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)
123 tempmutex = d0_createmutex();
125 CHECK(d0_bignum_INITIALIZE());
126 CHECK_ASSIGN(zero, d0_bignum_int(zero, 0));
127 CHECK_ASSIGN(one, d0_bignum_int(one, 1));
128 CHECK_ASSIGN(four, d0_bignum_int(four, 4));
129 CHECK_ASSIGN(temp0, d0_bignum_int(temp0, 0));
130 CHECK_ASSIGN(temp1, d0_bignum_int(temp1, 0));
131 CHECK_ASSIGN(temp2, d0_bignum_int(temp2, 0));
132 CHECK_ASSIGN(temp3, d0_bignum_int(temp3, 0));
133 CHECK_ASSIGN(temp4, d0_bignum_int(temp4, 0));
141 void d0_blind_id_SHUTDOWN(void)
145 d0_bignum_free(zero);
147 d0_bignum_free(four);
148 d0_bignum_free(temp0);
149 d0_bignum_free(temp1);
150 d0_bignum_free(temp2);
151 d0_bignum_free(temp3);
152 d0_bignum_free(temp4);
153 d0_bignum_SHUTDOWN();
155 d0_destroymutex(tempmutex);
160 static d0_bignum_t *d0_dl_get_order(d0_bignum_t *o, const d0_bignum_t *G)
162 CHECK_ASSIGN(o, d0_bignum_sub(o, G, one));
163 CHECK(d0_bignum_shl(o, o, -1)); // order o = (G-1)/2
169 d0_bignum_t *d0_dl_get_from_order(d0_bignum_t *G, const d0_bignum_t *o)
171 CHECK_ASSIGN(G, d0_bignum_shl(G, o, 1));
172 CHECK(d0_bignum_add(G, G, one));
178 // temps must NOT be locked when calling this
179 static D0_BOOL d0_dl_generate_key(size_t size, d0_bignum_t *G)
181 USINGTEMPS(); // using: temp0
187 CHECK(d0_bignum_rand_bit_exact(temp0, size-1));
188 if(d0_bignum_isprime(temp0, 0) == 0)
190 CHECK(d0_dl_get_from_order(G, temp0));
191 if(d0_bignum_isprime(G, 10) == 0)
193 if(d0_bignum_isprime(temp0, 10) == 0) // finish the previous test
204 // temps must NOT be locked when calling this
205 static D0_BOOL d0_rsa_generate_key(size_t size, d0_blind_id_t *ctx)
207 USINGTEMPS(); // uses temp1 to temp4
210 int pb = (size + 1)/2;
217 // we use ctx->rsa_d for the first result so that we can unlock temps later
221 CHECK(d0_bignum_rand_bit_exact(ctx->rsa_d, pb));
222 if(d0_bignum_isprime(ctx->rsa_d, 10) == 0)
227 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one));
228 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
229 if(!d0_bignum_cmp(temp4, one))
241 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
242 if(!d0_bignum_cmp(temp1, ctx->rsa_d))
250 if(d0_bignum_isprime(temp1, 10) == 0)
255 CHECK(d0_bignum_sub(temp3, temp1, one));
256 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
257 if(!d0_bignum_cmp(temp4, one))
259 // we do NOT unlock, as we still need temp1 and temp3
268 // ctx->rsa_n = ctx->rsa_d*temp1
269 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
271 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
272 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
273 CHECK(d0_bignum_mul(temp0, temp2, temp3));
274 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
282 // temps must NOT be locked when calling this
283 static D0_BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass)
285 USINGTEMPS(); // uses temp1 to temp4
288 int pb = (size + 1)/2;
295 // we use ctx->rsa_d for the first result so that we can unlock temps later
299 CHECK(d0_bignum_rand_bit_exact(ctx->rsa_d, pb));
300 if(d0_bignum_isprime(ctx->rsa_d, 10) == 0)
305 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one));
306 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
307 if(!d0_bignum_cmp(temp4, one))
319 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
320 if(!d0_bignum_cmp(temp1, ctx->rsa_d))
329 // n = ctx->rsa_d*temp1
330 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
331 if(reject(ctx, pass))
337 if(d0_bignum_isprime(temp1, 10) == 0)
342 CHECK(d0_bignum_sub(temp3, temp1, one));
343 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
344 if(!d0_bignum_cmp(temp4, one))
346 // we do NOT unlock, as we still need temp3
355 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
356 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
357 CHECK(d0_bignum_mul(ctx->rsa_d, temp2, temp3));
358 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
366 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_destructive(unsigned char *convbuf, size_t sz, unsigned char *outbuf, size_t outbuflen)
372 while(n > SHA_DIGESTSIZE)
374 memcpy(outbuf, sha(shabuf, convbuf, sz), SHA_DIGESTSIZE);
375 outbuf += SHA_DIGESTSIZE;
377 for(i = 0; i < sz; ++i)
379 break; // stop until no carry
381 memcpy(outbuf, sha(shabuf, convbuf, sz), n);
385 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_bignum(const d0_bignum_t *in, unsigned char *outbuf, size_t outbuflen)
387 unsigned char convbuf[1024];
390 CHECK(d0_bignum_export_unsigned(in, convbuf, sizeof(convbuf)) >= 0);
391 sz = (d0_bignum_size(in) + 7) / 8;
392 CHECK(d0_longhash_destructive(convbuf, sz, outbuf, outbuflen));
399 void d0_blind_id_clear(d0_blind_id_t *ctx)
401 if(ctx->rsa_n) d0_bignum_free(ctx->rsa_n);
402 if(ctx->rsa_e) d0_bignum_free(ctx->rsa_e);
403 if(ctx->rsa_d) d0_bignum_free(ctx->rsa_d);
404 if(ctx->schnorr_G) d0_bignum_free(ctx->schnorr_G);
405 if(ctx->schnorr_s) d0_bignum_free(ctx->schnorr_s);
406 if(ctx->schnorr_g_to_s) d0_bignum_free(ctx->schnorr_g_to_s);
407 if(ctx->schnorr_H_g_to_s_signature) d0_bignum_free(ctx->schnorr_H_g_to_s_signature);
408 if(ctx->rsa_blind_signature_camouflage) d0_bignum_free(ctx->rsa_blind_signature_camouflage);
409 if(ctx->r) d0_bignum_free(ctx->r);
410 if(ctx->challenge) d0_bignum_free(ctx->challenge);
411 if(ctx->t) d0_bignum_free(ctx->t);
412 if(ctx->g_to_t) d0_bignum_free(ctx->g_to_t);
413 if(ctx->other_g_to_t) d0_bignum_free(ctx->other_g_to_t);
414 memset(ctx, 0, sizeof(*ctx));
417 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
419 d0_blind_id_clear(ctx);
420 if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n));
421 if(src->rsa_e) CHECK_ASSIGN(ctx->rsa_e, d0_bignum_mov(NULL, src->rsa_e));
422 if(src->rsa_d) CHECK_ASSIGN(ctx->rsa_d, d0_bignum_mov(NULL, src->rsa_d));
423 if(src->schnorr_G) CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_mov(NULL, src->schnorr_G));
424 if(src->schnorr_s) CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_mov(NULL, src->schnorr_s));
425 if(src->schnorr_g_to_s) CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mov(NULL, src->schnorr_g_to_s));
426 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));
427 if(src->rsa_blind_signature_camouflage) CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_mov(NULL, src->rsa_blind_signature_camouflage));
428 if(src->r) CHECK_ASSIGN(ctx->r, d0_bignum_mov(NULL, src->r));
429 if(src->challenge) CHECK_ASSIGN(ctx->challenge, d0_bignum_mov(NULL, src->challenge));
430 if(src->t) CHECK_ASSIGN(ctx->t, d0_bignum_mov(NULL, src->t));
431 if(src->g_to_t) CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mov(NULL, src->g_to_t));
432 if(src->other_g_to_t) CHECK_ASSIGN(ctx->other_g_to_t, d0_bignum_mov(NULL, src->other_g_to_t));
433 memcpy(ctx->msg, src->msg, sizeof(ctx->msg));
434 ctx->msglen = src->msglen;
435 memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash));
438 d0_blind_id_clear(ctx);
442 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)
444 REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
446 CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
447 CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
448 CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
450 CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
452 CHECK(d0_rsa_generate_key(k+1, ctx)); // must fit G for sure
458 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
460 return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL);
463 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
465 d0_iobuf_t *in = NULL;
467 REPLACING(rsa_n); REPLACING(rsa_e); REPLACING(rsa_d);
469 in = d0_iobuf_open_read(inbuf, inbuflen);
471 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
472 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
473 CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, ctx->rsa_d));
474 return d0_iobuf_close(in, NULL);
477 d0_iobuf_close(in, NULL);
481 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
483 d0_iobuf_t *in = NULL;
485 REPLACING(rsa_n); REPLACING(rsa_e);
487 in = d0_iobuf_open_read(inbuf, inbuflen);
488 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
489 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
490 return d0_iobuf_close(in, NULL);
493 d0_iobuf_close(in, NULL);
497 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
499 d0_iobuf_t *out = NULL;
501 USING(rsa_n); USING(rsa_e); USING(rsa_d);
503 out = d0_iobuf_open_write(outbuf, *outbuflen);
504 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
505 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
506 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_d));
507 return d0_iobuf_close(out, outbuflen);
510 d0_iobuf_close(out, outbuflen);
514 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
516 d0_iobuf_t *out = NULL;
518 USING(rsa_n); USING(rsa_e);
520 out = d0_iobuf_open_write(outbuf, *outbuflen);
521 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
522 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
523 return d0_iobuf_close(out, outbuflen);
526 if(!d0_iobuf_close(out, outbuflen))
531 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
533 d0_iobuf_t *out = NULL;
534 unsigned char convbuf[2048];
535 d0_iobuf_t *conv = NULL;
539 USING(rsa_n); USING(rsa_e);
541 out = d0_iobuf_open_write(outbuf, *outbuflen);
542 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
544 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
545 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
546 CHECK(d0_iobuf_close(conv, &sz));
549 n = (*outbuflen / 4) * 3;
550 if(n > SHA_DIGESTSIZE)
552 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
553 CHECK(d0_iobuf_conv_base64_out(out));
555 return d0_iobuf_close(out, outbuflen);
559 d0_iobuf_close(conv, &sz);
560 d0_iobuf_close(out, outbuflen);
564 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx)
567 REPLACING(schnorr_G);
569 CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_zero(ctx->schnorr_G));
570 CHECK(d0_dl_generate_key(d0_bignum_size(ctx->rsa_n)-1, ctx->schnorr_G));
576 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
578 d0_iobuf_t *in = NULL;
580 REPLACING(schnorr_G);
582 in = d0_iobuf_open_read(inbuf, inbuflen);
583 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
584 return d0_iobuf_close(in, NULL);
587 d0_iobuf_close(in, NULL);
591 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
593 d0_iobuf_t *out = NULL;
597 out = d0_iobuf_open_write(outbuf, *outbuflen);
598 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
599 return d0_iobuf_close(out, outbuflen);
602 d0_iobuf_close(out, outbuflen);
606 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx)
608 USINGTEMPS(); // temps: temp0 = order
610 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s);
613 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
614 CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_rand_range(ctx->schnorr_s, zero, temp0));
615 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mod_pow(ctx->schnorr_g_to_s, four, ctx->schnorr_s, ctx->schnorr_G));
616 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
625 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
627 d0_iobuf_t *out = NULL;
628 unsigned char hashbuf[2048];
631 USINGTEMPS(); // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge
632 USING(rsa_n); USING(rsa_e); USING(schnorr_g_to_s);
633 REPLACING(rsa_blind_signature_camouflage);
635 out = d0_iobuf_open_write(outbuf, *outbuflen);
637 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_rand_bit_atmost(ctx->rsa_blind_signature_camouflage, d0_bignum_size(ctx->rsa_n)));
638 CHECK(d0_bignum_mod_pow(temp0, ctx->rsa_blind_signature_camouflage, ctx->rsa_e, ctx->rsa_n));
640 // we will actually sign HA(4^s) to prevent a malleability attack!
642 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
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(temp2, 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 // check signature of key (t = k^d, so, t^challenge = k)
944 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
946 // we will actually sign SHA(4^s) to prevent a malleability attack!
947 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
948 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
949 if(sz > sizeof(hashbuf))
950 sz = sizeof(hashbuf);
951 CHECK(d0_longhash_bignum(temp2, hashbuf, sz));
952 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
954 // + 7 / 8 is too large, so let's mod it
955 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
958 if(d0_bignum_cmp(temp0, temp1))
960 // accept the key anyway, but mark as failed signature! will later return 0 in status
961 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
965 CHECK(d0_iobuf_read_raw(in, ctx->msghash, SCHNORR_HASHSIZE));
966 ctx->msglen = MSGSIZE;
967 CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen));
971 CHECK_ASSIGN(ctx->challenge, d0_bignum_int(ctx->challenge, 4)); // decided by fair dice roll
973 CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS));
975 CHECK(d0_iobuf_write_bignum(out, ctx->challenge));
977 // Diffie Hellmann send
979 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
981 CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll
983 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
985 CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G));
986 CHECK(d0_iobuf_write_bignum(out, temp0));
990 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
992 d0_iobuf_close(in, NULL);
993 return d0_iobuf_close(out, outbuflen);
997 d0_iobuf_close(in, NULL);
998 d0_iobuf_close(out, outbuflen);
1002 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)
1003 // 1. read challenge challenge of SCHNORR_BITS
1004 // 2. reply with r + s * challenge mod order
1006 d0_iobuf_t *in = NULL;
1007 d0_iobuf_t *out = NULL;
1009 USINGTEMPS(); // temps: 0 order, 1 prod, 2 y, 3 challenge
1010 REPLACING(other_g_to_t); REPLACING(t);
1011 USING(schnorr_G); USING(schnorr_s); USING(r); USING(g_to_t);
1013 in = d0_iobuf_open_read(inbuf, inbuflen);
1014 out = d0_iobuf_open_write(outbuf, *outbuflen);
1017 CHECK(d0_iobuf_read_bignum(in, temp3));
1018 CHECK(d0_bignum_cmp(temp3, zero) >= 0);
1019 CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS);
1021 // send response for schnorr ID scheme
1022 // i.challenge. r + ctx->schnorr_s * temp3
1023 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1024 CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_s, temp3, temp0));
1025 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1026 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1028 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1030 CHECK(d0_iobuf_write_bignum(out, temp2));
1033 // Diffie Hellmann recv
1034 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1035 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1036 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1037 // Diffie Hellmann send
1038 CHECK(d0_iobuf_write_bignum(out, ctx->g_to_t));
1040 d0_iobuf_close(in, NULL);
1041 return d0_iobuf_close(out, outbuflen);
1045 d0_iobuf_close(in, NULL);
1046 d0_iobuf_close(out, outbuflen);
1050 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)
1051 // 1. read y = r + s * challenge mod order
1052 // 2. verify: g^y (g^s)^-challenge = g^(r+s*challenge-s*challenge) = g^r
1053 // (check using H(g^r) which we know)
1055 d0_iobuf_t *in = NULL;
1056 unsigned char convbuf[1024];
1057 d0_iobuf_t *conv = NULL;
1061 USINGTEMPS(); // temps: 0 y 1 order
1062 USING(challenge); USING(schnorr_G);
1063 REPLACING(other_g_to_t);
1065 in = d0_iobuf_open_read(inbuf, inbuflen);
1069 CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
1070 CHECK(d0_iobuf_read_bignum(in, temp0));
1071 CHECK(d0_bignum_cmp(temp0, zero) >= 0);
1072 CHECK(d0_bignum_cmp(temp0, temp1) < 0);
1074 // verify schnorr ID scheme
1075 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1076 // we need 4^r = 4^temp0 (g^s)^-challenge
1077 CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G));
1078 CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G));
1080 // we need 4^r = 4^temp0 (g^s)^challenge
1081 CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_g_to_s, ctx->challenge, ctx->schnorr_G));
1083 CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G));
1084 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));
1086 // Diffie Hellmann recv
1087 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1088 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1089 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1091 // hash it, hash it, everybody hash it
1092 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1093 CHECK(d0_iobuf_write_bignum(conv, temp3));
1094 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1095 CHECK(d0_iobuf_write_packet(conv, ctx->msg, ctx->msglen));
1096 CHECK(d0_iobuf_write_bignum(conv, temp3));
1098 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1099 d0_iobuf_close(conv, &sz);
1101 if(memcmp(sha(shabuf, convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE))
1103 // FAIL (not owned by player)
1108 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1110 if(ctx->msglen <= *msglen)
1111 memcpy(msg, ctx->msg, ctx->msglen);
1113 memcpy(msg, ctx->msg, *msglen);
1114 *msglen = ctx->msglen;
1116 d0_iobuf_close(in, NULL);
1121 d0_iobuf_close(in, NULL);
1125 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx)
1128 unsigned char hashbuf[2048];
1130 USINGTEMPS(); // temps: 2 hash
1131 REPLACING(schnorr_H_g_to_s_signature);
1132 USING(schnorr_g_to_s); USING(rsa_d); USING(rsa_n);
1136 // we will actually sign SHA(4^s) to prevent a malleability attack!
1137 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1138 if(sz > sizeof(hashbuf))
1139 sz = sizeof(hashbuf);
1140 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1142 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1144 // + 7 / 8 is too large, so let's mod it
1145 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1146 CHECK(d0_bignum_mod_pow(ctx->schnorr_H_g_to_s_signature, temp1, ctx->rsa_d, ctx->rsa_n));
1156 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)
1158 d0_iobuf_t *out = NULL;
1159 unsigned char *convbuf = NULL;
1160 unsigned char hashbuf[2048];
1161 d0_iobuf_t *conv = NULL;
1164 USINGTEMPS(); // temps: 0 order 1 4^r 2 hash
1167 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1173 out = d0_iobuf_open_write(outbuf, *outbuflen);
1179 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
1180 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
1181 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
1184 // start schnorr SIGNATURE scheme
1185 // generate random number r; x = g^r; send hash of H(m||r), remember r, forget x
1187 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1188 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
1189 CHECK(d0_bignum_mod_pow(temp1, four, ctx->r, ctx->schnorr_G));
1191 // hash it, hash it, everybody hash it
1192 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1193 CHECK(d0_iobuf_write_packet(conv, message, msglen));
1194 CHECK(d0_iobuf_write_bignum(conv, temp1));
1195 d0_iobuf_close(conv, &sz);
1197 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1200 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1201 CHECK(d0_iobuf_write_bignum(out, temp2));
1203 // multiply with secret, sub k, modulo order
1204 CHECK(d0_bignum_mod_mul(temp1, temp2, ctx->schnorr_s, temp0));
1205 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1206 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1208 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1210 CHECK(d0_iobuf_write_bignum(out, temp2));
1213 // write the message itself
1215 CHECK(d0_iobuf_write_packet(out, message, msglen));
1217 return d0_iobuf_close(out, outbuflen);
1221 d0_iobuf_close(out, outbuflen);
1224 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)
1226 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 1, message, msglen, outbuf, outbuflen);
1228 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)
1230 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 0, message, msglen, outbuf, outbuflen);
1233 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)
1235 d0_iobuf_t *in = NULL;
1236 d0_iobuf_t *conv = NULL;
1237 unsigned char *convbuf = NULL;
1238 unsigned char hashbuf[2048];
1241 USINGTEMPS(); // temps: 0 sig^e 2 g^s 3 g^-s 4 order
1244 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
1246 REPLACING(schnorr_G);
1252 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1255 USING(rsa_e); USING(rsa_n);
1257 in = d0_iobuf_open_read(inbuf, inbuflen);
1263 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
1264 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
1265 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
1267 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
1268 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
1269 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
1270 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
1271 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
1272 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
1274 // check signature of key (t = k^d, so, t^challenge = k)
1276 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1278 // we will actually sign SHA(4^s) to prevent a malleability attack!
1279 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1280 if(sz > sizeof(hashbuf))
1281 sz = sizeof(hashbuf);
1282 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1283 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1285 // + 7 / 8 is too large, so let's mod it
1286 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1289 if(d0_bignum_cmp(temp0, temp1))
1291 // accept the key anyway, but mark as failed signature! will later return 0 in status
1292 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
1296 CHECK(d0_dl_get_order(temp4, ctx->schnorr_G));
1297 CHECK(d0_iobuf_read_bignum(in, temp0)); // e == H(m || g^r)
1298 CHECK(d0_iobuf_read_bignum(in, temp1)); // x == (r - s*e) mod |G|
1300 CHECK(d0_iobuf_read_packet(in, msg, msglen));
1302 // VERIFY: g^x * (g^s)^-e = g^(x - s*e) = g^r
1304 // verify schnorr ID scheme
1305 // we need g^r = g^x (g^s)^e
1306 CHECK(d0_bignum_mod_pow(temp2, four, temp1, ctx->schnorr_G));
1307 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1308 CHECK(d0_bignum_mod_inv(temp3, ctx->schnorr_g_to_s, ctx->schnorr_G));
1309 CHECK(d0_bignum_mod_pow(temp1, temp3, temp0, ctx->schnorr_G));
1311 CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G));
1313 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); // temp3 now is g^r
1315 // hash it, hash it, everybody hash it
1316 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1317 CHECK(d0_iobuf_write_packet(conv, msg, *msglen));
1318 CHECK(d0_iobuf_write_bignum(conv, temp3));
1319 d0_iobuf_close(conv, &sz);
1321 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1324 CHECK(d0_bignum_import_unsigned(temp1, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1327 CHECK(!d0_bignum_cmp(temp0, temp1));
1331 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1333 d0_iobuf_close(in, NULL);
1338 d0_iobuf_close(in, NULL);
1341 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)
1343 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 1, inbuf, inbuflen, msg, msglen, status);
1345 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)
1347 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 0, inbuf, inbuflen, (char *) msg, &msglen, status);
1350 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1352 d0_iobuf_t *out = NULL;
1353 unsigned char convbuf[1024];
1354 d0_iobuf_t *conv = NULL;
1360 USING(schnorr_g_to_s);
1362 out = d0_iobuf_open_write(outbuf, *outbuflen);
1363 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1365 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
1366 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
1367 CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_g_to_s));
1368 CHECK(d0_iobuf_close(conv, &sz));
1371 n = (*outbuflen / 4) * 3;
1372 if(n > SHA_DIGESTSIZE)
1374 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
1375 CHECK(d0_iobuf_conv_base64_out(out));
1377 return d0_iobuf_close(out, outbuflen);
1381 d0_iobuf_close(conv, &sz);
1382 d0_iobuf_close(out, outbuflen);
1386 D0_BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1390 USINGTEMPS(); // temps: temp0 result
1391 USING(t); USING(other_g_to_t); USING(schnorr_G);
1394 CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G));
1395 ret = d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen);
1404 d0_blind_id_t *d0_blind_id_new(void)
1406 d0_blind_id_t *b = d0_malloc(sizeof(d0_blind_id_t));
1407 memset(b, 0, sizeof(*b));
1411 void d0_blind_id_free(d0_blind_id_t *a)
1413 d0_blind_id_clear(a);
1417 void d0_blind_id_util_sha256(char *out, const char *in, size_t n)
1420 SHA256_Init(&context);
1421 SHA256_Update(&context, (const unsigned char *) in, n);
1422 return SHA256_Final((unsigned char *) out, &context);
1425 void d0_blind_id_setmallocfuncs(d0_malloc_t *m, d0_free_t *f)
1427 d0_setmallocfuncs(m, f);
1429 void d0_blind_id_setmutexfuncs(d0_createmutex_t *c, d0_destroymutex_t *d, d0_lockmutex_t *l, d0_unlockmutex_t *u)
1431 d0_setmutexfuncs(c, d, l, u);