3 * Bulk crypto transformations
5 * (c) 2014 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
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * TrIPE 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 General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
31 /*----- Utilities ---------------------------------------------------------*/
33 #define SEQSZ 4 /* Size of sequence number packet */
35 #define TRACE_IV(qiv, ivsz) do { IF_TRACING(T_KEYSET, { \
36 trace_block(T_CRYPTO, "crypto: initialization vector", \
40 #define TRACE_CT(qpk, sz) do { IF_TRACING(T_KEYSET, { \
41 trace_block(T_CRYPTO, "crypto: encrypted packet", (qpk), (sz)); \
44 #define TRACE_MAC(qmac, tagsz) do { IF_TRACING(T_KEYSET, { \
45 trace_block(T_CRYPTO, "crypto: computed MAC", (qmac), (tagsz)); \
48 #define TRACE_MACERR(pmac, tagsz) do { IF_TRACING(T_KEYSET, { \
49 trace(T_KEYSET, "keyset: incorrect MAC: decryption failed"); \
50 trace_block(T_CRYPTO, "crypto: expected MAC", (pmac), (tagsz)); \
53 /*----- Common functionality for generic-composition transforms -----------*/
55 #define CHECK_MAC(h, pmac, tagsz) do { \
57 const octet *_pmac = (pmac); \
58 size_t _tagsz = (tagsz); \
59 octet *_mac = GH_DONE(_h, 0); \
60 int _eq = ct_memeq(_mac, _pmac, _tagsz); \
61 TRACE_MAC(_mac, _tagsz); \
64 TRACE_MACERR(_pmac, _tagsz); \
65 return (KSERR_DECRYPT); \
69 typedef struct gencomp_algs {
70 const gccipher *c; size_t cksz;
71 const gcmac *m; size_t mksz; size_t tagsz;
74 typedef struct gencomp_chal {
76 gmac *m; size_t tagsz;
79 static int gencomp_getalgs(gencomp_algs *a, const algswitch *asw,
80 dstr *e, key_file *kf, key *k)
88 /* --- Symmetric encryption --- */
90 if ((p = key_getattr(kf, k, "cipher")) == 0) p = "blowfish-cbc";
91 if ((a->c = gcipher_byname(p)) == 0) {
92 a_format(e, "unknown-cipher", "%s", p, A_END);
96 /* --- Message authentication --- */
98 if ((p = key_getattr(kf, k, "mac")) != 0) {
101 if ((q = strrchr(d.buf, '/')) != 0)
103 if ((a->m = gmac_byname(d.buf)) == 0) {
104 a_format(e, "unknown-mac", "%s", d.buf, A_END);
108 a->tagsz = a->m->hashsz;
110 n = strtoul(q, &qq, 0);
112 a_format(e, "bad-tag-length-string", "%s", q, A_END);
115 if (n%8 || n/8 > a->m->hashsz) {
116 a_format(e, "bad-tag-length", "%lu", n, A_END);
123 dstr_putf(&d, "%s-hmac", asw->h->name);
124 if ((a->m = gmac_byname(d.buf)) == 0) {
125 a_format(e, "no-hmac-for-hash", "%s", asw->h->name, A_END);
128 a->tagsz = asw->h->hashsz/2;
138 static void gencomp_tracealgs(const gencomp_algs *a)
140 trace(T_CRYPTO, "crypto: cipher = %s", a->c->name);
141 trace(T_CRYPTO, "crypto: mac = %s/%lu",
142 a->m->name, (unsigned long)a->tagsz * 8);
146 static int gencomp_checkalgs(gencomp_algs *a, const algswitch *asw, dstr *e)
148 /* --- Derive the key sizes --- *
150 * Must ensure that we have non-empty keys. This isn't ideal, but it
151 * provides a handy sanity check. Also must be based on a 64- or 128-bit
152 * block cipher or we can't do the data expiry properly.
155 if ((a->cksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
156 a_format(e, "cipher", "%s", a->c->name,
157 "no-key-size", "%lu", (unsigned long)asw->hashsz,
161 if ((a->mksz = keysz(asw->hashsz, a->m->keysz)) == 0) {
162 a_format(e, "mac", "%s", a->m->name,
163 "no-key-size", "%lu", (unsigned long)asw->hashsz,
171 static void gencomp_alginfo(const gencomp_algs *a, admin *adm)
174 "cipher=%s", a->c->name,
175 "cipher-keysz=%lu", (unsigned long)a->cksz,
176 "cipher-blksz=%lu", (unsigned long)a->c->blksz,
179 "mac=%s", a->m->name,
180 "mac-keysz=%lu", (unsigned long)a->mksz,
181 "mac-tagsz=%lu", (unsigned long)a->tagsz,
185 static int gencomp_samealgsp(const gencomp_algs *a, const gencomp_algs *aa)
187 return (a->c == aa->c &&
188 a->m == aa->m && a->tagsz == aa->tagsz);
191 static size_t gencomp_expsz(const gencomp_algs *a)
192 { return (a->c->blksz < 16 ? MEG(64) : MEG(2048)); }
194 static bulkchal *gencomp_genchal(const gencomp_algs *a)
196 gencomp_chal *gc = CREATE(gencomp_chal);
198 rand_get(RAND_GLOBAL, buf_t, a->mksz);
199 gc->m = GM_KEY(a->m, buf_t, a->mksz);
200 gc->_b.tagsz = a->tagsz;
202 trace(T_CHAL, "chal: generated new challenge key");
203 trace_block(T_CRYPTO, "chal: new key", buf_t, a->mksz);
208 static int gencomp_chaltag(bulkchal *bc, const void *m, size_t msz, void *t)
210 gencomp_chal *gc = (gencomp_chal *)bc;
211 ghash *h = GM_INIT(gc->m);
214 memcpy(t, GH_DONE(h, 0), bc->tagsz);
219 static int gencomp_chalvrf(bulkchal *bc, const void *m, size_t msz,
222 gencomp_chal *gc = (gencomp_chal *)bc;
223 ghash *h = GM_INIT(gc->m);
227 ok = ct_memeq(GH_DONE(h, 0), t, gc->_b.tagsz);
229 return (ok ? 0 : -1);
232 static void gencomp_freechal(bulkchal *bc)
233 { gencomp_chal *gc = (gencomp_chal *)bc; GM_DESTROY(gc->m); DESTROY(gc); }
235 /*----- The original transform --------------------------------------------*
237 * We generate a random initialization vector (if the cipher needs one). We
238 * encrypt the input message with the cipher, and format the type, sequence
239 * number, IV, and ciphertext as follows.
241 * +------+ +------+---...---+------...------+
242 * | type | | seq | iv | ciphertext |
243 * +------+ +------+---...---+------...------+
246 * All of this is fed into the MAC to compute a tag. The type is not
247 * transmitted: the other end knows what type of message it expects, and the
248 * type is only here to prevent us from being confused because some other
249 * kind of ciphertext has been substituted. The tag is prepended to the
250 * remainder, to yield the finished cryptogram, as follows.
252 * +---...---+------+---...---+------...------+
253 * | tag | seq | iv | ciphertext |
254 * +---...---+------+---...---+------...------+
257 * Decryption: checks the overall size, verifies the tag, then decrypts the
258 * ciphertext and extracts the sequence number.
261 typedef struct v0_algs {
266 typedef struct v0_ctx {
275 static bulkalgs *v0_getalgs(const algswitch *asw, dstr *e,
276 key_file *kf, key *k)
278 v0_algs *a = CREATE(v0_algs);
279 if (gencomp_getalgs(&a->ga, asw, e, kf, k)) { DESTROY(a); return (0); }
284 static void v0_tracealgs(const bulkalgs *aa)
285 { const v0_algs *a = (const v0_algs *)aa; gencomp_tracealgs(&a->ga); }
288 static int v0_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
290 v0_algs *a = (v0_algs *)aa;
291 if (gencomp_checkalgs(&a->ga, asw, e)) return (-1);
295 static int v0_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
297 const v0_algs *a = (const v0_algs *)aa, *b = (const v0_algs *)bb;
298 return (gencomp_samealgsp(&a->ga, &b->ga));
301 static void v0_alginfo(const bulkalgs *aa, admin *adm)
302 { const v0_algs *a = (const v0_algs *)aa; gencomp_alginfo(&a->ga, adm); }
304 static size_t v0_overhead(const bulkalgs *aa)
306 const v0_algs *a = (const v0_algs *)aa;
307 return (a->ga.tagsz + SEQSZ + a->ga.c->blksz);
310 static size_t v0_expsz(const bulkalgs *aa)
311 { const v0_algs *a = (const v0_algs *)aa; return (gencomp_expsz(&a->ga)); }
313 static bulkctx *v0_genkeys(const bulkalgs *aa, const struct rawkey *rk)
315 const v0_algs *a = (const v0_algs *)aa;
316 v0_ctx *bc = CREATE(v0_ctx);
320 bc->tagsz = a->ga.tagsz;
321 for (i = 0; i < NDIR; i++) {
322 ks_derivekey(k, a->ga.cksz, rk, i, "encryption");
323 bc->d[i].c = GC_INIT(a->ga.c, k, a->ga.cksz);
324 ks_derivekey(k, a->ga.mksz, rk, i, "integrity");
325 bc->d[i].m = GM_KEY(a->ga.m, k, a->ga.mksz);
330 static bulkchal *v0_genchal(const bulkalgs *aa)
332 const v0_algs *a = (const v0_algs *)aa;
333 return (gencomp_genchal(&a->ga));
335 #define v0_chaltag gencomp_chaltag
336 #define v0_chalvrf gencomp_chalvrf
337 #define v0_freechal gencomp_freechal
339 static void v0_freealgs(bulkalgs *aa)
340 { v0_algs *a = (v0_algs *)aa; DESTROY(a); }
342 static void v0_freectx(bulkctx *bbc)
344 v0_ctx *bc = (v0_ctx *)bbc;
347 for (i = 0; i < NDIR; i++) {
348 GC_DESTROY(bc->d[i].c);
349 GM_DESTROY(bc->d[i].m);
354 static int v0_encrypt(bulkctx *bbc, unsigned ty,
355 buf *b, buf *bb, uint32 seq)
357 v0_ctx *bc = (v0_ctx *)bbc;
359 gcipher *c = bc->d[DIR_OUT].c;
360 const octet *p = BCUR(b);
361 size_t sz = BLEFT(b);
362 octet *qmac, *qseq, *qiv, *qpk;
363 size_t ivsz = GC_CLASS(c)->blksz;
364 size_t tagsz = bc->tagsz;
367 /* --- Determine the ciphertext layout --- */
369 if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz)) return (0);
370 qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz;
371 BSTEP(bb, tagsz + SEQSZ + ivsz + sz);
373 /* --- Store the type --- *
375 * This isn't transmitted, but it's covered by the MAC.
380 /* --- Store the sequence number --- */
384 /* --- Establish an initialization vector if necessary --- */
387 rand_get(RAND_GLOBAL, qiv, ivsz);
392 /* --- Encrypt the packet --- */
394 GC_ENCRYPT(c, p, qpk, sz);
397 /* --- Compute a MAC over type, sequence number, IV, and ciphertext --- */
400 h = GM_INIT(bc->d[DIR_OUT].m);
401 GH_HASH(h, t, sizeof(t));
402 GH_HASH(h, qseq, SEQSZ + ivsz + sz);
403 memcpy(qmac, GH_DONE(h, 0), tagsz);
405 TRACE_MAC(qmac, tagsz);
408 /* --- We're done --- */
413 static int v0_decrypt(bulkctx *bbc, unsigned ty,
414 buf *b, buf *bb, uint32 *seq)
416 v0_ctx *bc = (v0_ctx *)bbc;
417 const octet *pmac, *piv, *pseq, *ppk;
418 size_t psz = BLEFT(b);
422 gcipher *c = bc->d[DIR_IN].c;
423 size_t ivsz = GC_CLASS(c)->blksz;
424 size_t tagsz = bc->tagsz;
427 /* --- Break up the packet into its components --- */
429 if (psz < ivsz + SEQSZ + tagsz) {
430 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
431 return (KSERR_MALFORMED);
433 sz = psz - ivsz - SEQSZ - tagsz;
434 pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz;
437 /* --- Verify the MAC on the packet --- */
440 h = GM_INIT(bc->d[DIR_IN].m);
441 GH_HASH(h, t, sizeof(t));
442 GH_HASH(h, pseq, SEQSZ + ivsz + sz);
443 CHECK_MAC(h, pmac, tagsz);
446 /* --- Decrypt the packet --- */
452 GC_DECRYPT(c, ppk, q, sz);
454 /* --- Finished --- */
461 /*----- The implicit-IV transform -----------------------------------------*
463 * The v0 transform makes everything explicit. There's an IV because the
464 * cipher needs an IV; there's a sequence number because replay prevention
465 * needs a sequence number.
467 * This new transform works rather differently. We make use of a block
468 * cipher to encrypt the sequence number, and use that as the IV. We
469 * transmit the sequence number in the clear, as before. This reduces
470 * overhead; and it's not a significant privacy leak because the adversary
471 * can see the order in which the messages are transmitted -- i.e., the
472 * sequence numbers are almost completely predictable anyway.
474 * So, a MAC is computed over
476 * +------+ +------+------...------+
477 * | type | | seq | ciphertext |
478 * +------+ +------+------...------+
481 * and we actually transmit the following as the cryptogram.
483 * +---...---+------+------...------+
484 * | tag | seq | ciphertext |
485 * +---...---+------+------...------+
489 typedef struct iiv_algs {
492 const gccipher *b; size_t bksz;
495 typedef struct iiv_ctx {
505 static bulkalgs *iiv_getalgs(const algswitch *asw, dstr *e,
506 key_file *kf, key *k)
508 iiv_algs *a = CREATE(iiv_algs);
509 dstr d = DSTR_INIT, dd = DSTR_INIT;
513 if (gencomp_getalgs(&a->ga, asw, e, kf, k)) goto fail;
515 if ((p = key_getattr(kf, k, "blkc")) == 0) {
516 dstr_puts(&dd, a->ga.c->name);
517 if ((q = strrchr(dd.buf, '-')) != 0) *q = 0;
520 dstr_putf(&d, "%s-ecb", p);
521 if ((a->b = gcipher_byname(d.buf)) == 0) {
522 a_format(e, "unknown-blkc", "%s", p, A_END);
526 dstr_destroy(&d); dstr_destroy(&dd);
529 dstr_destroy(&d); dstr_destroy(&dd);
535 static void iiv_tracealgs(const bulkalgs *aa)
537 const iiv_algs *a = (const iiv_algs *)aa;
539 gencomp_tracealgs(&a->ga);
540 trace(T_CRYPTO, "crypto: blkc = %.*s", strlen(a->b->name) - 4, a->b->name);
544 static int iiv_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
546 iiv_algs *a = (iiv_algs *)aa;
548 if (gencomp_checkalgs(&a->ga, asw, e)) return (-1);
550 if ((a->bksz = keysz(asw->hashsz, a->b->keysz)) == 0) {
551 a_format(e, "blkc", "%.*s", strlen(a->b->name) - 4, a->b->name,
552 "no-key-size", "%lu", (unsigned long)asw->hashsz,
556 if (a->b->blksz < a->ga.c->blksz) {
557 a_format(e, "blkc", "%.*s", strlen(a->b->name) - 4, a->b->name,
558 "blksz-insufficient", A_END);
564 static int iiv_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
566 const iiv_algs *a = (const iiv_algs *)aa, *b = (const iiv_algs *)bb;
567 return (gencomp_samealgsp(&a->ga, &b->ga) && a->b == b->b);
570 static void iiv_alginfo(const bulkalgs *aa, admin *adm)
572 const iiv_algs *a = (const iiv_algs *)aa;
573 gencomp_alginfo(&a->ga, adm);
575 "blkc=%.*s", strlen(a->b->name) - 4, a->b->name,
576 "blkc-keysz=%lu", (unsigned long)a->bksz,
577 "blkc-blksz=%lu", (unsigned long)a->b->blksz,
581 static size_t iiv_overhead(const bulkalgs *aa)
582 { const iiv_algs *a = (const iiv_algs *)aa; return (a->ga.tagsz + SEQSZ); }
584 static size_t iiv_expsz(const bulkalgs *aa)
586 const iiv_algs *a = (const iiv_algs *)aa;
587 return (gencomp_expsz(&a->ga));
590 static bulkctx *iiv_genkeys(const bulkalgs *aa, const struct rawkey *rk)
592 const iiv_algs *a = (const iiv_algs *)aa;
593 iiv_ctx *bc = CREATE(iiv_ctx);
597 bc->tagsz = a->ga.tagsz;
598 for (i = 0; i < NDIR; i++) {
599 ks_derivekey(k, a->ga.cksz, rk, i, "encryption");
600 bc->d[i].c = GC_INIT(a->ga.c, k, a->ga.cksz);
601 ks_derivekey(k, a->bksz, rk, i, "blkc");
602 bc->d[i].b = GC_INIT(a->b, k, a->bksz);
603 ks_derivekey(k, a->ga.mksz, rk, i, "integrity");
604 bc->d[i].m = GM_KEY(a->ga.m, k, a->ga.mksz);
609 static bulkchal *iiv_genchal(const bulkalgs *aa)
611 const iiv_algs *a = (const iiv_algs *)aa;
612 return (gencomp_genchal(&a->ga));
614 #define iiv_chaltag gencomp_chaltag
615 #define iiv_chalvrf gencomp_chalvrf
616 #define iiv_freechal gencomp_freechal
618 static void iiv_freealgs(bulkalgs *aa)
619 { iiv_algs *a = (iiv_algs *)aa; DESTROY(a); }
621 static void iiv_freectx(bulkctx *bbc)
623 iiv_ctx *bc = (iiv_ctx *)bbc;
626 for (i = 0; i < NDIR; i++) {
627 GC_DESTROY(bc->d[i].c);
628 GC_DESTROY(bc->d[i].b);
629 GM_DESTROY(bc->d[i].m);
634 #define TRACE_PRESEQ(qseq, ivsz) do { IF_TRACING(T_KEYSET, { \
635 trace_block(T_CRYPTO, "crypto: IV derivation input", (qseq), (ivsz)); \
638 static int iiv_encrypt(bulkctx *bbc, unsigned ty,
639 buf *b, buf *bb, uint32 seq)
641 iiv_ctx *bc = (iiv_ctx *)bbc;
643 gcipher *c = bc->d[DIR_OUT].c, *blkc = bc->d[DIR_OUT].b;
644 const octet *p = BCUR(b);
645 size_t sz = BLEFT(b);
646 octet *qmac, *qseq, *qpk;
647 size_t ivsz = GC_CLASS(c)->blksz, blkcsz = GC_CLASS(blkc)->blksz;
648 size_t tagsz = bc->tagsz;
651 /* --- Determine the ciphertext layout --- */
653 if (buf_ensure(bb, tagsz + SEQSZ + sz)) return (0);
654 qmac = BCUR(bb); qseq = qmac + tagsz; qpk = qseq + SEQSZ;
655 BSTEP(bb, tagsz + SEQSZ + sz);
657 /* --- Store the type --- *
659 * This isn't transmitted, but it's covered by the MAC.
664 /* --- Store the sequence number --- */
668 /* --- Establish an initialization vector if necessary --- */
671 memset(buf_u, 0, blkcsz - SEQSZ);
672 memcpy(buf_u + blkcsz - SEQSZ, qseq, SEQSZ);
673 TRACE_PRESEQ(buf_u, ivsz);
674 GC_ENCRYPT(blkc, buf_u, buf_u, blkcsz);
676 TRACE_IV(buf_u, ivsz);
679 /* --- Encrypt the packet --- */
681 GC_ENCRYPT(c, p, qpk, sz);
684 /* --- Compute a MAC over type, sequence number, and ciphertext --- */
687 h = GM_INIT(bc->d[DIR_OUT].m);
688 GH_HASH(h, t, sizeof(t));
689 GH_HASH(h, qseq, SEQSZ + sz);
690 memcpy(qmac, GH_DONE(h, 0), tagsz);
692 TRACE_MAC(qmac, tagsz);
695 /* --- We're done --- */
700 static int iiv_decrypt(bulkctx *bbc, unsigned ty,
701 buf *b, buf *bb, uint32 *seq)
703 iiv_ctx *bc = (iiv_ctx *)bbc;
704 const octet *pmac, *pseq, *ppk;
705 size_t psz = BLEFT(b);
709 gcipher *c = bc->d[DIR_IN].c, *blkc = bc->d[DIR_IN].b;
710 size_t ivsz = GC_CLASS(c)->blksz, blkcsz = GC_CLASS(blkc)->blksz;
711 size_t tagsz = bc->tagsz;
714 /* --- Break up the packet into its components --- */
716 if (psz < SEQSZ + tagsz) {
717 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
718 return (KSERR_MALFORMED);
720 sz = psz - SEQSZ - tagsz;
721 pmac = BCUR(b); pseq = pmac + tagsz; ppk = pseq + SEQSZ;
724 /* --- Verify the MAC on the packet --- */
727 h = GM_INIT(bc->d[DIR_IN].m);
728 GH_HASH(h, t, sizeof(t));
729 GH_HASH(h, pseq, SEQSZ + sz);
730 CHECK_MAC(h, pmac, tagsz);
733 /* --- Decrypt the packet --- */
736 memset(buf_u, 0, blkcsz - SEQSZ);
737 memcpy(buf_u + blkcsz - SEQSZ, pseq, SEQSZ);
738 TRACE_PRESEQ(buf_u, ivsz);
739 GC_ENCRYPT(blkc, buf_u, buf_u, blkcsz);
741 TRACE_IV(buf_u, ivsz);
743 GC_DECRYPT(c, ppk, q, sz);
745 /* --- Finished --- */
752 /*----- The NaCl box transform --------------------------------------------*
754 * This transform is very similar to the NaCl `crypto_secretbox' transform
755 * described in Bernstein, `Cryptography in NaCl', with the difference that,
756 * rather than using XSalsa20, we use either Salsa20/r or ChaChar, because we
757 * have no need of XSalsa20's extended nonce. The default cipher is Salsa20.
759 * Salsa20 and ChaCha accept a 64-bit nonce. The low 32 bits are the
760 * sequence number, and the high 32 bits are the type, both big-endian.
767 * A stream is generated by concatenating the raw output blocks generated
768 * with this nonce and successive counter values starting from zero. The
769 * first 32 bytes of the stream are used as a key for Poly1305: the first 16
770 * bytes are the universal hash key r, and the second 16 bytes are the mask
773 * +------+------+ +------...------+
774 * | r | s | | keystream |
775 * +------+------+ +------...------+
778 * The remainder of the stream is XORed with the incoming plaintext to form a
779 * ciphertext with the same length. The ciphertext (only) is then tagged
780 * using Poly1305. The tag, sequence number, and ciphertext are concatenated
781 * in this order, and transmitted.
784 * +---...---+------+------...------+
785 * | tag | seq | ciphertext |
786 * +---...---+------+------...------+
789 * Note that there is no need to authenticate the type separately, since it
790 * was used to select the cipher nonce, and hence the Poly1305 key. The
791 * Poly1305 tag length is fixed.
794 typedef struct naclbox_algs {
796 const gccipher *c; size_t cksz;
799 typedef struct naclbox_ctx {
801 struct { gcipher *c; } d[NDIR];
805 static bulkalgs *naclbox_getalgs(const algswitch *asw, dstr *e,
806 key_file *kf, key *k)
808 naclbox_algs *a = CREATE(naclbox_algs);
813 /* --- Collect the selected cipher and check that it's supported --- */
815 p = key_getattr(kf, k, "cipher");
816 if (!p || strcmp(p, "salsa20") == 0) a->c = &salsa20;
817 else if (strcmp(p, "salsa20/12") == 0) a->c = &salsa2012;
818 else if (strcmp(p, "salsa20/8") == 0) a->c = &salsa208;
819 else if (strcmp(p, "chacha20") == 0) a->c = &chacha20;
820 else if (strcmp(p, "chacha12") == 0) a->c = &chacha12;
821 else if (strcmp(p, "chacha8") == 0) a->c = &chacha8;
823 a_format(e, "unknown-cipher", "%s", p, A_END);
827 /* --- Collect the selected MAC, and check the tag length --- */
829 p = key_getattr(kf, k, "mac");
832 else if (strncmp(p, "poly1305", 8) != 0 || (p[8] && p[8] != '/')) {
833 a_format(e, "unknown-mac", "%s", p, A_END);
835 } else if (p[8] == '/') {
836 n = strtoul(p + 9, &qq, 0);
838 a_format(e, "bad-tag-length-string", "%s", p + 9, A_END);
842 a_format(e, "bad-tag-length", "%lu", n, A_END);
854 static void naclbox_tracealgs(const bulkalgs *aa)
856 const naclbox_algs *a = (const naclbox_algs *)aa;
858 trace(T_CRYPTO, "crypto: cipher = %s", a->c->name);
859 trace(T_CRYPTO, "crypto: mac = poly1305/128");
863 static int naclbox_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
865 naclbox_algs *a = (naclbox_algs *)aa;
867 if ((a->cksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
868 a_format(e, "cipher", "%s", a->c->name,
869 "no-key-size", "%lu", (unsigned long)asw->hashsz,
876 static int naclbox_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
878 const naclbox_algs *a = (const naclbox_algs *)aa,
879 *b = (const naclbox_algs *)bb;
880 return (a->c == b->c);
883 static void naclbox_alginfo(const bulkalgs *aa, admin *adm)
885 const naclbox_algs *a = (const naclbox_algs *)aa;
886 a_info(adm, "cipher=%s", a->c->name, "cipher-keysz=32", A_END);
887 a_info(adm, "mac=poly1305", "mac-tagsz=16", A_END);
890 static size_t naclbox_overhead(const bulkalgs *aa)
891 { return (POLY1305_TAGSZ + SEQSZ); }
893 static size_t naclbox_expsz(const bulkalgs *aa)
894 { return (MEG(2048)); }
896 static bulkctx *naclbox_genkeys(const bulkalgs *aa, const struct rawkey *rk)
898 const naclbox_algs *a = (const naclbox_algs *)aa;
899 naclbox_ctx *bc = CREATE(naclbox_ctx);
903 for (i = 0; i < NDIR; i++) {
904 ks_derivekey(k, a->cksz, rk, i, "encryption");
905 bc->d[i].c = GC_INIT(a->c, k, a->cksz);
910 typedef struct naclbox_chal {
915 static bulkchal *naclbox_genchal(const bulkalgs *aa)
917 const naclbox_algs *a = (const naclbox_algs *)aa;
918 naclbox_chal *c = CREATE(naclbox_chal);
919 rand_get(RAND_GLOBAL, buf_t, a->cksz);
920 c->c = GC_INIT(a->c, buf_t, a->cksz);
922 trace(T_CHAL, "chal: generated new challenge key");
923 trace_block(T_CRYPTO, "chal: new key", buf_t, a->cksz);
929 static int naclbox_chaltag(bulkchal *bc, const void *m, size_t msz, void *t)
931 naclbox_chal *c = (naclbox_chal *)bc;
932 octet b0[SALSA20_NONCESZ];
933 assert(msz <= sizeof(b0));
934 memcpy(b0, m, msz); memset(b0 + msz, 0, sizeof(b0) - msz);
936 GC_ENCRYPT(c->c, 0, t, c->_b.tagsz);
940 static int naclbox_chalvrf(bulkchal *bc, const void *m, size_t msz,
943 naclbox_chal *c = (naclbox_chal *)bc;
944 octet b0[SALSA20_NONCESZ], b1[16];
945 assert(msz <= sizeof(b0)); assert(c->_b.tagsz <= sizeof(b1));
946 memcpy(b0, m, msz); memset(b0 + msz, 0, sizeof(b0) - msz);
948 GC_ENCRYPT(c->c, 0, b1, c->_b.tagsz);
949 return (ct_memeq(t, b1, c->_b.tagsz) ? 0 : -1);
952 static void naclbox_freechal(bulkchal *bc)
953 { naclbox_chal *c = (naclbox_chal *)bc; GC_DESTROY(c->c); DESTROY(c); }
955 static void naclbox_freealgs(bulkalgs *aa)
956 { naclbox_algs *a = (naclbox_algs *)aa; DESTROY(a); }
958 static void naclbox_freectx(bulkctx *bbc)
960 naclbox_ctx *bc = (naclbox_ctx *)bbc;
963 for (i = 0; i < NDIR; i++) GC_DESTROY(bc->d[i].c);
967 static int naclbox_encrypt(bulkctx *bbc, unsigned ty,
968 buf *b, buf *bb, uint32 seq)
970 naclbox_ctx *bc = (naclbox_ctx *)bbc;
971 gcipher *c = bc->d[DIR_OUT].c;
974 const octet *p = BCUR(b);
975 size_t sz = BLEFT(b);
976 octet *qmac, *qseq, *qpk;
978 /* --- Determine the ciphertext layout --- */
980 if (buf_ensure(bb, POLY1305_TAGSZ + SEQSZ + sz)) return (0);
981 qmac = BCUR(bb); qseq = qmac + POLY1305_TAGSZ; qpk = qseq + SEQSZ;
982 BSTEP(bb, POLY1305_TAGSZ + SEQSZ + sz);
984 /* --- Construct and set the nonce --- */
987 memcpy(buf_u, qseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
989 TRACE_IV(buf_u, SALSA20_NONCESZ);
991 /* --- Determine the MAC key --- */
993 GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
994 poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
995 poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
997 /* --- Encrypt the message --- */
999 GC_ENCRYPT(c, p, qpk, sz);
1002 /* --- Compute the MAC --- */
1004 poly1305_hash(&poly, qpk, sz);
1005 poly1305_done(&poly, qmac);
1006 TRACE_MAC(qmac, POLY1305_TAGSZ);
1008 /* --- We're done --- */
1013 static int naclbox_decrypt(bulkctx *bbc, unsigned ty,
1014 buf *b, buf *bb, uint32 *seq)
1016 naclbox_ctx *bc = (naclbox_ctx *)bbc;
1017 gcipher *c = bc->d[DIR_IN].c;
1020 const octet *pmac, *pseq, *ppk;
1021 size_t psz = BLEFT(b);
1023 octet *q = BCUR(bb);
1025 /* --- Break up the packet into its components --- */
1027 if (psz < SEQSZ + POLY1305_TAGSZ) {
1028 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
1029 return (KSERR_MALFORMED);
1031 sz = psz - SEQSZ - POLY1305_TAGSZ;
1032 pmac = BCUR(b); pseq = pmac + POLY1305_TAGSZ; ppk = pseq + SEQSZ;
1034 /* --- Construct and set the nonce --- */
1036 memcpy(buf_u, pseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
1038 TRACE_IV(buf_u, SALSA20_NONCESZ);
1040 /* --- Determine the MAC key --- */
1042 GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
1043 poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
1044 poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
1046 /* --- Verify the MAC on the packet --- */
1048 poly1305_hash(&poly, ppk, sz);
1049 poly1305_done(&poly, buf_u);
1050 if (!ct_memeq(buf_u, pmac, POLY1305_TAGSZ)) {
1051 TRACE_MACERR(pmac, POLY1305_TAGSZ);
1052 return (KSERR_DECRYPT);
1055 /* --- Decrypt the packet --- */
1057 GC_DECRYPT(c, ppk, q, sz);
1059 /* --- Finished --- */
1061 *seq = LOAD32(pseq);
1066 /*----- Bulk crypto transform table ---------------------------------------*/
1068 const bulkops bulktab[] = {
1072 #define BULK(name, pre) \
1073 { name, pre##_getalgs, T( pre##_tracealgs COMMA ) \
1074 pre##_checkalgs, pre##_samealgsp, \
1075 pre##_alginfo, pre##_overhead, pre##_expsz, \
1076 pre##_genkeys, pre##_genchal, pre##_freealgs, \
1077 pre##_encrypt, pre##_decrypt, pre##_freectx, \
1078 pre##_chaltag, pre##_chalvrf, pre##_freechal }
1082 BULK("naclbox", naclbox),
1088 /*----- That's all, folks -------------------------------------------------*/