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>
51 #include "blowfish-cbc.h"
52 #include "chacha20-poly1305.h"
59 /*----- Bulk crypto -------------------------------------------------------*/
61 /* --- Authenticated encryption schemes --- */
63 typedef struct aead_encctx
{
67 union { gaead_enc
*enc
; gaead_dec
*dec
; } ed
;
72 static bulk
*aead_internalinit(key
*k
, const gcaead
*aec
)
74 aead_encctx
*ctx
= CREATE(aead_encctx
);
78 if ((ctx
->nsz
= keysz_pad(4, aec
->noncesz
)) == 0)
79 die(EXIT_FAILURE
, "no suitable nonce size for `%s'", aec
->name
);
80 ctx
->tsz
= keysz(0, ctx
->aec
->tagsz
);
85 static bulk
*aead_init(key
*k
, const char *calg
, const char *halg
)
93 if ((q
= key_getattr(0, k
, "cipher")) != 0) calg
= q
;
94 if (!calg
) aec
= &chacha20_poly1305
;
95 else if ((aec
= gaead_byname(calg
)) == 0)
96 die(EXIT_FAILURE
, "AEAD scheme `%s' not found in key `%s'",
100 return (aead_internalinit(k
, aec
));
103 static int aead_commonsetup(aead_encctx
*ctx
, gcipher
*cx
)
107 n
= ksz
= keysz(0, ctx
->aec
->keysz
);
108 if (n
< ctx
->nsz
) n
= ctx
->nsz
;
109 if (n
< ctx
->tsz
) n
= ctx
->tsz
;
112 GC_ENCRYPT(cx
, 0, ctx
->t
, ksz
);
113 ctx
->key
= GAEAD_KEY(ctx
->aec
, ctx
->t
, ksz
);
117 static size_t aead_overhead(bulk
*b
)
118 { aead_encctx
*ctx
= (aead_encctx
*)b
; return (ctx
->aec
->ohd
+ ctx
->tsz
); }
120 static void aead_commondestroy(aead_encctx
*ctx
)
122 if (ctx
->key
) GAEAD_DESTROY(ctx
->key
);
127 static int aead_encsetup(bulk
*b
, gcipher
*cx
)
129 aead_encctx
*ctx
= (aead_encctx
*)b
;
130 ctx
->ed
.enc
= 0; return (aead_commonsetup(ctx
, cx
));
133 static const char *aead_encdoit(bulk
*b
, uint32 seq
, buf
*bb
,
134 const void *p
, size_t sz
)
136 aead_encctx
*ctx
= (aead_encctx
*)b
;
140 memset(ctx
->t
+ 4, 0, ctx
->nsz
- 4); STORE32_B(ctx
->t
, seq
);
142 ctx
->ed
.enc
= GAEAD_ENC(ctx
->key
, ctx
->t
, ctx
->nsz
, 0, sz
, ctx
->tsz
);
144 GAEAD_REINIT(ctx
->ed
.enc
, ctx
->t
, ctx
->nsz
, 0, sz
, ctx
->tsz
);
145 t
= buf_get(bb
, ctx
->tsz
); assert(t
);
146 rc
= GAEAD_ENCRYPT(ctx
->ed
.enc
, p
, sz
, bb
); assert(rc
>= 0);
147 rc
= GAEAD_DONE(ctx
->ed
.enc
, 0, bb
, t
, ctx
->tsz
); assert(rc
>= 0);
151 static void aead_encdestroy(bulk
*b
)
153 aead_encctx
*ctx
= (aead_encctx
*)b
;
154 if (ctx
->ed
.enc
) GAEAD_DESTROY(ctx
->ed
.enc
);
155 aead_commondestroy(ctx
);
158 static int aead_decsetup(bulk
*b
, gcipher
*cx
)
160 aead_encctx
*ctx
= (aead_encctx
*)b
;
161 ctx
->ed
.dec
= 0; return (aead_commonsetup(ctx
, cx
));
164 static const char *aead_decdoit(bulk
*b
, uint32 seq
, buf
*bb
,
165 const void *p
, size_t sz
)
167 aead_encctx
*ctx
= (aead_encctx
*)b
;
172 memset(ctx
->t
+ 4, 0, ctx
->nsz
- 4); STORE32_B(ctx
->t
, seq
);
174 ctx
->ed
.dec
= GAEAD_DEC(ctx
->key
, ctx
->t
, ctx
->nsz
, 0, sz
, ctx
->tsz
);
176 GAEAD_REINIT(ctx
->ed
.enc
, ctx
->t
, ctx
->nsz
, 0, sz
, ctx
->tsz
);
178 buf_init(&bin
, (/*unconst*/ void *)p
, sz
);
179 t
= buf_get(&bin
, ctx
->tsz
); if (!t
) return ("no tag");
180 rc
= GAEAD_DECRYPT(ctx
->ed
.dec
, BCUR(&bin
), BLEFT(&bin
), bb
);
182 rc
= GAEAD_DONE(ctx
->ed
.dec
, 0, bb
, t
, ctx
->tsz
); assert(rc
>= 0);
183 if (!rc
) return ("authentication failure");
187 static void aead_decdestroy(bulk
*b
)
189 aead_encctx
*ctx
= (aead_encctx
*)b
;
190 if (ctx
->ed
.dec
) GAEAD_DESTROY(ctx
->ed
.dec
);
191 aead_commondestroy(ctx
);
194 static const struct bulkops aead_encops
= {
195 aead_init
, aead_encsetup
, aead_overhead
,
196 aead_encdoit
, aead_encdestroy
198 aead_init
, aead_decsetup
, aead_overhead
,
199 aead_decdoit
, aead_decdestroy
202 /* --- NaCl `secretbox' in terms of AEAD --- */
204 static bulk
*naclbox_init(key
*k
, const char *calg
, const char *halg
)
212 if ((q
= key_getattr(0, k
, "cipher")) != 0) calg
= q
;
213 if (!calg
|| strcmp(calg
, "salsa20") == 0) aec
= &salsa20_naclbox
;
214 else if (strcmp(calg
, "salsa20/12") == 0) aec
= &salsa2012_naclbox
;
215 else if (strcmp(calg
, "salsa20/8") == 0) aec
= &salsa208_naclbox
;
216 else if (strcmp(calg
, "chacha20") == 0) aec
= &chacha20_naclbox
;
217 else if (strcmp(calg
, "chacha12") == 0) aec
= &chacha12_naclbox
;
218 else if (strcmp(calg
, "chacha8") == 0) aec
= &chacha8_naclbox
;
221 "unknown or inappropriate encryption scheme `%s' in key `%s'",
226 return (aead_internalinit(k
, aec
));
229 static const bulkops naclbox_encops
= {
230 naclbox_init
, aead_encsetup
, aead_overhead
,
231 aead_encdoit
, aead_encdestroy
232 }, naclbox_decops
= {
233 naclbox_init
, aead_decsetup
, aead_overhead
,
234 aead_decdoit
, aead_decdestroy
237 /* --- Generic composition --- */
239 typedef struct gencomp_encctx
{
245 octet
*t
; size_t tsz
;
248 static bulk
*gencomp_init(key
*k
, const char *calg
, const char *halg
)
250 gencomp_encctx
*ctx
= CREATE(gencomp_encctx
);
252 dstr d
= DSTR_INIT
, t
= DSTR_INIT
;
256 if ((q
= key_getattr(0, k
, "cipher")) != 0) calg
= q
;
257 if (!calg
) ctx
->cc
= &blowfish_cbc
;
258 else if ((ctx
->cc
= gcipher_byname(calg
)) == 0) {
259 die(EXIT_FAILURE
, "encryption scheme `%s' not found in key `%s'",
264 if ((q
= key_getattr(0, k
, "mac")) == 0) {
265 dstr_putf(&d
, "%s-hmac", halg
);
268 if ((ctx
->mc
= gmac_byname(q
)) == 0) {
270 "message authentication code `%s' not found in key `%s'",
277 static int gencomp_setup(bulk
*b
, gcipher
*cx
)
279 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
285 cn
= keysz(0, ctx
->cc
->keysz
); if (cn
> n
) n
= cn
;
286 mn
= keysz(0, ctx
->mc
->keysz
); if (mn
> n
) n
= mn
;
287 ctx
->t
= kd
= xmalloc(n
); ctx
->tsz
= n
;
288 GC_ENCRYPT(cx
, 0, kd
, cn
);
289 ctx
->c
= GC_INIT(ctx
->cc
, kd
, cn
);
290 GC_ENCRYPT(cx
, 0, kd
, mn
);
291 ctx
->m
= GM_KEY(ctx
->mc
, kd
, mn
);
295 static size_t gencomp_overhead(bulk
*b
)
297 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
298 return (ctx
->cc
->blksz
+ ctx
->mc
->hashsz
); }
300 static void gencomp_destroy(bulk
*b
)
302 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
310 static const char *gencomp_encdoit(bulk
*b
, uint32 seq
, buf
*bb
,
311 const void *p
, size_t sz
)
313 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
315 ghash
*h
= GM_INIT(ctx
->m
);
318 if (ctx
->cc
->blksz
) {
319 GC_ENCRYPT(ctx
->cx
, 0, ctx
->t
, ctx
->cc
->blksz
);
320 GC_SETIV(ctx
->c
, ctx
->t
);
322 tag
= buf_get(bb
, ctx
->mc
->hashsz
); assert(tag
);
323 ct
= buf_get(bb
, sz
); assert(ct
);
324 GC_ENCRYPT(ctx
->c
, p
, ct
, sz
);
331 static const char *gencomp_decdoit(bulk
*b
, uint32 seq
, buf
*bb
,
332 const void *p
, size_t sz
)
334 gencomp_encctx
*ctx
= (gencomp_encctx
*)b
;
336 const octet
*tag
, *ct
;
341 buf_init(&bin
, (/*unconst*/ void *)p
, sz
);
342 if ((tag
= buf_get(&bin
, ctx
->mc
->hashsz
)) == 0) return ("no tag");
343 ct
= BCUR(&bin
); sz
= BLEFT(&bin
);
344 pt
= buf_get(bb
, sz
); assert(pt
);
349 ok
= ct_memeq(tag
, GH_DONE(h
, 0), ctx
->mc
->hashsz
);
351 if (!ok
) return ("authentication failure");
353 if (ctx
->cc
->blksz
) {
354 GC_ENCRYPT(ctx
->cx
, 0, ctx
->t
, ctx
->cc
->blksz
);
355 GC_SETIV(ctx
->c
, ctx
->t
);
357 GC_DECRYPT(ctx
->c
, ct
, pt
, sz
);
361 static const bulkops gencomp_encops
= {
362 gencomp_init
, gencomp_setup
, gencomp_overhead
,
363 gencomp_encdoit
, gencomp_destroy
364 }, gencomp_decops
= {
365 gencomp_init
, gencomp_setup
, gencomp_overhead
,
366 gencomp_decdoit
, gencomp_destroy
369 const struct bulktab bulktab
[] = {
370 { "gencomp", &gencomp_encops
, &gencomp_decops
},
371 { "naclbox", &naclbox_encops
, &naclbox_decops
},
372 { "aead", &aead_encops
, &aead_decops
},
376 /*----- Key encapsulation -------------------------------------------------*/
380 typedef struct rsa_encctx
{
385 static kem
*rsa_encinit(key
*k
, void *kd
)
387 rsa_encctx
*re
= CREATE(rsa_encctx
);
388 rsa_pubcreate(&re
->rp
, kd
);
392 static int rsa_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
394 rsa_encctx
*re
= (rsa_encctx
*)k
;
395 mp
*x
= mprand_range(MP_NEW
, re
->rp
.rp
->n
, &rand_global
, 0);
396 mp
*y
= rsa_pubop(&re
->rp
, MP_NEW
, x
);
397 size_t n
= mp_octets(re
->rp
.rp
->n
);
399 mp_storeb(x
, d
->buf
, n
);
400 GH_HASH(h
, d
->buf
, n
);
401 mp_storeb(y
, d
->buf
, n
);
408 static const char *rsa_lengthcheck(mp
*n
)
410 if (mp_bits(n
) < 1020) return ("key too short");
414 static const char *rsa_enccheck(kem
*k
)
416 rsa_encctx
*re
= (rsa_encctx
*)k
;
418 if ((e
= rsa_lengthcheck(re
->rp
.rp
->n
)) != 0) return (e
);
422 static void rsa_encdestroy(kem
*k
)
424 rsa_encctx
*re
= (rsa_encctx
*)k
;
425 rsa_pubdestroy(&re
->rp
);
429 static const kemops rsa_encops
= {
430 rsa_pubfetch
, sizeof(rsa_pub
),
431 rsa_encinit
, rsa_encdoit
, rsa_enccheck
, rsa_encdestroy
434 typedef struct rsa_decctx
{
439 static kem
*rsa_decinit(key
*k
, void *kd
)
441 rsa_decctx
*rd
= CREATE(rsa_decctx
);
442 rsa_privcreate(&rd
->rp
, kd
, &rand_global
);
446 static int rsa_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
448 rsa_decctx
*rd
= (rsa_decctx
*)k
;
449 mp
*x
= mp_loadb(MP_NEW
, d
->buf
, d
->len
);
453 if (MP_CMP(x
, >=, rd
->rp
.rp
->n
)) {
457 n
= mp_octets(rd
->rp
.rp
->n
);
459 x
= rsa_privop(&rd
->rp
, x
, x
);
467 static const char *rsa_deccheck(kem
*k
)
469 rsa_decctx
*rd
= (rsa_decctx
*)k
;
471 if ((e
= rsa_lengthcheck(rd
->rp
.rp
->n
)) != 0) return (e
);
475 static void rsa_decdestroy(kem
*k
)
477 rsa_decctx
*rd
= (rsa_decctx
*)k
;
478 rsa_privdestroy(&rd
->rp
);
482 static const kemops rsa_decops
= {
483 rsa_privfetch
, sizeof(rsa_priv
),
484 rsa_decinit
, rsa_decdoit
, rsa_deccheck
, rsa_decdestroy
487 /* --- DH and EC --- */
489 typedef struct dh_encctx
{
496 static dh_encctx
*dh_doinit(key
*k
, const gprime_param
*gp
, mp
*y
,
497 group
*(*makegroup
)(const gprime_param
*),
500 dh_encctx
*de
= CREATE(dh_encctx
);
504 if ((de
->g
= makegroup(gp
)) == 0)
505 die(EXIT_FAILURE
, "bad %s group in key `%s'", what
, t
.buf
);
507 de
->y
= G_CREATE(de
->g
);
508 if (G_FROMINT(de
->g
, de
->y
, y
))
509 die(EXIT_FAILURE
, "bad public key `%s'", t
.buf
);
514 static dh_encctx
*ec_doinit(key
*k
, const char *cstr
, const ec
*y
)
516 dh_encctx
*de
= CREATE(dh_encctx
);
522 if ((e
= ec_getinfo(&ei
, cstr
)) != 0 ||
523 (de
->g
= group_ec(&ei
)) == 0)
524 die(EXIT_FAILURE
, "bad elliptic curve spec in key `%s': %s", t
.buf
, e
);
526 de
->y
= G_CREATE(de
->g
);
527 if (G_FROMEC(de
->g
, de
->y
, y
))
528 die(EXIT_FAILURE
, "bad public curve point `%s'", t
.buf
);
533 static kem
*dh_encinit(key
*k
, void *kd
)
536 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_prime
, "prime");
540 static kem
*bindh_encinit(key
*k
, void *kd
)
543 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_binary
, "binary");
547 static kem
*ec_encinit(key
*k
, void *kd
)
550 dh_encctx
*de
= ec_doinit(k
, ep
->cstr
, &ep
->p
);
554 static int dh_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
556 dh_encctx
*de
= (dh_encctx
*)k
;
557 mp
*r
= mprand_range(MP_NEW
, de
->g
->r
, &rand_global
, 0);
558 ge
*x
= G_CREATE(de
->g
);
559 ge
*y
= G_CREATE(de
->g
);
560 size_t n
= de
->g
->noctets
;
563 G_EXP(de
->g
, x
, de
->g
->g
, r
);
564 G_EXP(de
->g
, y
, de
->y
, r
);
566 buf_init(&b
, d
->buf
, n
);
567 G_TORAW(de
->g
, &b
, y
);
568 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
569 buf_init(&b
, d
->buf
, n
);
570 G_TORAW(de
->g
, &b
, x
);
571 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
579 static const char *dh_enccheck(kem
*k
)
581 dh_encctx
*de
= (dh_encctx
*)k
;
583 if ((e
= G_CHECK(de
->g
, &rand_global
)) != 0)
585 if (group_check(de
->g
, de
->y
))
586 return ("public key not in subgroup");
590 static void dh_encdestroy(kem
*k
)
592 dh_encctx
*de
= (dh_encctx
*)k
;
593 G_DESTROY(de
->g
, de
->y
);
595 G_DESTROYGROUP(de
->g
);
599 static const kemops dh_encops
= {
600 dh_pubfetch
, sizeof(dh_pub
),
601 dh_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
604 static const kemops bindh_encops
= {
605 dh_pubfetch
, sizeof(dh_pub
),
606 bindh_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
609 static const kemops ec_encops
= {
610 ec_pubfetch
, sizeof(ec_pub
),
611 ec_encinit
, dh_encdoit
, dh_enccheck
, dh_encdestroy
614 static kem
*dh_decinit(key
*k
, void *kd
)
617 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_prime
, "prime");
618 de
->x
= MP_COPY(dp
->x
);
622 static kem
*bindh_decinit(key
*k
, void *kd
)
625 dh_encctx
*de
= dh_doinit(k
, &dp
->dp
, dp
->y
, group_binary
, "binary");
626 de
->x
= MP_COPY(dp
->x
);
630 static kem
*ec_decinit(key
*k
, void *kd
)
633 dh_encctx
*de
= ec_doinit(k
, ep
->cstr
, &ep
->p
);
634 de
->x
= MP_COPY(ep
->x
);
638 static int dh_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
640 dh_encctx
*de
= (dh_encctx
*)k
;
641 ge
*x
= G_CREATE(de
->g
);
642 size_t n
= de
->g
->noctets
;
643 void *p
= xmalloc(n
);
647 buf_init(&b
, d
->buf
, d
->len
);
648 if (G_FROMRAW(de
->g
, &b
, x
) || group_check(de
->g
, x
))
650 G_EXP(de
->g
, x
, x
, de
->x
);
652 G_TORAW(de
->g
, &b
, x
);
653 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
654 GH_HASH(h
, d
->buf
, d
->len
);
662 static const kemops dh_decops
= {
663 dh_privfetch
, sizeof(dh_priv
),
664 dh_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
667 static const kemops bindh_decops
= {
668 dh_privfetch
, sizeof(dh_priv
),
669 bindh_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
672 static const kemops ec_decops
= {
673 ec_privfetch
, sizeof(ec_priv
),
674 ec_decinit
, dh_decdoit
, dh_enccheck
, dh_encdestroy
677 /* --- X25519 and similar schemes --- */
683 #define XDHDEF(xdh, XDH) \
685 static kem *xdh##_encinit(key *k, void *kd) { return (CREATE(kem)); } \
686 static void xdh##_encdestroy(kem *k) { DESTROY(k); } \
688 static const char *xdh##_enccheck(kem *k) \
690 xdh##_pub *kd = k->kd; \
692 if (kd->pub.sz != XDH##_PUBSZ) \
693 return ("incorrect " #XDH "public key length"); \
697 static int xdh##_encdoit(kem *k, dstr *d, ghash *h) \
699 octet t[XDH##_KEYSZ], z[XDH##_OUTSZ]; \
700 xdh##_pub *kd = k->kd; \
702 rand_get(RAND_GLOBAL, t, sizeof(t)); \
703 dstr_ensure(d, XDH##_PUBSZ); \
704 xdh((octet *)d->buf, t, xdh##_base); \
705 xdh(z, t, kd->pub.k); \
706 d->len += XDH##_PUBSZ; \
707 GH_HASH(h, d->buf, XDH##_PUBSZ); \
708 GH_HASH(h, z, XDH##_OUTSZ); \
712 static const char *xdh##_deccheck(kem *k) \
714 xdh##_priv *kd = k->kd; \
716 if (kd->priv.sz != XDH##_KEYSZ) \
717 return ("incorrect " #XDH " private key length"); \
718 if (kd->pub.sz != XDH##_PUBSZ) \
719 return ("incorrect " #XDH " public key length"); \
723 static int xdh##_decdoit(kem *k, dstr *d, ghash *h) \
725 octet z[XDH##_OUTSZ]; \
726 xdh##_priv *kd = k->kd; \
729 if (d->len != XDH##_PUBSZ) goto done; \
730 xdh(z, kd->priv.k, (const octet *)d->buf); \
731 GH_HASH(h, d->buf, XDH##_PUBSZ); \
732 GH_HASH(h, z, XDH##_OUTSZ); \
738 static const kemops xdh##_encops = { \
739 xdh##_pubfetch, sizeof(xdh##_pub), \
740 xdh##_encinit, xdh##_encdoit, xdh##_enccheck, xdh##_encdestroy \
743 static const kemops xdh##_decops = { \
744 xdh##_privfetch, sizeof(xdh##_priv), \
745 xdh##_encinit, xdh##_decdoit, xdh##_deccheck, xdh##_encdestroy \
751 /* --- Symmetric --- */
753 typedef struct symm_ctx
{
759 static kem
*symm_init(key
*k
, void *kd
)
765 s
= CREATE(symm_ctx
);
768 s
->kp
.e
= KENC_BINARY
;
772 if ((err
= key_unpack(&s
->kp
, kd
, &d
)) != 0) {
773 die(EXIT_FAILURE
, "failed to unpack symmetric key `%s': %s",
774 d
.buf
, key_strerror(err
));
780 static int symm_decdoit(kem
*k
, dstr
*d
, ghash
*h
)
782 symm_ctx
*s
= (symm_ctx
*)k
;
784 GH_HASH(h
, s
->kb
.k
, s
->kb
.sz
);
785 GH_HASH(h
, d
->buf
, d
->len
);
789 static int symm_encdoit(kem
*k
, dstr
*d
, ghash
*h
)
791 dstr_ensure(d
, h
->ops
->c
->hashsz
);
792 d
->len
+= h
->ops
->c
->hashsz
;
793 rand_get(RAND_GLOBAL
, d
->buf
, d
->len
);
794 return (symm_decdoit(k
, d
, h
));
797 static const char *symm_check(kem
*k
) { return (0); }
799 static void symm_destroy(kem
*k
)
800 { symm_ctx
*s
= (symm_ctx
*)k
; key_unpackdone(&s
->kp
); }
802 static const kemops symm_encops
= {
804 symm_init
, symm_encdoit
, symm_check
, symm_destroy
807 static const kemops symm_decops
= {
809 symm_init
, symm_decdoit
, symm_check
, symm_destroy
812 /* --- The switch table --- */
814 const struct kemtab kemtab
[] = {
815 { "rsa", &rsa_encops
, &rsa_decops
},
816 { "dh", &dh_encops
, &dh_decops
},
817 { "bindh", &bindh_encops
, &bindh_decops
},
818 { "ec", &ec_encops
, &ec_decops
},
819 #define XDHTAB(xdh, XDH) \
820 { #xdh, &xdh##_encops, &xdh##_decops },
823 { "symm", &symm_encops
, &symm_decops
},
827 /* --- @getkem@ --- *
829 * Arguments: @key *k@ = the key to load
830 * @const char *app@ = application name
831 * @int wantpriv@ = nonzero if we want to decrypt
832 * @bulk **bc@ = bulk crypto context to set up
834 * Returns: A key-encapsulating thing.
839 kem
*getkem(key
*k
, const char *app
, int wantpriv
, bulk
**bc
)
841 const char *kalg
, *halg
= 0, *balg
= 0;
848 const struct kemtab
*kt
;
850 const struct bulktab
*bt
;
856 /* --- Setup stuff --- */
860 /* --- Get the KEM name --- *
862 * Take the attribute if it's there; otherwise use the key type.
866 if ((q
= key_getattr(0, k
, "kem")) != 0) {
869 } else if (strncmp(k
->type
, app
, n
) == 0 && k
->type
[n
] == '-') {
870 dstr_puts(&d
, k
->type
);
873 die(EXIT_FAILURE
, "no KEM for key `%s'", t
.buf
);
876 /* --- Grab the bulk encryption scheme --- *
878 * Grab it from the KEM if it's there, but override it from the attribute.
881 if (p
&& (p
= strchr(p
, '/')) != 0) {
885 if ((q
= key_getattr(0, k
, "bulk")) != 0)
888 /* --- Grab the hash function --- */
890 if (p
&& (p
= strchr(p
, '/')) != 0) {
894 if ((q
= key_getattr(0, k
, "hash")) != 0)
897 /* --- Instantiate the KEM --- */
899 for (kt
= kemtab
; kt
->name
; kt
++) {
900 if (strcmp(kt
->name
, kalg
) == 0)
903 die(EXIT_FAILURE
, "key encapsulation mechanism `%s' not found in key `%s'",
906 ko
= wantpriv ? kt
->decops
: kt
->encops
;
912 kd
= xmalloc(ko
->kdsz
);
913 kp
= key_fetchinit(ko
->kf
, 0, kd
);
914 if ((e
= key_fetch(kp
, k
)) != 0) {
915 die(EXIT_FAILURE
, "error fetching key `%s': %s",
916 t
.buf
, key_strerror(e
));
919 kk
= ko
->init(k
, kd
);
924 /* --- Set up the bulk crypto --- */
928 else if ((kk
->hc
= ghash_byname(halg
)) == 0) {
929 die(EXIT_FAILURE
, "hash algorithm `%s' not found in key `%s'",
936 for (bt
= bulktab
, bo
= 0; bt
->name
; bt
++) {
937 if (strcmp(balg
, bt
->name
) == 0)
938 { balg
= 0; goto b_found
; }
939 n
= strlen(bt
->name
);
940 if (strncmp(balg
, bt
->name
, n
) == 0 && balg
[n
] == '-')
941 { balg
+= n
+ 1; goto b_found
; }
946 bo
= wantpriv ? bt
->decops
: bt
->encops
;
947 *bc
= bo
->init(k
, balg
, kk
->hc
->name
);
951 if ((q
= key_getattr(0, k
, "kdf")) == 0) {
952 dstr_putf(&d
, "%s-mgf", kk
->hc
->name
);
955 if ((kk
->cxc
= gcipher_byname(q
)) == 0) {
956 die(EXIT_FAILURE
, "encryption scheme (KDF) `%s' not found in key `%s'",
960 /* --- Tidy up --- */
967 /* --- @setupkem@ --- *
969 * Arguments: @kem *k@ = key-encapsulation thing
970 * @dstr *d@ = key-encapsulation data
971 * @bulk *bc@ = bulk crypto context to set up
973 * Returns: Zero on success, nonzero on failure.
975 * Use: Initializes all the various symmetric things from a KEM.
978 int setupkem(kem
*k
, dstr
*d
, bulk
*bc
)
986 if (k
->ops
->doit(k
, d
, h
))
988 n
= keysz(GH_CLASS(h
)->hashsz
, k
->cxc
->keysz
);
992 k
->cx
= GC_INIT(k
->cxc
, kd
, n
);
993 bc
->ops
->setup(bc
, k
->cx
);
1001 /* --- @freekem@ --- *
1003 * Arguments: @kem *k@ = key-encapsulation thing
1007 * Use: Frees up a key-encapsulation thing.
1010 void freekem(kem
*k
)
1015 key_fetchdone(k
->kp
);
1022 /*----- That's all, folks -------------------------------------------------*/