 rsa_decctx
*rd
= CREATE(rsa_decctx
);
372 rsa_privcreate(&rd
->rp
, kd
, &rand_global
);
376 static int rsa_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
378 rsa_decctx
*rd
= (rsa_decctx
*)k
;
379 mp
*x
= mp_loadb(MP_NEW
, d
->buf
, d
->len
);
383 if (MP_CMP(x
, >=, rd
->rp
.rp
->n
)) {
387 n
= mp_octets(rd
->rp
.rp
->n
);
389 x
= rsa_privop(&rd
->rp
, x
, x
);
397 static const char *rsa_deccheck(kem
*k
)
399 rsa_decctx
*rd
= (rsa_decctx
*)k
;
401 if ((e
= rsa_lengthcheck(rd
->rp
.rp
->n
)) != 0) return (e
);
405 static void rsa_decdestroy(kem
*k
)
407 rsa_decctx
*rd
= (rsa_decctx
*)k
;
408 rsa_privdestroy(&rd
->rp
);
412 static const kemops rsa_decops
= {
413 rsa_privfetch
, sizeof(rsa_priv
),
414 rsa_decinit
, rsa_decdoit
, rsa_deccheck
, rsa_decdestroy
417 /* --- DH and EC --- */
419 typedef struct dh_encctx
{
426 static dh_encctx
*dh_doinit(key
*k
, const gprime_param
*gp
, mp
*y
,
427 group
*(*makegroup
)(const gprime_param
*),
430 dh_encctx
*de
= CREATE(dh_encctx
);
434 if ((de
->g
= makegroup(gp
)) == 0)
435 die(EXIT_FAILURE
, "bad %s group in key `%s'", what
, t
.buf
);
437 de
->y
= G_CREATE(de
->g
);
438 if (G_FROMINT(de
->g
, de
->y
, y
))
439 die(EXIT_FAILURE
, "bad public key `%s'", t
.buf
);
444 static dh_encctx
*ec_doinit(key
*k
, const char *cstr
, const ec
*y
)
446 dh_encctx
*de
= CREATE(dh_encctx
);
452 if ((e
= ec_getinfo(&ei
, cstr
)) != 0 ||
453 (de
->g
= group_ec(&ei
)) == 0)
454 die(EXIT_FAILURE
, "bad elliptic curve spec in key `%s': %s", t
.buf
, e
);
456 de
->y
= G_CREATE(de
->g
);
457 if (G_FROMEC(de
->g
, de
->y
, y
))
458 die(EXIT_FAILURE
, "bad public curve point `%s'", t
.buf
);
463 static kem
*dh_encinit(key
*k
, void *kd
)
466 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_prime
, "prime");
470 static kem
*bindh_encinit(key
*k
, void *kd
)
473 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_binary
, "binary");
477 static kem
*ec_encinit(key
*k
, void *kd
)
480 dh_encctx
*de
= ec_doinit(k
, ep
->cstr
, &ep
->p
);
484 static int dh_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
486 dh_encctx
*de
= (dh_encctx
*)k
;
487 mp
*r
= mprand_range(MP_NEW
, de
->g
->r
, &rand_global
, 0);
488 ge
*x
= G_CREATE(de
->g
);
489 ge
*y
= G_CREATE(de
->g
);
490 size_t n
= de
->g
->noctets
;
493 G_EXP(de
->g
, x
, de
->g
->g
, r
);
494 G_EXP(de
->g
, y
, de
->y
, r
);
496 buf_init(&b
, d
->buf
, n
);
497 G_TORAW(de
->g
, &b
, y
);
498 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
499 buf_init(&b
, d
->buf
, n
);
500 G_TORAW(de
->g
, &b
, x
);
501 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
509 static const char *dh_enccheck(kem
*k
)
511 dh_encctx
*de
= (dh_encctx
*)k
;
513 if ((e
= G_CHECK(de
->g
, &rand_global
)) != 0)
515 if (group_check(de
->g
, de
->y
))
516 return ("public key not in subgroup");
520 static void dh_encdestroy(kem
*k
)
522 dh_encctx
*de
= (dh_encctx
*)k
;
523 G_DESTROY(de
->g
, de
->y
);
525 G_DESTROYGROUP(de
->g
);
529 static const kemops dh_encops
= {
530 dh_pubfetch
, sizeof(dh_pub
),
531 dh_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
534 static const kemops bindh_encops
= {
535 dh_pubfetch
, sizeof(dh_pub
),
536 bindh_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
539 static const kemops ec_encops
= {
540 ec_pubfetch
, sizeof(ec_pub
),
541 ec_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
544 static kem
*dh_decinit(key
*k
, void *kd
)
547 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_prime
, "prime");
548 de
->x
= MP_COPY(dp
->x
);
552 static kem
*bindh_decinit(key
*k
, void *kd
)
555 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_binary
, "binary");
556 de
->x
= MP_COPY(dp
->x
);
560 static kem
*ec_decinit(key
*k
, void *kd
)
563 dh_encctx
*de
= ec_doinit(k
, ep
->cstr
, &ep
->p
);
564 de
->x
= MP_COPY(ep
->x
);
568 static int dh_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
570 dh_encctx
*de
= (dh_encctx
*)k
;
571 ge
*x
= G_CREATE(de
->g
);
572 size_t n
= de
->g
->noctets
;
573 void *p
= xmalloc(n
);
577 buf_init(&b
, d
->buf
, d
->len
);
578 if (G_FROMRAW(de
->g
, &b
, x
) || group_check(de
->g
, x
))
580 G_EXP(de
->g
, x
, x
, de
->x
);
582 G_TORAW(de
->g
, &b
, x
);
583 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
584 GH_HASH(h
, d
->buf
, d
->len
);
592 static const kemops dh_decops
= {
593 dh_privfetch
, sizeof(dh_priv
),
594 dh_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
597 static const kemops bindh_decops
= {
598 dh_privfetch
, sizeof(dh_priv
),
599 bindh_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
602 static const kemops ec_decops
= {
603 ec_privfetch
, sizeof(ec_priv
),
604 ec_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
607 /* --- X25519 and similar schemes --- */
613 #define XDHDEF(xdh, XDH) \
615 static kem *xdh##_encinit(key *k, void *kd) { return (CREATE(kem)); } \
616 static void xdh##_encdestroy(kem *k) { DESTROY(k); } \
618 static const char *xdh##_enccheck(kem *k) \
620 xdh##_pub *kd = k->kd; \
622 if (kd->pub.sz != XDH##_PUBSZ) \
623 return ("incorrect " #XDH "public key length"); \
627 static int xdh##_encdoit(kem *k, dstr *d, ghash *h) \
629 octet t[XDH##_KEYSZ], z[XDH##_OUTSZ]; \
630 xdh##_pub *kd = k->kd; \
632 rand_get(RAND_GLOBAL, t, sizeof(t)); \
633 dstr_ensure(d, XDH##_PUBSZ); \
634 xdh((octet *)d->buf, t, xdh##_base); \
635 xdh(z, t, kd->pub.k); \
636 d->len += XDH##_PUBSZ; \
637 GH_HASH(h, d->buf, XDH##_PUBSZ); \
638 GH_HASH(h, z, XDH##_OUTSZ); \
642 static const char *xdh##_deccheck(kem *k) \
644 xdh##_priv *kd = k->kd; \
646 if (kd->priv.sz != XDH##_KEYSZ) \
647 return ("incorrect " #XDH " private key length"); \
648 if (kd->pub.sz != XDH##_PUBSZ) \
649 return ("incorrect " #XDH " public key length"); \
653 static int xdh##_decdoit(kem *k, dstr *d, ghash *h) \
655 octet z[XDH##_OUTSZ]; \
656 xdh##_priv *kd = k->kd; \
659 if (d->len != XDH##_PUBSZ) goto done; \
660 xdh(z, kd->priv.k, (const octet *)d->buf); \
661 GH_HASH(h, d->buf, XDH##_PUBSZ); \
662 GH_HASH(h, z, XDH##_OUTSZ); \
668 static const kemops xdh##_encops = { \
669 xdh##_pubfetch, sizeof(xdh##_pub), \
670 xdh##_encinit, xdh##_encdoit, xdh##_enccheck, xdh##_encdestroy \
673 static const kemops xdh##_decops = { \
674 xdh##_privfetch, sizeof(xdh##_priv), \
675 xdh##_encinit, xdh##_decdoit, xdh##_deccheck, xdh##_encdestroy \
681 /* --- Symmetric --- */
683 typedef struct symm_ctx
{
689 static kem
*symm_init(key
*k
, void *kd
)
695 s
= CREATE(symm_ctx
);
698 s
->kp
.e
= KENC_BINARY
;
702 if ((err
= key_unpack(&s
->kp
, kd
, &d
)) != 0) {
703 die(EXIT_FAILURE
, "failed to unpack symmetric key `%s': %s",
704 d
.buf
, key_strerror(err
));
710 static int symm_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
712 symm_ctx
*s
= (symm_ctx
*)k
;
714 GH_HASH(h
, s
->kb
.k
, s
->kb
.sz
);
715 GH_HASH(h
, d
->buf
, d
->len
);
719 static int symm_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
721 dstr_ensure(d
, h
->ops
->c
->hashsz
);
722 d
->len
+= h
->ops
->c
->hashsz
;
723 rand_get(RAND_GLOBAL
, d
->buf
, d
->len
);
724 return (symm_decdoit(k
, d
, h
));
727 static const char *symm_check(kem
*k
) { return (0); }
729 static void symm_destroy(kem
*k
)
730 { symm_ctx
*s
= (symm_ctx
*)k
; key_unpackdone(&s
->kp
); }
732 static const kemops symm_encops
= {
734 symm_init
, symm_encdoit
, symm_check
, symm_destroy
737 static const kemops symm_decops
= {
739 symm_init
, symm_decdoit
, symm_check
, symm_destroy
742 /* --- The switch table --- */
744 const struct kemtab kemtab
[] = {
745 { "rsa", &rsa_encops
, &rsa_decops
},
746 { "dh", &dh_encops
, &dh_decops
},
747 { "bindh", &bindh_encops
, &bindh_decops
},
748 { "ec", &ec_encops
, &ec_decops
},
749 #define XDHTAB(xdh, XDH) \
750 { #xdh, &xdh##_encops, &xdh##_decops },
753 { "symm", &symm_encops
, &symm_decops
},
757 /* --- @getkem@ --- *
759 * Arguments: @key *k@ = the key to load
760 * @const char *app@ = application name
761 * @int wantpriv@ = nonzero if we want to decrypt
762 * @bulk **bc@ = bulk crypto context to set up
764 * Returns: A key-encapsulating thing.
769 kem
*getkem(key
*k
, const char *app
, int wantpriv
, bulk
**bc
)
771 const char *kalg
, *halg
= 0, *balg
= 0;
778 const struct kemtab
*kt
;
780 const struct bulktab
*bt
;
786 /* --- Setup stuff --- */
790 /* --- Get the KEM name --- *
792 * Take the attribute if it's there; otherwise use the key type.
796 if ((q
= key_getattr(0, k
, "kem")) != 0) {
799 } else if (strncmp(k
->type
, app
, n
) == 0 && k
->type
[n
] == '-') {
800 dstr_puts(&d
, k
->type
);
803 die(EXIT_FAILURE
, "no KEM for key `%s'", t
.buf
);
806 /* --- Grab the bulk encryption scheme --- *
808 * Grab it from the KEM if it's there, but override it from the attribute.
811 if (p
&& (p
= strchr(p
, '/')) != 0) {
815 if ((q
= key_getattr(0, k
, "bulk")) != 0)
818 /* --- Grab the hash function --- */
820 if (p
&& (p
= strchr(p
, '/')) != 0) {
824 if ((q
= key_getattr(0, k
, "hash")) != 0)
827 /* --- Instantiate the KEM --- */
829 for (kt
= kemtab
; kt
->name
; kt
++) {
830 if (strcmp(kt
->name
, kalg
) == 0)
833 die(EXIT_FAILURE
, "key encapsulation mechanism `%s' not found in key `%s'",
836 ko
= wantpriv ? kt
->decops
: kt
->encops
;
842 kd
= xmalloc(ko
->kdsz
);
843 kp
= key_fetchinit(ko
->kf
, 0, kd
);
844 if ((e
= key_fetch(kp
, k
)) != 0) {
845 die(EXIT_FAILURE
, "error fetching key `%s': %s",
846 t
.buf
, key_strerror(e
));
849 kk
= ko
->init(k
, kd
);
854 /* --- Set up the bulk crypto --- */
858 else if ((kk
->hc
= ghash_byname(halg
)) == 0) {
859 die(EXIT_FAILURE
, "hash algorithm `%s' not found in key `%s'",
864 if ((q
= key_getattr(0, k
, "kdf")) == 0) {
865 dstr_putf(&d
, "%s-mgf", kk
->hc
->name
);
868 if ((kk
->cxc
= gcipher_byname(q
)) == 0) {
869 die(EXIT_FAILURE
, "encryption scheme (KDF) `%s' not found in key `%s'",
876 for (bt
= bulktab
, bo
= 0; bt
->name
; bt
++) {
877 if (strcmp(balg
, bt
->name
) == 0)
878 { balg
= 0; goto b_found
; }
879 n
= strlen(bt
->name
);
880 if (strncmp(balg
, bt
->name
, n
) == 0 && balg
[n
] == '-')
881 { balg
+= n
+ 1; goto b_found
; }
886 bo
= wantpriv ? bt
->decops
: bt
->encops
;
887 *bc
= bo
->init(k
, balg
, kk
->hc
->name
);
890 /* --- Tidy up --- */
897 /* --- @setupkem@ --- *
899 * Arguments: @kem *k@ = key-encapsulation thing
900 * @dstr *d@ = key-encapsulation data
901 * @bulk *bc@ = bulk crypto context to set up
903 * Returns: Zero on success, nonzero on failure.
905 * Use: Initializes all the various symmetric things from a KEM.
908 int setupkem(kem
*k
, dstr
*d
, bulk
*bc
)
916 if (k
->ops
->doit(k
, d
, h
))
918 n
= keysz(GH_CLASS(h
)->hashsz
, k
->cxc
->keysz
);
922 k
->cx
= GC_INIT(k
->cxc
, kd
, n
);
923 bc
->ops
->setup(bc
, k
->cx
);
931 /* --- @freekem@ --- *
933 * Arguments: @kem *k@ = key-encapsulation thing
937 * Use: Frees up a key-encapsulation thing.
945 key_fetchdone(k
->kp
);
952 /*----- That's all, folks -------------------------------------------------*/