3 * AUTHOR: Rudolf Polzer - divVerent@xonotic.org
5 * Copyright (c) 2010, Rudolf Polzer
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the copyright holder nor the names of contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 #include "d0_blind_id.h"
40 #include "d0_bignum.h"
43 // old "positive" protocol, uses one extra mod_inv in verify stages
44 // #define D0_BLIND_ID_POSITIVE_PROTOCOL
47 #define SHA_DIGESTSIZE 32
48 const unsigned char *sha(unsigned char *h, const unsigned char *in, size_t len)
50 d0_blind_id_util_sha256((char *) h, (const char *) in, len);
54 // for zero knowledge, we need multiple instances of schnorr ID scheme... should normally be sequential
55 // parallel schnorr ID is not provably zero knowledge :(
56 // (evil verifier can know all questions in advance, so sequential is disadvantage for him)
57 // we'll just live with a 1:1048576 chance of cheating, and support reauthenticating
59 #define SCHNORR_BITS 20
60 // probability of cheat: 2^(-bits+1)
62 #define SCHNORR_HASHSIZE SHA_DIGESTSIZE
63 // cannot be >= SHA_DIGESTSIZE
64 // *8 must be >= SCHNORR_BITS
65 // no need to save bits here
67 #define MSGSIZE 640 // ought to be enough for anyone
71 // signing (Xonotic pub and priv key)
72 d0_bignum_t *rsa_n, *rsa_e, *rsa_d;
74 // public data (Schnorr ID)
75 d0_bignum_t *schnorr_G;
77 // private data (player ID private key)
78 d0_bignum_t *schnorr_s;
80 // public data (player ID public key, this is what the server gets to know)
81 d0_bignum_t *schnorr_g_to_s;
82 d0_bignum_t *schnorr_H_g_to_s_signature; // 0 when signature is invalid
83 // as hash function H, we get the SHA1 and reinterpret as bignum - yes, it always is < 160 bits
86 d0_bignum_t *rsa_blind_signature_camouflage; // random number blind signature
88 d0_bignum_t *r; // random number for schnorr ID
89 d0_bignum_t *t; // for DH key exchange
90 d0_bignum_t *g_to_t; // for DH key exchange
91 d0_bignum_t *other_g_to_t; // for DH key exchange
92 d0_bignum_t *challenge; // challenge
94 char msghash[SCHNORR_HASHSIZE]; // init hash
95 char msg[MSGSIZE]; // message
96 size_t msglen; // message length
101 #define CHECK(x) do { if(!(x)) { fprintf(stderr, "CHECK FAILED (%s:%d): %s\n", __FILE__, __LINE__, #x); goto fail; } } while(0)
102 #define CHECK_ASSIGN(var, value) do { d0_bignum_t *val; val = value; if(!val) { fprintf(stderr, "CHECK FAILED (%s:%d): %s\n", __FILE__, __LINE__, #value); goto fail; } var = val; } while(0)
104 #define CHECK(x) do { if(!(x)) goto fail; } while(0)
105 #define CHECK_ASSIGN(var, value) do { d0_bignum_t *val; val = value; if(!val) goto fail; var = val; } while(0)
108 #define USING(x) if(!(ctx->x)) return 0
112 static d0_bignum_t *zero, *one, *four;
114 static d0_bignum_t *temp0, *temp1, *temp2, *temp3, *temp4;
115 static void *tempmutex = NULL; // hold this mutex when using temp0 to temp4
116 #define USINGTEMPS() int locked = 0
117 #define LOCKTEMPS() do { if(!locked) d0_lockmutex(tempmutex); locked = 1; } while(0)
118 #define UNLOCKTEMPS() do { if(locked) d0_unlockmutex(tempmutex); locked = 0; } while(0);
120 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_INITIALIZE(void)
124 tempmutex = d0_createmutex();
126 CHECK(d0_bignum_INITIALIZE());
127 CHECK_ASSIGN(zero, d0_bignum_int(zero, 0));
128 CHECK_ASSIGN(one, d0_bignum_int(one, 1));
129 CHECK_ASSIGN(four, d0_bignum_int(four, 4));
130 CHECK_ASSIGN(temp0, d0_bignum_int(temp0, 0));
131 CHECK_ASSIGN(temp1, d0_bignum_int(temp1, 0));
132 CHECK_ASSIGN(temp2, d0_bignum_int(temp2, 0));
133 CHECK_ASSIGN(temp3, d0_bignum_int(temp3, 0));
134 CHECK_ASSIGN(temp4, d0_bignum_int(temp4, 0));
142 void d0_blind_id_SHUTDOWN(void)
146 d0_bignum_free(zero);
148 d0_bignum_free(four);
149 d0_bignum_free(temp0);
150 d0_bignum_free(temp1);
151 d0_bignum_free(temp2);
152 d0_bignum_free(temp3);
153 d0_bignum_free(temp4);
154 d0_bignum_SHUTDOWN();
156 d0_destroymutex(tempmutex);
161 static d0_bignum_t *d0_dl_get_order(d0_bignum_t *o, const d0_bignum_t *G)
163 CHECK_ASSIGN(o, d0_bignum_sub(o, G, one));
164 CHECK(d0_bignum_shl(o, o, -1)); // order o = (G-1)/2
170 d0_bignum_t *d0_dl_get_from_order(d0_bignum_t *G, const d0_bignum_t *o)
172 CHECK_ASSIGN(G, d0_bignum_shl(G, o, 1));
173 CHECK(d0_bignum_add(G, G, one));
179 // temps must NOT be locked when calling this
180 static D0_BOOL d0_dl_generate_key(size_t size, d0_bignum_t *G)
182 USINGTEMPS(); // using: temp0
188 CHECK(d0_bignum_rand_bit_exact(temp0, size-1));
189 if(d0_bignum_isprime(temp0, 0) == 0)
191 CHECK(d0_dl_get_from_order(G, temp0));
192 if(d0_bignum_isprime(G, 10) == 0)
194 if(d0_bignum_isprime(temp0, 10) == 0) // finish the previous test
205 // temps must NOT be locked when calling this
206 static D0_BOOL d0_rsa_generate_key(size_t size, d0_blind_id_t *ctx)
208 USINGTEMPS(); // uses temp1 to temp4
211 int pb = (size + 1)/2;
218 // we use ctx->rsa_d for the first result so that we can unlock temps later
222 CHECK(d0_bignum_rand_bit_exact(ctx->rsa_d, pb));
223 if(d0_bignum_isprime(ctx->rsa_d, 10) == 0)
228 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one));
229 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
230 if(!d0_bignum_cmp(temp4, one))
242 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
243 if(!d0_bignum_cmp(temp1, ctx->rsa_d))
251 if(d0_bignum_isprime(temp1, 10) == 0)
256 CHECK(d0_bignum_sub(temp3, temp1, one));
257 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
258 if(!d0_bignum_cmp(temp4, one))
260 // we do NOT unlock, as we still need temp1 and temp3
269 // ctx->rsa_n = ctx->rsa_d*temp1
270 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
272 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
273 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
274 CHECK(d0_bignum_mul(temp0, temp2, temp3));
275 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
283 // temps must NOT be locked when calling this
284 static D0_BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass)
286 USINGTEMPS(); // uses temp1 to temp4
289 int pb = (size + 1)/2;
296 // we use ctx->rsa_d for the first result so that we can unlock temps later
300 CHECK(d0_bignum_rand_bit_exact(ctx->rsa_d, pb));
301 if(d0_bignum_isprime(ctx->rsa_d, 10) == 0)
306 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one));
307 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
308 if(!d0_bignum_cmp(temp4, one))
320 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
321 if(!d0_bignum_cmp(temp1, ctx->rsa_d))
330 // n = ctx->rsa_d*temp1
331 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
332 if(reject(ctx, pass))
338 if(d0_bignum_isprime(temp1, 10) == 0)
343 CHECK(d0_bignum_sub(temp3, temp1, one));
344 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
345 if(!d0_bignum_cmp(temp4, one))
347 // we do NOT unlock, as we still need temp3
356 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
357 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
358 CHECK(d0_bignum_mul(ctx->rsa_d, temp2, temp3));
359 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
367 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_destructive(unsigned char *convbuf, size_t sz, unsigned char *outbuf, size_t outbuflen)
373 while(n > SHA_DIGESTSIZE)
375 memcpy(outbuf, sha(shabuf, convbuf, sz), SHA_DIGESTSIZE);
376 outbuf += SHA_DIGESTSIZE;
378 for(i = 0; i < sz; ++i)
380 break; // stop until no carry
382 memcpy(outbuf, sha(shabuf, convbuf, sz), n);
386 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_bignum(const d0_bignum_t *in, unsigned char *outbuf, size_t outbuflen)
388 unsigned char convbuf[1024];
391 CHECK(d0_bignum_export_unsigned(in, convbuf, sizeof(convbuf)) >= 0);
392 sz = (d0_bignum_size(in) + 7) / 8;
393 CHECK(d0_longhash_destructive(convbuf, sz, outbuf, outbuflen));
400 void d0_blind_id_clear(d0_blind_id_t *ctx)
402 if(ctx->rsa_n) d0_bignum_free(ctx->rsa_n);
403 if(ctx->rsa_e) d0_bignum_free(ctx->rsa_e);
404 if(ctx->rsa_d) d0_bignum_free(ctx->rsa_d);
405 if(ctx->schnorr_G) d0_bignum_free(ctx->schnorr_G);
406 if(ctx->schnorr_s) d0_bignum_free(ctx->schnorr_s);
407 if(ctx->schnorr_g_to_s) d0_bignum_free(ctx->schnorr_g_to_s);
408 if(ctx->schnorr_H_g_to_s_signature) d0_bignum_free(ctx->schnorr_H_g_to_s_signature);
409 if(ctx->rsa_blind_signature_camouflage) d0_bignum_free(ctx->rsa_blind_signature_camouflage);
410 if(ctx->r) d0_bignum_free(ctx->r);
411 if(ctx->challenge) d0_bignum_free(ctx->challenge);
412 if(ctx->t) d0_bignum_free(ctx->t);
413 if(ctx->g_to_t) d0_bignum_free(ctx->g_to_t);
414 if(ctx->other_g_to_t) d0_bignum_free(ctx->other_g_to_t);
415 memset(ctx, 0, sizeof(*ctx));
418 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
420 d0_blind_id_clear(ctx);
421 if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n));
422 if(src->rsa_e) CHECK_ASSIGN(ctx->rsa_e, d0_bignum_mov(NULL, src->rsa_e));
423 if(src->rsa_d) CHECK_ASSIGN(ctx->rsa_d, d0_bignum_mov(NULL, src->rsa_d));
424 if(src->schnorr_G) CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_mov(NULL, src->schnorr_G));
425 if(src->schnorr_s) CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_mov(NULL, src->schnorr_s));
426 if(src->schnorr_g_to_s) CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mov(NULL, src->schnorr_g_to_s));
427 if(src->schnorr_H_g_to_s_signature) CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_mov(NULL, src->schnorr_H_g_to_s_signature));
428 if(src->rsa_blind_signature_camouflage) CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_mov(NULL, src->rsa_blind_signature_camouflage));
429 if(src->r) CHECK_ASSIGN(ctx->r, d0_bignum_mov(NULL, src->r));
430 if(src->challenge) CHECK_ASSIGN(ctx->challenge, d0_bignum_mov(NULL, src->challenge));
431 if(src->t) CHECK_ASSIGN(ctx->t, d0_bignum_mov(NULL, src->t));
432 if(src->g_to_t) CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mov(NULL, src->g_to_t));
433 if(src->other_g_to_t) CHECK_ASSIGN(ctx->other_g_to_t, d0_bignum_mov(NULL, src->other_g_to_t));
434 memcpy(ctx->msg, src->msg, sizeof(ctx->msg));
435 ctx->msglen = src->msglen;
436 memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash));
439 d0_blind_id_clear(ctx);
443 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key_fastreject(d0_blind_id_t *ctx, int k, d0_fastreject_function reject, void *pass)
445 REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
447 CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
448 CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
449 CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
451 CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
453 CHECK(d0_rsa_generate_key(k+1, ctx)); // must fit G for sure
459 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
461 return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL);
464 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
466 d0_iobuf_t *in = NULL;
468 REPLACING(rsa_n); REPLACING(rsa_e); REPLACING(rsa_d);
470 in = d0_iobuf_open_read(inbuf, inbuflen);
472 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
473 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
474 CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, ctx->rsa_d));
475 return d0_iobuf_close(in, NULL);
478 d0_iobuf_close(in, NULL);
482 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
484 d0_iobuf_t *in = NULL;
486 REPLACING(rsa_n); REPLACING(rsa_e);
488 in = d0_iobuf_open_read(inbuf, inbuflen);
489 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
490 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
491 return d0_iobuf_close(in, NULL);
494 d0_iobuf_close(in, NULL);
498 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
500 d0_iobuf_t *out = NULL;
502 USING(rsa_n); USING(rsa_e); USING(rsa_d);
504 out = d0_iobuf_open_write(outbuf, *outbuflen);
505 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
506 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
507 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_d));
508 return d0_iobuf_close(out, outbuflen);
511 d0_iobuf_close(out, outbuflen);
515 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
517 d0_iobuf_t *out = NULL;
519 USING(rsa_n); USING(rsa_e);
521 out = d0_iobuf_open_write(outbuf, *outbuflen);
522 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
523 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
524 return d0_iobuf_close(out, outbuflen);
527 if(!d0_iobuf_close(out, outbuflen))
532 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
534 d0_iobuf_t *out = NULL;
535 unsigned char convbuf[2048];
536 d0_iobuf_t *conv = NULL;
540 USING(rsa_n); USING(rsa_e);
542 out = d0_iobuf_open_write(outbuf, *outbuflen);
543 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
545 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
546 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
547 CHECK(d0_iobuf_close(conv, &sz));
550 n = (*outbuflen / 4) * 3;
551 if(n > SHA_DIGESTSIZE)
553 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
554 CHECK(d0_iobuf_conv_base64_out(out));
556 return d0_iobuf_close(out, outbuflen);
560 d0_iobuf_close(conv, &sz);
561 d0_iobuf_close(out, outbuflen);
565 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx)
568 REPLACING(schnorr_G);
570 CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_zero(ctx->schnorr_G));
571 CHECK(d0_dl_generate_key(d0_bignum_size(ctx->rsa_n)-1, ctx->schnorr_G));
577 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
579 d0_iobuf_t *in = NULL;
581 REPLACING(schnorr_G);
583 in = d0_iobuf_open_read(inbuf, inbuflen);
584 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
585 return d0_iobuf_close(in, NULL);
588 d0_iobuf_close(in, NULL);
592 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
594 d0_iobuf_t *out = NULL;
598 out = d0_iobuf_open_write(outbuf, *outbuflen);
599 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
600 return d0_iobuf_close(out, outbuflen);
603 d0_iobuf_close(out, outbuflen);
607 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx)
609 USINGTEMPS(); // temps: temp0 = order
611 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s);
614 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
615 CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_rand_range(ctx->schnorr_s, zero, temp0));
616 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mod_pow(ctx->schnorr_g_to_s, four, ctx->schnorr_s, ctx->schnorr_G));
617 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
626 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
628 d0_iobuf_t *out = NULL;
629 unsigned char hashbuf[2048];
632 USINGTEMPS(); // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge
633 USING(rsa_n); USING(rsa_e); USING(schnorr_g_to_s);
634 REPLACING(rsa_blind_signature_camouflage);
636 out = d0_iobuf_open_write(outbuf, *outbuflen);
638 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_rand_bit_atmost(ctx->rsa_blind_signature_camouflage, d0_bignum_size(ctx->rsa_n)));
639 CHECK(d0_bignum_mod_pow(temp0, ctx->rsa_blind_signature_camouflage, ctx->rsa_e, ctx->rsa_n));
641 // we will actually sign HA(4^s) to prevent a malleability attack!
643 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
644 if(sz > sizeof(hashbuf))
645 sz = sizeof(hashbuf);
646 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
647 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
650 CHECK(d0_bignum_mod_mul(temp1, temp2, temp0, ctx->rsa_n));
651 CHECK(d0_iobuf_write_bignum(out, temp1));
653 return d0_iobuf_close(out, outbuflen);
657 d0_iobuf_close(out, outbuflen);
661 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_answer_private_id_request(const d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen)
663 d0_iobuf_t *in = NULL;
664 d0_iobuf_t *out = NULL;
666 USINGTEMPS(); // temps: temp0 input, temp1 temp0^d
667 USING(rsa_d); USING(rsa_n);
669 in = d0_iobuf_open_read(inbuf, inbuflen);
670 out = d0_iobuf_open_write(outbuf, *outbuflen);
673 CHECK(d0_iobuf_read_bignum(in, temp0));
674 CHECK(d0_bignum_mod_pow(temp1, temp0, ctx->rsa_d, ctx->rsa_n));
675 CHECK(d0_iobuf_write_bignum(out, temp1));
678 d0_iobuf_close(in, NULL);
679 return d0_iobuf_close(out, outbuflen);
683 d0_iobuf_close(in, NULL);
684 d0_iobuf_close(out, outbuflen);
688 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
690 d0_iobuf_t *in = NULL;
692 USINGTEMPS(); // temps: temp0 input, temp1 rsa_blind_signature_camouflage^-1
693 USING(rsa_blind_signature_camouflage); USING(rsa_n);
694 REPLACING(schnorr_H_g_to_s_signature);
696 in = d0_iobuf_open_read(inbuf, inbuflen);
700 CHECK(d0_iobuf_read_bignum(in, temp0));
701 CHECK(d0_bignum_mod_inv(temp1, ctx->rsa_blind_signature_camouflage, ctx->rsa_n));
702 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_mod_mul(ctx->schnorr_H_g_to_s_signature, temp0, temp1, ctx->rsa_n));
705 return d0_iobuf_close(in, NULL);
709 d0_iobuf_close(in, NULL);
713 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_request_camouflage(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
715 d0_iobuf_t *in = NULL;
717 REPLACING(rsa_blind_signature_camouflage);
719 in = d0_iobuf_open_read(inbuf, inbuflen);
721 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_iobuf_read_bignum(in, ctx->rsa_blind_signature_camouflage));
723 return d0_iobuf_close(in, NULL);
726 d0_iobuf_close(in, NULL);
730 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_request_camouflage(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
732 d0_iobuf_t *out = NULL;
734 USING(rsa_blind_signature_camouflage);
736 out = d0_iobuf_open_write(outbuf, *outbuflen);
738 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_blind_signature_camouflage));
740 return d0_iobuf_close(out, outbuflen);
743 d0_iobuf_close(out, outbuflen);
747 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
749 d0_iobuf_t *in = NULL;
751 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
753 in = d0_iobuf_open_read(inbuf, inbuflen);
755 CHECK_ASSIGN(ctx->schnorr_s, d0_iobuf_read_bignum(in, ctx->schnorr_s));
756 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
757 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
759 return d0_iobuf_close(in, NULL);
762 d0_iobuf_close(in, NULL);
766 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
768 d0_iobuf_t *in = NULL;
770 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
772 in = d0_iobuf_open_read(inbuf, inbuflen);
774 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
775 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
777 return d0_iobuf_close(in, NULL);
780 d0_iobuf_close(in, NULL);
784 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
786 d0_iobuf_t *out = NULL;
788 USING(schnorr_s); USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
790 out = d0_iobuf_open_write(outbuf, *outbuflen);
792 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_s));
793 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
794 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
796 return d0_iobuf_close(out, outbuflen);
799 d0_iobuf_close(out, outbuflen);
803 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
805 d0_iobuf_t *out = NULL;
807 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
809 out = d0_iobuf_open_write(outbuf, *outbuflen);
811 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
812 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
814 return d0_iobuf_close(out, outbuflen);
817 d0_iobuf_close(out, outbuflen);
821 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, const char *msg, size_t msglen, char *outbuf, size_t *outbuflen)
823 // first run: send 4^s, 4^s signature
824 // 1. get random r, send HASH(4^r)
826 d0_iobuf_t *out = NULL;
827 unsigned char convbuf[1024];
828 d0_iobuf_t *conv = NULL;
833 USINGTEMPS(); // temps: temp0 order, temp0 4^r
836 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
839 REPLACING(r); REPLACING(t); REPLACING(g_to_t);
841 out = d0_iobuf_open_write(outbuf, *outbuflen);
847 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
848 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
849 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
852 // start schnorr ID scheme
853 // generate random number r; x = g^r; send hash of x, remember r, forget x
855 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
857 CHECK_ASSIGN(ctx->r, d0_bignum_int(ctx->r, 4)); // decided by fair dice roll
859 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
862 // initialize Signed Diffie Hellmann
863 // we already have the group order in temp1
865 CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll
867 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
869 // can we SOMEHOW do this with just one mod_pow?
871 CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G));
872 CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G));
875 // hash it, hash it, everybody hash it
876 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
877 CHECK(d0_iobuf_write_bignum(conv, temp0));
878 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
879 CHECK(d0_iobuf_write_packet(conv, msg, msglen));
880 CHECK(d0_iobuf_write_bignum(conv, temp0));
882 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
883 d0_iobuf_close(conv, &sz);
885 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), SCHNORR_HASHSIZE) == SCHNORR_HASHSIZE);
886 CHECK(d0_iobuf_write_packet(out, msg, msglen));
888 return d0_iobuf_close(out, outbuflen);
892 d0_iobuf_close(out, outbuflen);
896 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen, D0_BOOL *status)
897 // first run: get 4^s, 4^s signature
900 // 3. send challenge challenge of SCHNORR_BITS
902 d0_iobuf_t *in = NULL;
903 d0_iobuf_t *out = NULL;
904 unsigned char hashbuf[2048];
907 USINGTEMPS(); // temps: temp0 order, temp0 signature check
910 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
912 REPLACING(schnorr_G);
918 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
921 USING(rsa_e); USING(rsa_n);
922 REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); REPLACING(t);
924 in = d0_iobuf_open_read(inbuf, inbuflen);
925 out = d0_iobuf_open_write(outbuf, *outbuflen);
931 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
932 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
933 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
935 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
936 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
937 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
938 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
939 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
940 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
942 if(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero))
944 // check signature of key (t = k^d, so, t^challenge = k)
946 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
948 // we will actually sign SHA(4^s) to prevent a malleability attack!
949 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
950 if(sz > sizeof(hashbuf))
951 sz = sizeof(hashbuf);
952 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
953 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
955 // + 7 / 8 is too large, so let's mod it
956 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
959 CHECK(d0_bignum_cmp(temp0, temp1) == 0);
963 CHECK(d0_iobuf_read_raw(in, ctx->msghash, SCHNORR_HASHSIZE));
964 ctx->msglen = MSGSIZE;
965 CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen));
969 CHECK_ASSIGN(ctx->challenge, d0_bignum_int(ctx->challenge, 4)); // decided by fair dice roll
971 CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS));
973 CHECK(d0_iobuf_write_bignum(out, ctx->challenge));
975 // Diffie Hellmann send
977 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
979 CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll
981 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
983 CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G));
984 CHECK(d0_iobuf_write_bignum(out, temp0));
988 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
990 d0_iobuf_close(in, NULL);
991 return d0_iobuf_close(out, outbuflen);
995 d0_iobuf_close(in, NULL);
996 d0_iobuf_close(out, outbuflen);
1000 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_response(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen)
1001 // 1. read challenge challenge of SCHNORR_BITS
1002 // 2. reply with r + s * challenge mod order
1004 d0_iobuf_t *in = NULL;
1005 d0_iobuf_t *out = NULL;
1007 USINGTEMPS(); // temps: 0 order, 1 prod, 2 y, 3 challenge
1008 REPLACING(other_g_to_t); REPLACING(t);
1009 USING(schnorr_G); USING(schnorr_s); USING(r); USING(g_to_t);
1011 in = d0_iobuf_open_read(inbuf, inbuflen);
1012 out = d0_iobuf_open_write(outbuf, *outbuflen);
1015 CHECK(d0_iobuf_read_bignum(in, temp3));
1016 CHECK(d0_bignum_cmp(temp3, zero) >= 0);
1017 CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS);
1019 // send response for schnorr ID scheme
1020 // i.challenge. r + ctx->schnorr_s * temp3
1021 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1022 CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_s, temp3, temp0));
1023 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1024 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1026 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1028 CHECK(d0_iobuf_write_bignum(out, temp2));
1031 // Diffie Hellmann recv
1032 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1033 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1034 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1035 // Diffie Hellmann send
1036 CHECK(d0_iobuf_write_bignum(out, ctx->g_to_t));
1038 d0_iobuf_close(in, NULL);
1039 return d0_iobuf_close(out, outbuflen);
1043 d0_iobuf_close(in, NULL);
1044 d0_iobuf_close(out, outbuflen);
1048 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_verify(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen, char *msg, size_t *msglen, D0_BOOL *status)
1049 // 1. read y = r + s * challenge mod order
1050 // 2. verify: g^y (g^s)^-challenge = g^(r+s*challenge-s*challenge) = g^r
1051 // (check using H(g^r) which we know)
1053 d0_iobuf_t *in = NULL;
1054 unsigned char convbuf[1024];
1055 d0_iobuf_t *conv = NULL;
1059 USINGTEMPS(); // temps: 0 y 1 order
1060 USING(challenge); USING(schnorr_G);
1061 REPLACING(other_g_to_t);
1063 in = d0_iobuf_open_read(inbuf, inbuflen);
1067 CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
1068 CHECK(d0_iobuf_read_bignum(in, temp0));
1069 CHECK(d0_bignum_cmp(temp0, zero) >= 0);
1070 CHECK(d0_bignum_cmp(temp0, temp1) < 0);
1072 // verify schnorr ID scheme
1073 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1074 // we need 4^r = 4^temp0 (g^s)^-challenge
1075 CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G));
1076 CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G));
1078 // we need 4^r = 4^temp0 (g^s)^challenge
1079 CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_g_to_s, ctx->challenge, ctx->schnorr_G));
1081 CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G));
1082 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));
1084 // Diffie Hellmann recv
1085 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1086 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1087 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1089 // hash it, hash it, everybody hash it
1090 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1091 CHECK(d0_iobuf_write_bignum(conv, temp3));
1092 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1093 CHECK(d0_iobuf_write_packet(conv, ctx->msg, ctx->msglen));
1094 CHECK(d0_iobuf_write_bignum(conv, temp3));
1096 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1097 d0_iobuf_close(conv, &sz);
1099 if(memcmp(sha(shabuf, convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE))
1101 // FAIL (not owned by player)
1106 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1108 if(ctx->msglen <= *msglen)
1109 memcpy(msg, ctx->msg, ctx->msglen);
1111 memcpy(msg, ctx->msg, *msglen);
1112 *msglen = ctx->msglen;
1114 d0_iobuf_close(in, NULL);
1119 d0_iobuf_close(in, NULL);
1123 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx)
1126 unsigned char hashbuf[2048];
1128 USINGTEMPS(); // temps: 2 hash
1129 REPLACING(schnorr_H_g_to_s_signature);
1130 USING(schnorr_g_to_s); USING(rsa_d); USING(rsa_n);
1134 // we will actually sign SHA(4^s) to prevent a malleability attack!
1135 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1136 if(sz > sizeof(hashbuf))
1137 sz = sizeof(hashbuf);
1138 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1140 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1142 // + 7 / 8 is too large, so let's mod it
1143 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1144 CHECK(d0_bignum_mod_pow(ctx->schnorr_H_g_to_s_signature, temp1, ctx->rsa_d, ctx->rsa_n));
1154 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_sign_internal(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, D0_BOOL with_msg, const char *message, size_t msglen, char *outbuf, size_t *outbuflen)
1156 d0_iobuf_t *out = NULL;
1157 unsigned char *convbuf = NULL;
1158 unsigned char hashbuf[2048];
1159 d0_iobuf_t *conv = NULL;
1162 USINGTEMPS(); // temps: 0 order 1 4^r 2 hash
1165 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1171 out = d0_iobuf_open_write(outbuf, *outbuflen);
1177 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
1178 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
1179 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
1182 // start schnorr SIGNATURE scheme
1183 // generate random number r; x = g^r; send hash of H(m||r), remember r, forget x
1185 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1186 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
1187 CHECK(d0_bignum_mod_pow(temp1, four, ctx->r, ctx->schnorr_G));
1189 // hash it, hash it, everybody hash it
1190 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1191 CHECK(d0_iobuf_write_packet(conv, message, msglen));
1192 CHECK(d0_iobuf_write_bignum(conv, temp1));
1193 d0_iobuf_close(conv, &sz);
1195 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1198 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1199 CHECK(d0_iobuf_write_bignum(out, temp2));
1201 // multiply with secret, sub k, modulo order
1202 CHECK(d0_bignum_mod_mul(temp1, temp2, ctx->schnorr_s, temp0));
1203 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1204 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1206 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1208 CHECK(d0_iobuf_write_bignum(out, temp2));
1211 // write the message itself
1213 CHECK(d0_iobuf_write_packet(out, message, msglen));
1215 return d0_iobuf_close(out, outbuflen);
1219 d0_iobuf_close(out, outbuflen);
1222 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_sign(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, const char *message, size_t msglen, char *outbuf, size_t *outbuflen)
1224 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 1, message, msglen, outbuf, outbuflen);
1226 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_sign_detached(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, const char *message, size_t msglen, char *outbuf, size_t *outbuflen)
1228 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 0, message, msglen, outbuf, outbuflen);
1231 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_verify_internal(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, D0_BOOL with_msg, const char *inbuf, size_t inbuflen, char *msg, size_t *msglen, D0_BOOL *status)
1233 d0_iobuf_t *in = NULL;
1234 d0_iobuf_t *conv = NULL;
1235 unsigned char *convbuf = NULL;
1236 unsigned char hashbuf[2048];
1239 USINGTEMPS(); // temps: 0 sig^e 2 g^s 3 g^-s 4 order
1242 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
1244 REPLACING(schnorr_G);
1250 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1253 USING(rsa_e); USING(rsa_n);
1255 in = d0_iobuf_open_read(inbuf, inbuflen);
1261 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
1262 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
1263 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
1265 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
1266 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
1267 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
1268 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
1269 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
1270 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
1272 // check signature of key (t = k^d, so, t^challenge = k)
1274 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1276 // we will actually sign SHA(4^s) to prevent a malleability attack!
1277 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1278 if(sz > sizeof(hashbuf))
1279 sz = sizeof(hashbuf);
1280 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1281 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1283 // + 7 / 8 is too large, so let's mod it
1284 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1287 if(d0_bignum_cmp(temp0, temp1))
1289 // accept the key anyway, but mark as failed signature! will later return 0 in status
1290 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
1294 CHECK(d0_dl_get_order(temp4, ctx->schnorr_G));
1295 CHECK(d0_iobuf_read_bignum(in, temp0)); // e == H(m || g^r)
1296 CHECK(d0_iobuf_read_bignum(in, temp1)); // x == (r - s*e) mod |G|
1298 CHECK(d0_iobuf_read_packet(in, msg, msglen));
1300 // VERIFY: g^x * (g^s)^-e = g^(x - s*e) = g^r
1302 // verify schnorr ID scheme
1303 // we need g^r = g^x (g^s)^e
1304 CHECK(d0_bignum_mod_pow(temp2, four, temp1, ctx->schnorr_G));
1305 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1306 CHECK(d0_bignum_mod_inv(temp3, ctx->schnorr_g_to_s, ctx->schnorr_G));
1307 CHECK(d0_bignum_mod_pow(temp1, temp3, temp0, ctx->schnorr_G));
1309 CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G));
1311 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); // temp3 now is g^r
1313 // hash it, hash it, everybody hash it
1314 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1315 CHECK(d0_iobuf_write_packet(conv, msg, *msglen));
1316 CHECK(d0_iobuf_write_bignum(conv, temp3));
1317 d0_iobuf_close(conv, &sz);
1319 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1322 CHECK(d0_bignum_import_unsigned(temp1, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1325 CHECK(!d0_bignum_cmp(temp0, temp1));
1329 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1331 d0_iobuf_close(in, NULL);
1336 d0_iobuf_close(in, NULL);
1339 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_verify(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, const char *inbuf, size_t inbuflen, char *msg, size_t *msglen, D0_BOOL *status)
1341 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 1, inbuf, inbuflen, msg, msglen, status);
1343 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_verify_detached(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, const char *inbuf, size_t inbuflen, const char *msg, size_t msglen, D0_BOOL *status)
1345 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 0, inbuf, inbuflen, (char *) msg, &msglen, status);
1348 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1350 d0_iobuf_t *out = NULL;
1351 unsigned char convbuf[1024];
1352 d0_iobuf_t *conv = NULL;
1358 USING(schnorr_g_to_s);
1360 out = d0_iobuf_open_write(outbuf, *outbuflen);
1361 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1363 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
1364 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
1365 CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_g_to_s));
1366 CHECK(d0_iobuf_close(conv, &sz));
1369 n = (*outbuflen / 4) * 3;
1370 if(n > SHA_DIGESTSIZE)
1372 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
1373 CHECK(d0_iobuf_conv_base64_out(out));
1375 return d0_iobuf_close(out, outbuflen);
1379 d0_iobuf_close(conv, &sz);
1380 d0_iobuf_close(out, outbuflen);
1384 D0_BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1388 USINGTEMPS(); // temps: temp0 result
1389 USING(t); USING(other_g_to_t); USING(schnorr_G);
1392 CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G));
1393 ret = d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen);
1402 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_verify_public_id(const d0_blind_id_t *ctx, D0_BOOL *status)
1404 unsigned char hashbuf[2048];
1407 USINGTEMPS(); // temps: temp0 temp1 temp2
1408 USING(schnorr_H_g_to_s_signature); USING(rsa_e); USING(rsa_n); USING(schnorr_g_to_s);
1410 if(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero))
1412 // check signature of key (t = k^d, so, t^challenge = k)
1415 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1417 // we will actually sign SHA(4^s) to prevent a malleability attack!
1418 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1419 if(sz > sizeof(hashbuf))
1420 sz = sizeof(hashbuf);
1421 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1422 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1424 // + 7 / 8 is too large, so let's mod it
1425 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1428 CHECK(d0_bignum_cmp(temp0, temp1) == 0);
1443 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_verify_private_id(const d0_blind_id_t *ctx)
1445 USINGTEMPS(); // temps: temp0 = g^s
1446 USING(schnorr_G); USING(schnorr_s); USING(schnorr_g_to_s);
1449 CHECK(d0_bignum_mod_pow(temp0, four, ctx->schnorr_s, ctx->schnorr_G));
1450 CHECK(!d0_bignum_cmp(temp0, ctx->schnorr_g_to_s));
1459 d0_blind_id_t *d0_blind_id_new(void)
1461 d0_blind_id_t *b = d0_malloc(sizeof(d0_blind_id_t));
1462 memset(b, 0, sizeof(*b));
1466 void d0_blind_id_free(d0_blind_id_t *a)
1468 d0_blind_id_clear(a);
1472 void d0_blind_id_util_sha256(char *out, const char *in, size_t n)
1475 SHA256_Init(&context);
1476 SHA256_Update(&context, (const unsigned char *) in, n);
1477 return SHA256_Final((unsigned char *) out, &context);
1480 void d0_blind_id_setmallocfuncs(d0_malloc_t *m, d0_free_t *f)
1482 d0_setmallocfuncs(m, f);
1484 void d0_blind_id_setmutexfuncs(d0_createmutex_t *c, d0_destroymutex_t *d, d0_lockmutex_t *l, d0_unlockmutex_t *u)
1486 d0_setmutexfuncs(c, d, l, u);