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 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 /*----- Utilities ---------------------------------------------------------*/
32 #define SEQSZ 4 /* Size of sequence number packet */
34 #define TRACE_IV(qiv, ivsz) do { IF_TRACING(T_KEYSET, { \
35 trace_block(T_CRYPTO, "crypto: initialization vector", \
39 #define TRACE_CT(qpk, sz) do { IF_TRACING(T_KEYSET, { \
40 trace_block(T_CRYPTO, "crypto: encrypted packet", (qpk), (sz)); \
43 #define TRACE_MAC(qmac, tagsz) do { IF_TRACING(T_KEYSET, { \
44 trace_block(T_CRYPTO, "crypto: computed MAC", (qmac), (tagsz)); \
47 #define TRACE_MACERR(pmac, tagsz) do { IF_TRACING(T_KEYSET, { \
48 trace(T_KEYSET, "keyset: incorrect MAC: decryption failed"); \
49 trace_block(T_CRYPTO, "crypto: expected MAC", (pmac), (tagsz)); \
52 /*----- Common functionality for generic-composition transforms -----------*/
54 #define CHECK_MAC(h, pmac, tagsz) do { \
56 const octet *_pmac = (pmac); \
57 size_t _tagsz = (tagsz); \
58 octet *_mac = GH_DONE(_h, 0); \
59 int _eq = ct_memeq(_mac, _pmac, _tagsz); \
60 TRACE_MAC(_mac, _tagsz); \
63 TRACE_MACERR(_pmac, _tagsz); \
64 return (KSERR_DECRYPT); \
68 typedef struct gencomp_algs {
69 const gccipher *c; size_t cksz;
70 const gcmac *m; size_t mksz; size_t tagsz;
73 typedef struct gencomp_chal {
75 gmac *m; size_t tagsz;
78 static int gencomp_getalgs(gencomp_algs *a, const algswitch *asw,
79 dstr *e, key_file *kf, key *k)
87 /* --- Symmetric encryption --- */
89 if ((p = key_getattr(kf, k, "cipher")) == 0) p = "blowfish-cbc";
90 if ((a->c = gcipher_byname(p)) == 0) {
91 a_format(e, "unknown-cipher", "%s", p, A_END);
95 /* --- Message authentication --- */
97 if ((p = key_getattr(kf, k, "mac")) != 0) {
100 if ((q = strrchr(d.buf, '/')) != 0)
102 if ((a->m = gmac_byname(d.buf)) == 0) {
103 a_format(e, "unknown-mac", "%s", d.buf, A_END);
107 a->tagsz = a->m->hashsz;
109 n = strtoul(q, &qq, 0);
111 a_format(e, "bad-tag-length-string", "%s", q, A_END);
114 if (n%8 || n/8 > a->m->hashsz) {
115 a_format(e, "bad-tag-length", "%lu", n, A_END);
122 dstr_putf(&d, "%s-hmac", asw->h->name);
123 if ((a->m = gmac_byname(d.buf)) == 0) {
124 a_format(e, "no-hmac-for-hash", "%s", asw->h->name, A_END);
127 a->tagsz = asw->h->hashsz/2;
137 static void gencomp_tracealgs(const gencomp_algs *a)
139 trace(T_CRYPTO, "crypto: cipher = %s", a->c->name);
140 trace(T_CRYPTO, "crypto: mac = %s/%lu",
141 a->m->name, (unsigned long)a->tagsz * 8);
145 static int gencomp_checkalgs(gencomp_algs *a, const algswitch *asw, dstr *e)
147 /* --- Derive the key sizes --- *
149 * Must ensure that we have non-empty keys. This isn't ideal, but it
150 * provides a handy sanity check. Also must be based on a 64- or 128-bit
151 * block cipher or we can't do the data expiry properly.
154 if ((a->cksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
155 a_format(e, "cipher", "%s", a->c->name,
156 "no-key-size", "%lu", (unsigned long)asw->hashsz,
160 if ((a->mksz = keysz(asw->hashsz, a->m->keysz)) == 0) {
161 a_format(e, "mac", "%s", a->m->name,
162 "no-key-size", "%lu", (unsigned long)asw->hashsz,
170 static void gencomp_alginfo(const gencomp_algs *a, admin *adm)
173 "cipher=%s", a->c->name,
174 "cipher-keysz=%lu", (unsigned long)a->cksz,
175 "cipher-blksz=%lu", (unsigned long)a->c->blksz,
178 "mac=%s", a->m->name,
179 "mac-keysz=%lu", (unsigned long)a->mksz,
180 "mac-tagsz=%lu", (unsigned long)a->tagsz,
184 static int gencomp_samealgsp(const gencomp_algs *a, const gencomp_algs *aa)
186 return (a->c == aa->c &&
187 a->m == aa->m && a->tagsz == aa->tagsz);
190 static size_t gencomp_expsz(const gencomp_algs *a)
191 { return (a->c->blksz < 16 ? MEG(64) : MEG(2048)); }
193 static bulkchal *gencomp_genchal(const gencomp_algs *a)
195 gencomp_chal *gc = CREATE(gencomp_chal);
197 rand_get(RAND_GLOBAL, buf_t, a->mksz);
198 gc->m = GM_KEY(a->m, buf_t, a->mksz);
199 gc->_b.tagsz = a->tagsz;
201 trace(T_CHAL, "chal: generated new challenge key");
202 trace_block(T_CRYPTO, "chal: new key", buf_t, a->mksz);
207 static int gencomp_chaltag(bulkchal *bc, const void *m, size_t msz, void *t)
209 gencomp_chal *gc = (gencomp_chal *)bc;
210 ghash *h = GM_INIT(gc->m);
213 memcpy(t, GH_DONE(h, 0), bc->tagsz);
218 static int gencomp_chalvrf(bulkchal *bc, const void *m, size_t msz,
221 gencomp_chal *gc = (gencomp_chal *)bc;
222 ghash *h = GM_INIT(gc->m);
226 ok = ct_memeq(GH_DONE(h, 0), t, gc->_b.tagsz);
228 return (ok ? 0 : -1);
231 static void gencomp_freechal(bulkchal *bc)
232 { gencomp_chal *gc = (gencomp_chal *)bc; GM_DESTROY(gc->m); DESTROY(gc); }
234 /*----- The original transform --------------------------------------------*
236 * We generate a random initialization vector (if the cipher needs one). We
237 * encrypt the input message with the cipher, and format the type, sequence
238 * number, IV, and ciphertext as follows.
240 * +------+ +------+---...---+------...------+
241 * | type | | seq | iv | ciphertext |
242 * +------+ +------+---...---+------...------+
245 * All of this is fed into the MAC to compute a tag. The type is not
246 * transmitted: the other end knows what type of message it expects, and the
247 * type is only here to prevent us from being confused because some other
248 * kind of ciphertext has been substituted. The tag is prepended to the
249 * remainder, to yield the finished cryptogram, as follows.
251 * +---...---+------+---...---+------...------+
252 * | tag | seq | iv | ciphertext |
253 * +---...---+------+---...---+------...------+
256 * Decryption: checks the overall size, verifies the tag, then decrypts the
257 * ciphertext and extracts the sequence number.
260 typedef struct v0_algs {
265 typedef struct v0_ctx {
274 static bulkalgs *v0_getalgs(const algswitch *asw, dstr *e,
275 key_file *kf, key *k)
277 v0_algs *a = CREATE(v0_algs);
278 if (gencomp_getalgs(&a->ga, asw, e, kf, k)) { DESTROY(a); return (0); }
283 static void v0_tracealgs(const bulkalgs *aa)
284 { const v0_algs *a = (const v0_algs *)aa; gencomp_tracealgs(&a->ga); }
287 static int v0_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
289 v0_algs *a = (v0_algs *)aa;
290 if (gencomp_checkalgs(&a->ga, asw, e)) return (-1);
294 static int v0_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
296 const v0_algs *a = (const v0_algs *)aa, *b = (const v0_algs *)bb;
297 return (gencomp_samealgsp(&a->ga, &b->ga));
300 static void v0_alginfo(const bulkalgs *aa, admin *adm)
301 { const v0_algs *a = (const v0_algs *)aa; gencomp_alginfo(&a->ga, adm); }
303 static size_t v0_overhead(const bulkalgs *aa)
305 const v0_algs *a = (const v0_algs *)aa;
306 return (a->ga.tagsz + SEQSZ + a->ga.c->blksz);
309 static size_t v0_expsz(const bulkalgs *aa)
310 { const v0_algs *a = (const v0_algs *)aa; return (gencomp_expsz(&a->ga)); }
312 static bulkctx *v0_genkeys(const bulkalgs *aa, const struct rawkey *rk)
314 const v0_algs *a = (const v0_algs *)aa;
315 v0_ctx *bc = CREATE(v0_ctx);
319 bc->tagsz = a->ga.tagsz;
320 for (i = 0; i < NDIR; i++) {
321 ks_derivekey(k, a->ga.cksz, rk, i, "encryption");
322 bc->d[i].c = GC_INIT(a->ga.c, k, a->ga.cksz);
323 ks_derivekey(k, a->ga.mksz, rk, i, "integrity");
324 bc->d[i].m = GM_KEY(a->ga.m, k, a->ga.mksz);
329 static bulkchal *v0_genchal(const bulkalgs *aa)
331 const v0_algs *a = (const v0_algs *)aa;
332 return (gencomp_genchal(&a->ga));
334 #define v0_chaltag gencomp_chaltag
335 #define v0_chalvrf gencomp_chalvrf
336 #define v0_freechal gencomp_freechal
338 static void v0_freealgs(bulkalgs *aa)
339 { v0_algs *a = (v0_algs *)aa; DESTROY(a); }
341 static void v0_freectx(bulkctx *bbc)
343 v0_ctx *bc = (v0_ctx *)bbc;
346 for (i = 0; i < NDIR; i++) {
347 GC_DESTROY(bc->d[i].c);
348 GM_DESTROY(bc->d[i].m);
353 static int v0_encrypt(bulkctx *bbc, unsigned ty,
354 buf *b, buf *bb, uint32 seq)
356 v0_ctx *bc = (v0_ctx *)bbc;
358 gcipher *c = bc->d[DIR_OUT].c;
359 const octet *p = BCUR(b);
360 size_t sz = BLEFT(b);
361 octet *qmac, *qseq, *qiv, *qpk;
362 size_t ivsz = GC_CLASS(c)->blksz;
363 size_t tagsz = bc->tagsz;
366 /* --- Determine the ciphertext layout --- */
368 if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz)) return (0);
369 qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz;
370 BSTEP(bb, tagsz + SEQSZ + ivsz + sz);
372 /* --- Store the type --- *
374 * This isn't transmitted, but it's covered by the MAC.
379 /* --- Store the sequence number --- */
383 /* --- Establish an initialization vector if necessary --- */
386 rand_get(RAND_GLOBAL, qiv, ivsz);
391 /* --- Encrypt the packet --- */
393 GC_ENCRYPT(c, p, qpk, sz);
396 /* --- Compute a MAC over type, sequence number, IV, and ciphertext --- */
399 h = GM_INIT(bc->d[DIR_OUT].m);
400 GH_HASH(h, t, sizeof(t));
401 GH_HASH(h, qseq, SEQSZ + ivsz + sz);
402 memcpy(qmac, GH_DONE(h, 0), tagsz);
404 TRACE_MAC(qmac, tagsz);
407 /* --- We're done --- */
412 static int v0_decrypt(bulkctx *bbc, unsigned ty,
413 buf *b, buf *bb, uint32 *seq)
415 v0_ctx *bc = (v0_ctx *)bbc;
416 const octet *pmac, *piv, *pseq, *ppk;
417 size_t psz = BLEFT(b);
421 gcipher *c = bc->d[DIR_IN].c;
422 size_t ivsz = GC_CLASS(c)->blksz;
423 size_t tagsz = bc->tagsz;
426 /* --- Break up the packet into its components --- */
428 if (psz < ivsz + SEQSZ + tagsz) {
429 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
430 return (KSERR_MALFORMED);
432 sz = psz - ivsz - SEQSZ - tagsz;
433 pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz;
436 /* --- Verify the MAC on the packet --- */
439 h = GM_INIT(bc->d[DIR_IN].m);
440 GH_HASH(h, t, sizeof(t));
441 GH_HASH(h, pseq, SEQSZ + ivsz + sz);
442 CHECK_MAC(h, pmac, tagsz);
445 /* --- Decrypt the packet --- */
451 GC_DECRYPT(c, ppk, q, sz);
453 /* --- Finished --- */
460 /*----- The implicit-IV transform -----------------------------------------*
462 * The v0 transform makes everything explicit. There's an IV because the
463 * cipher needs an IV; there's a sequence number because replay prevention
464 * needs a sequence number.
466 * This new transform works rather differently. We make use of a block
467 * cipher to encrypt the sequence number, and use that as the IV. We
468 * transmit the sequence number in the clear, as before. This reduces
469 * overhead; and it's not a significant privacy leak because the adversary
470 * can see the order in which the messages are transmitted -- i.e., the
471 * sequence numbers are almost completely predictable anyway.
473 * So, a MAC is computed over
475 * +------+ +------+------...------+
476 * | type | | seq | ciphertext |
477 * +------+ +------+------...------+
480 * and we actually transmit the following as the cryptogram.
482 * +---...---+------+------...------+
483 * | tag | seq | ciphertext |
484 * +---...---+------+------...------+
488 typedef struct iiv_algs {
491 const gccipher *b; size_t bksz;
494 typedef struct iiv_ctx {
504 static bulkalgs *iiv_getalgs(const algswitch *asw, dstr *e,
505 key_file *kf, key *k)
507 iiv_algs *a = CREATE(iiv_algs);
508 dstr d = DSTR_INIT, dd = DSTR_INIT;
512 if (gencomp_getalgs(&a->ga, asw, e, kf, k)) goto fail;
514 if ((p = key_getattr(kf, k, "blkc")) == 0) {
515 dstr_puts(&dd, a->ga.c->name);
516 if ((q = strrchr(dd.buf, '-')) != 0) *q = 0;
519 dstr_putf(&d, "%s-ecb", p);
520 if ((a->b = gcipher_byname(d.buf)) == 0) {
521 a_format(e, "unknown-blkc", "%s", p, A_END);
525 dstr_destroy(&d); dstr_destroy(&dd);
528 dstr_destroy(&d); dstr_destroy(&dd);
534 static void iiv_tracealgs(const bulkalgs *aa)
536 const iiv_algs *a = (const iiv_algs *)aa;
538 gencomp_tracealgs(&a->ga);
539 trace(T_CRYPTO, "crypto: blkc = %.*s", strlen(a->b->name) - 4, a->b->name);
543 static int iiv_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
545 iiv_algs *a = (iiv_algs *)aa;
547 if (gencomp_checkalgs(&a->ga, asw, e)) return (-1);
549 if ((a->bksz = keysz(asw->hashsz, a->b->keysz)) == 0) {
550 a_format(e, "blkc", "%.*s", strlen(a->b->name) - 4, a->b->name,
551 "no-key-size", "%lu", (unsigned long)asw->hashsz,
555 if (a->b->blksz < a->ga.c->blksz) {
556 a_format(e, "blkc", "%.*s", strlen(a->b->name) - 4, a->b->name,
557 "blksz-insufficient", A_END);
563 static int iiv_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
565 const iiv_algs *a = (const iiv_algs *)aa, *b = (const iiv_algs *)bb;
566 return (gencomp_samealgsp(&a->ga, &b->ga) && a->b == b->b);
569 static void iiv_alginfo(const bulkalgs *aa, admin *adm)
571 const iiv_algs *a = (const iiv_algs *)aa;
572 gencomp_alginfo(&a->ga, adm);
574 "blkc=%.*s", strlen(a->b->name) - 4, a->b->name,
575 "blkc-keysz=%lu", (unsigned long)a->bksz,
576 "blkc-blksz=%lu", (unsigned long)a->b->blksz,
580 static size_t iiv_overhead(const bulkalgs *aa)
581 { const iiv_algs *a = (const iiv_algs *)aa; return (a->ga.tagsz + SEQSZ); }
583 static size_t iiv_expsz(const bulkalgs *aa)
585 const iiv_algs *a = (const iiv_algs *)aa;
586 return (gencomp_expsz(&a->ga));
589 static bulkctx *iiv_genkeys(const bulkalgs *aa, const struct rawkey *rk)
591 const iiv_algs *a = (const iiv_algs *)aa;
592 iiv_ctx *bc = CREATE(iiv_ctx);
596 bc->tagsz = a->ga.tagsz;
597 for (i = 0; i < NDIR; i++) {
598 ks_derivekey(k, a->ga.cksz, rk, i, "encryption");
599 bc->d[i].c = GC_INIT(a->ga.c, k, a->ga.cksz);
600 ks_derivekey(k, a->bksz, rk, i, "blkc");
601 bc->d[i].b = GC_INIT(a->b, k, a->bksz);
602 ks_derivekey(k, a->ga.mksz, rk, i, "integrity");
603 bc->d[i].m = GM_KEY(a->ga.m, k, a->ga.mksz);
608 static bulkchal *iiv_genchal(const bulkalgs *aa)
610 const iiv_algs *a = (const iiv_algs *)aa;
611 return (gencomp_genchal(&a->ga));
613 #define iiv_chaltag gencomp_chaltag
614 #define iiv_chalvrf gencomp_chalvrf
615 #define iiv_freechal gencomp_freechal
617 static void iiv_freealgs(bulkalgs *aa)
618 { iiv_algs *a = (iiv_algs *)aa; DESTROY(a); }
620 static void iiv_freectx(bulkctx *bbc)
622 iiv_ctx *bc = (iiv_ctx *)bbc;
625 for (i = 0; i < NDIR; i++) {
626 GC_DESTROY(bc->d[i].c);
627 GC_DESTROY(bc->d[i].b);
628 GM_DESTROY(bc->d[i].m);
633 #define TRACE_PRESEQ(qseq, ivsz) do { IF_TRACING(T_KEYSET, { \
634 trace_block(T_CRYPTO, "crypto: IV derivation input", (qseq), (ivsz)); \
637 static int iiv_encrypt(bulkctx *bbc, unsigned ty,
638 buf *b, buf *bb, uint32 seq)
640 iiv_ctx *bc = (iiv_ctx *)bbc;
642 gcipher *c = bc->d[DIR_OUT].c, *blkc = bc->d[DIR_OUT].b;
643 const octet *p = BCUR(b);
644 size_t sz = BLEFT(b);
645 octet *qmac, *qseq, *qpk;
646 size_t ivsz = GC_CLASS(c)->blksz, blkcsz = GC_CLASS(blkc)->blksz;
647 size_t tagsz = bc->tagsz;
650 /* --- Determine the ciphertext layout --- */
652 if (buf_ensure(bb, tagsz + SEQSZ + sz)) return (0);
653 qmac = BCUR(bb); qseq = qmac + tagsz; qpk = qseq + SEQSZ;
654 BSTEP(bb, tagsz + SEQSZ + sz);
656 /* --- Store the type --- *
658 * This isn't transmitted, but it's covered by the MAC.
663 /* --- Store the sequence number --- */
667 /* --- Establish an initialization vector if necessary --- */
670 memset(buf_u, 0, blkcsz - SEQSZ);
671 memcpy(buf_u + blkcsz - SEQSZ, qseq, SEQSZ);
672 TRACE_PRESEQ(buf_u, ivsz);
673 GC_ENCRYPT(blkc, buf_u, buf_u, blkcsz);
675 TRACE_IV(buf_u, ivsz);
678 /* --- Encrypt the packet --- */
680 GC_ENCRYPT(c, p, qpk, sz);
683 /* --- Compute a MAC over type, sequence number, and ciphertext --- */
686 h = GM_INIT(bc->d[DIR_OUT].m);
687 GH_HASH(h, t, sizeof(t));
688 GH_HASH(h, qseq, SEQSZ + sz);
689 memcpy(qmac, GH_DONE(h, 0), tagsz);
691 TRACE_MAC(qmac, tagsz);
694 /* --- We're done --- */
699 static int iiv_decrypt(bulkctx *bbc, unsigned ty,
700 buf *b, buf *bb, uint32 *seq)
702 iiv_ctx *bc = (iiv_ctx *)bbc;
703 const octet *pmac, *pseq, *ppk;
704 size_t psz = BLEFT(b);
708 gcipher *c = bc->d[DIR_IN].c, *blkc = bc->d[DIR_IN].b;
709 size_t ivsz = GC_CLASS(c)->blksz, blkcsz = GC_CLASS(blkc)->blksz;
710 size_t tagsz = bc->tagsz;
713 /* --- Break up the packet into its components --- */
715 if (psz < SEQSZ + tagsz) {
716 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
717 return (KSERR_MALFORMED);
719 sz = psz - SEQSZ - tagsz;
720 pmac = BCUR(b); pseq = pmac + tagsz; ppk = pseq + SEQSZ;
723 /* --- Verify the MAC on the packet --- */
726 h = GM_INIT(bc->d[DIR_IN].m);
727 GH_HASH(h, t, sizeof(t));
728 GH_HASH(h, pseq, SEQSZ + sz);
729 CHECK_MAC(h, pmac, tagsz);
732 /* --- Decrypt the packet --- */
735 memset(buf_u, 0, blkcsz - SEQSZ);
736 memcpy(buf_u + blkcsz - SEQSZ, pseq, SEQSZ);
737 TRACE_PRESEQ(buf_u, ivsz);
738 GC_ENCRYPT(blkc, buf_u, buf_u, blkcsz);
740 TRACE_IV(buf_u, ivsz);
742 GC_DECRYPT(c, ppk, q, sz);
744 /* --- Finished --- */
751 /*----- The NaCl box transform --------------------------------------------*
753 * This transform is very similar to the NaCl `crypto_secretbox' transform
754 * described in Bernstein, `Cryptography in NaCl', with the difference that,
755 * rather than using XSalsa20, we use either Salsa20/r or ChaChar, because we
756 * have no need of XSalsa20's extended nonce. The default cipher is Salsa20.
758 * Salsa20 and ChaCha accept a 64-bit nonce. The low 32 bits are the
759 * sequence number, and the high 32 bits are the type, both big-endian.
766 * A stream is generated by concatenating the raw output blocks generated
767 * with this nonce and successive counter values starting from zero. The
768 * first 32 bytes of the stream are used as a key for Poly1305: the first 16
769 * bytes are the universal hash key r, and the second 16 bytes are the mask
772 * +------+------+ +------...------+
773 * | r | s | | keystream |
774 * +------+------+ +------...------+
777 * The remainder of the stream is XORed with the incoming plaintext to form a
778 * ciphertext with the same length. The ciphertext (only) is then tagged
779 * using Poly1305. The tag, sequence number, and ciphertext are concatenated
780 * in this order, and transmitted.
783 * +---...---+------+------...------+
784 * | tag | seq | ciphertext |
785 * +---...---+------+------...------+
788 * Note that there is no need to authenticate the type separately, since it
789 * was used to select the cipher nonce, and hence the Poly1305 key. The
790 * Poly1305 tag length is fixed.
793 typedef struct naclbox_algs {
795 const gccipher *c; size_t cksz;
798 typedef struct naclbox_ctx {
800 struct { gcipher *c; } d[NDIR];
804 static bulkalgs *naclbox_getalgs(const algswitch *asw, dstr *e,
805 key_file *kf, key *k)
807 naclbox_algs *a = CREATE(naclbox_algs);
812 /* --- Collect the selected cipher and check that it's supported --- */
814 p = key_getattr(kf, k, "cipher");
815 if (!p || strcmp(p, "salsa20") == 0) a->c = &salsa20;
816 else if (strcmp(p, "salsa20/12") == 0) a->c = &salsa2012;
817 else if (strcmp(p, "salsa20/8") == 0) a->c = &salsa208;
818 else if (strcmp(p, "chacha20") == 0) a->c = &chacha20;
819 else if (strcmp(p, "chacha12") == 0) a->c = &chacha12;
820 else if (strcmp(p, "chacha8") == 0) a->c = &chacha8;
822 a_format(e, "unknown-cipher", "%s", p, A_END);
826 /* --- Collect the selected MAC, and check the tag length --- */
828 p = key_getattr(kf, k, "mac");
831 else if (strncmp(p, "poly1305", 8) != 0 || (p[8] && p[8] != '/')) {
832 a_format(e, "unknown-mac", "%s", p, A_END);
834 } else if (p[8] == '/') {
835 n = strtoul(p + 9, &qq, 0);
837 a_format(e, "bad-tag-length-string", "%s", p + 9, A_END);
841 a_format(e, "bad-tag-length", "%lu", n, A_END);
853 static void naclbox_tracealgs(const bulkalgs *aa)
855 const naclbox_algs *a = (const naclbox_algs *)aa;
857 trace(T_CRYPTO, "crypto: cipher = %s", a->c->name);
858 trace(T_CRYPTO, "crypto: mac = poly1305/128");
862 static int naclbox_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
864 naclbox_algs *a = (naclbox_algs *)aa;
866 if ((a->cksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
867 a_format(e, "cipher", "%s", a->c->name,
868 "no-key-size", "%lu", (unsigned long)asw->hashsz,
875 static int naclbox_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
877 const naclbox_algs *a = (const naclbox_algs *)aa,
878 *b = (const naclbox_algs *)bb;
879 return (a->c == b->c);
882 static void naclbox_alginfo(const bulkalgs *aa, admin *adm)
884 const naclbox_algs *a = (const naclbox_algs *)aa;
885 a_info(adm, "cipher=%s", a->c->name, "cipher-keysz=32", A_END);
886 a_info(adm, "mac=poly1305", "mac-tagsz=16", A_END);
889 static size_t naclbox_overhead(const bulkalgs *aa)
890 { return (POLY1305_TAGSZ + SEQSZ); }
892 static size_t naclbox_expsz(const bulkalgs *aa)
893 { return (MEG(2048)); }
895 static bulkctx *naclbox_genkeys(const bulkalgs *aa, const struct rawkey *rk)
897 const naclbox_algs *a = (const naclbox_algs *)aa;
898 naclbox_ctx *bc = CREATE(naclbox_ctx);
902 for (i = 0; i < NDIR; i++) {
903 ks_derivekey(k, a->cksz, rk, i, "encryption");
904 bc->d[i].c = GC_INIT(a->c, k, a->cksz);
909 typedef struct naclbox_chal {
914 static bulkchal *naclbox_genchal(const bulkalgs *aa)
916 const naclbox_algs *a = (const naclbox_algs *)aa;
917 naclbox_chal *c = CREATE(naclbox_chal);
918 rand_get(RAND_GLOBAL, buf_t, a->cksz);
919 c->c = GC_INIT(a->c, buf_t, a->cksz);
921 trace(T_CHAL, "chal: generated new challenge key");
922 trace_block(T_CRYPTO, "chal: new key", buf_t, a->cksz);
928 static int naclbox_chaltag(bulkchal *bc, const void *m, size_t msz, void *t)
930 naclbox_chal *c = (naclbox_chal *)bc;
931 octet b0[SALSA20_NONCESZ];
932 assert(msz <= sizeof(b0));
933 memcpy(b0, m, msz); memset(b0 + msz, 0, sizeof(b0) - msz);
935 GC_ENCRYPT(c->c, 0, t, c->_b.tagsz);
939 static int naclbox_chalvrf(bulkchal *bc, const void *m, size_t msz,
942 naclbox_chal *c = (naclbox_chal *)bc;
943 octet b0[SALSA20_NONCESZ], b1[16];
944 assert(msz <= sizeof(b0)); assert(c->_b.tagsz <= sizeof(b1));
945 memcpy(b0, m, msz); memset(b0 + msz, 0, sizeof(b0) - msz);
947 GC_ENCRYPT(c->c, 0, b1, c->_b.tagsz);
948 return (ct_memeq(t, b1, c->_b.tagsz) ? 0 : -1);
951 static void naclbox_freechal(bulkchal *bc)
952 { naclbox_chal *c = (naclbox_chal *)bc; GC_DESTROY(c->c); DESTROY(c); }
954 static void naclbox_freealgs(bulkalgs *aa)
955 { naclbox_algs *a = (naclbox_algs *)aa; DESTROY(a); }
957 static void naclbox_freectx(bulkctx *bbc)
959 naclbox_ctx *bc = (naclbox_ctx *)bbc;
962 for (i = 0; i < NDIR; i++) GC_DESTROY(bc->d[i].c);
966 static int naclbox_encrypt(bulkctx *bbc, unsigned ty,
967 buf *b, buf *bb, uint32 seq)
969 naclbox_ctx *bc = (naclbox_ctx *)bbc;
970 gcipher *c = bc->d[DIR_OUT].c;
973 const octet *p = BCUR(b);
974 size_t sz = BLEFT(b);
975 octet *qmac, *qseq, *qpk;
977 /* --- Determine the ciphertext layout --- */
979 if (buf_ensure(bb, POLY1305_TAGSZ + SEQSZ + sz)) return (0);
980 qmac = BCUR(bb); qseq = qmac + POLY1305_TAGSZ; qpk = qseq + SEQSZ;
981 BSTEP(bb, POLY1305_TAGSZ + SEQSZ + sz);
983 /* --- Construct and set the nonce --- */
986 memcpy(buf_u, qseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
988 TRACE_IV(buf_u, SALSA20_NONCESZ);
990 /* --- Determine the MAC key --- */
992 GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
993 poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
994 poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
996 /* --- Encrypt the message --- */
998 GC_ENCRYPT(c, p, qpk, sz);
1001 /* --- Compute the MAC --- */
1003 poly1305_hash(&poly, qpk, sz);
1004 poly1305_done(&poly, qmac);
1005 TRACE_MAC(qmac, POLY1305_TAGSZ);
1007 /* --- We're done --- */
1012 static int naclbox_decrypt(bulkctx *bbc, unsigned ty,
1013 buf *b, buf *bb, uint32 *seq)
1015 naclbox_ctx *bc = (naclbox_ctx *)bbc;
1016 gcipher *c = bc->d[DIR_IN].c;
1019 const octet *pmac, *pseq, *ppk;
1020 size_t psz = BLEFT(b);
1022 octet *q = BCUR(bb);
1024 /* --- Break up the packet into its components --- */
1026 if (psz < SEQSZ + POLY1305_TAGSZ) {
1027 T( trace(T_KEYSET, "keyset: block too small for keyset"); )
1028 return (KSERR_MALFORMED);
1030 sz = psz - SEQSZ - POLY1305_TAGSZ;
1031 pmac = BCUR(b); pseq = pmac + POLY1305_TAGSZ; ppk = pseq + SEQSZ;
1033 /* --- Construct and set the nonce --- */
1035 memcpy(buf_u, pseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
1037 TRACE_IV(buf_u, SALSA20_NONCESZ);
1039 /* --- Determine the MAC key --- */
1041 GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
1042 poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
1043 poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
1045 /* --- Verify the MAC on the packet --- */
1047 poly1305_hash(&poly, ppk, sz);
1048 poly1305_done(&poly, buf_u);
1049 if (!ct_memeq(buf_u, pmac, POLY1305_TAGSZ)) {
1050 TRACE_MACERR(pmac, POLY1305_TAGSZ);
1051 return (KSERR_DECRYPT);
1054 /* --- Decrypt the packet --- */
1056 GC_DECRYPT(c, ppk, q, sz);
1058 /* --- Finished --- */
1060 *seq = LOAD32(pseq);
1065 /*----- Bulk crypto transform table ---------------------------------------*/
1067 const bulkops bulktab[] = {
1071 #define BULK(name, pre) \
1072 { name, pre##_getalgs, T( pre##_tracealgs COMMA ) \
1073 pre##_checkalgs, pre##_samealgsp, \
1074 pre##_alginfo, pre##_overhead, pre##_expsz, \
1075 pre##_genkeys, pre##_genchal, pre##_freealgs, \
1076 pre##_encrypt, pre##_decrypt, pre##_freectx, \
1077 pre##_chaltag, pre##_chalvrf, pre##_freechal }
1081 BULK("naclbox", naclbox),
1087 /*----- That's all, folks -------------------------------------------------*/