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))
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
267 // ctx->rsa_n = ctx->rsa_d*temp1
268 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
270 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
271 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
272 CHECK(d0_bignum_mul(temp1, temp2, temp3));
273 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp1));
281 // temps must NOT be locked when calling this
282 static D0_BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass)
284 USINGTEMPS(); // uses temp1 to temp4
287 int pb = (size + 1)/2;
294 // we use ctx->rsa_d for the first result so that we can unlock temps later
298 CHECK(d0_bignum_rand_bit_exact(ctx->rsa_d, pb));
299 if(d0_bignum_isprime(ctx->rsa_d, 10) == 0)
304 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one));
305 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
306 if(!d0_bignum_cmp(temp4, one))
317 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
318 if(!d0_bignum_cmp(temp1, ctx->rsa_d))
327 // n = ctx->rsa_d*temp1
328 CHECK(d0_bignum_mul(ctx->rsa_n, ctx->rsa_d, temp1));
329 if(reject(ctx, pass))
335 if(d0_bignum_isprime(temp1, 10) == 0)
340 CHECK(d0_bignum_sub(temp3, temp1, one));
341 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
342 if(!d0_bignum_cmp(temp4, one))
344 // we do NOT unlock, as we still need temp3
352 // ctx->rsa_d = ctx->rsa_e^-1 mod (ctx->rsa_d-1)(temp1-1)
353 CHECK(d0_bignum_sub(temp2, ctx->rsa_d, one)); // we can't reuse the value from above because temps were unlocked
354 CHECK(d0_bignum_mul(temp1, temp2, temp3));
355 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp1));
363 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_destructive(unsigned char *convbuf, size_t sz, unsigned char *outbuf, size_t outbuflen)
369 while(n > SHA_DIGESTSIZE)
371 memcpy(outbuf, sha(shabuf, convbuf, sz), SHA_DIGESTSIZE);
372 outbuf += SHA_DIGESTSIZE;
374 for(i = 0; i < sz; ++i)
376 break; // stop until no carry
378 memcpy(outbuf, sha(shabuf, convbuf, sz), n);
382 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_bignum(const d0_bignum_t *in, unsigned char *outbuf, size_t outbuflen)
384 unsigned char convbuf[1024];
387 CHECK(d0_bignum_export_unsigned(in, convbuf, sizeof(convbuf)) >= 0);
388 sz = (d0_bignum_size(in) + 7) / 8;
389 CHECK(d0_longhash_destructive(convbuf, sz, outbuf, outbuflen));
396 void d0_blind_id_clear(d0_blind_id_t *ctx)
398 if(ctx->rsa_n) d0_bignum_free(ctx->rsa_n);
399 if(ctx->rsa_e) d0_bignum_free(ctx->rsa_e);
400 if(ctx->rsa_d) d0_bignum_free(ctx->rsa_d);
401 if(ctx->schnorr_G) d0_bignum_free(ctx->schnorr_G);
402 if(ctx->schnorr_s) d0_bignum_free(ctx->schnorr_s);
403 if(ctx->schnorr_g_to_s) d0_bignum_free(ctx->schnorr_g_to_s);
404 if(ctx->schnorr_H_g_to_s_signature) d0_bignum_free(ctx->schnorr_H_g_to_s_signature);
405 if(ctx->rsa_blind_signature_camouflage) d0_bignum_free(ctx->rsa_blind_signature_camouflage);
406 if(ctx->r) d0_bignum_free(ctx->r);
407 if(ctx->challenge) d0_bignum_free(ctx->challenge);
408 if(ctx->t) d0_bignum_free(ctx->t);
409 if(ctx->g_to_t) d0_bignum_free(ctx->g_to_t);
410 if(ctx->other_g_to_t) d0_bignum_free(ctx->other_g_to_t);
411 memset(ctx, 0, sizeof(*ctx));
414 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
416 d0_blind_id_clear(ctx);
417 if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n));
418 if(src->rsa_e) CHECK_ASSIGN(ctx->rsa_e, d0_bignum_mov(NULL, src->rsa_e));
419 if(src->rsa_d) CHECK_ASSIGN(ctx->rsa_d, d0_bignum_mov(NULL, src->rsa_d));
420 if(src->schnorr_G) CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_mov(NULL, src->schnorr_G));
421 if(src->schnorr_s) CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_mov(NULL, src->schnorr_s));
422 if(src->schnorr_g_to_s) CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mov(NULL, src->schnorr_g_to_s));
423 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));
424 if(src->rsa_blind_signature_camouflage) CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_mov(NULL, src->rsa_blind_signature_camouflage));
425 if(src->r) CHECK_ASSIGN(ctx->r, d0_bignum_mov(NULL, src->r));
426 if(src->challenge) CHECK_ASSIGN(ctx->challenge, d0_bignum_mov(NULL, src->challenge));
427 if(src->t) CHECK_ASSIGN(ctx->t, d0_bignum_mov(NULL, src->t));
428 if(src->g_to_t) CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mov(NULL, src->g_to_t));
429 if(src->other_g_to_t) CHECK_ASSIGN(ctx->other_g_to_t, d0_bignum_mov(NULL, src->other_g_to_t));
430 memcpy(ctx->msg, src->msg, sizeof(ctx->msg));
431 ctx->msglen = src->msglen;
432 memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash));
435 d0_blind_id_clear(ctx);
439 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)
441 REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
443 CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
444 CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
445 CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
447 CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
449 CHECK(d0_rsa_generate_key(k+1, ctx)); // must fit G for sure
455 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
457 return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL);
460 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
462 d0_iobuf_t *in = NULL;
464 REPLACING(rsa_n); REPLACING(rsa_e); REPLACING(rsa_d);
466 in = d0_iobuf_open_read(inbuf, inbuflen);
468 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
469 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
470 CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, ctx->rsa_d));
471 return d0_iobuf_close(in, NULL);
474 d0_iobuf_close(in, NULL);
478 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
480 d0_iobuf_t *in = NULL;
482 REPLACING(rsa_n); REPLACING(rsa_e);
484 in = d0_iobuf_open_read(inbuf, inbuflen);
485 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
486 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
487 return d0_iobuf_close(in, NULL);
490 d0_iobuf_close(in, NULL);
494 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
496 d0_iobuf_t *out = NULL;
498 USING(rsa_n); USING(rsa_e); USING(rsa_d);
500 out = d0_iobuf_open_write(outbuf, *outbuflen);
501 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
502 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
503 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_d));
504 return d0_iobuf_close(out, outbuflen);
507 d0_iobuf_close(out, outbuflen);
511 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
513 d0_iobuf_t *out = NULL;
515 USING(rsa_n); USING(rsa_e);
517 out = d0_iobuf_open_write(outbuf, *outbuflen);
518 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
519 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
520 return d0_iobuf_close(out, outbuflen);
523 if(!d0_iobuf_close(out, outbuflen))
528 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
530 d0_iobuf_t *out = NULL;
531 unsigned char convbuf[2048];
532 d0_iobuf_t *conv = NULL;
536 USING(rsa_n); USING(rsa_e);
538 out = d0_iobuf_open_write(outbuf, *outbuflen);
539 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
541 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
542 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
543 CHECK(d0_iobuf_close(conv, &sz));
546 n = (*outbuflen / 4) * 3;
547 if(n > SHA_DIGESTSIZE)
549 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
550 CHECK(d0_iobuf_conv_base64_out(out));
552 return d0_iobuf_close(out, outbuflen);
556 d0_iobuf_close(conv, &sz);
557 d0_iobuf_close(out, outbuflen);
561 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx)
564 REPLACING(schnorr_G);
566 CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_zero(ctx->schnorr_G));
567 CHECK(d0_dl_generate_key(d0_bignum_size(ctx->rsa_n)-1, ctx->schnorr_G));
573 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
575 d0_iobuf_t *in = NULL;
577 REPLACING(schnorr_G);
579 in = d0_iobuf_open_read(inbuf, inbuflen);
580 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
581 return d0_iobuf_close(in, NULL);
584 d0_iobuf_close(in, NULL);
588 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
590 d0_iobuf_t *out = NULL;
594 out = d0_iobuf_open_write(outbuf, *outbuflen);
595 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
596 return d0_iobuf_close(out, outbuflen);
599 d0_iobuf_close(out, outbuflen);
603 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx)
605 USINGTEMPS(); // temps: temp0 = order
607 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s);
610 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
611 CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_rand_range(ctx->schnorr_s, zero, temp0));
612 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mod_pow(ctx->schnorr_g_to_s, four, ctx->schnorr_s, ctx->schnorr_G));
613 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
622 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
624 d0_iobuf_t *out = NULL;
625 unsigned char hashbuf[2048];
628 USINGTEMPS(); // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge
629 USING(rsa_n); USING(rsa_e); USING(schnorr_g_to_s);
630 REPLACING(rsa_blind_signature_camouflage);
632 out = d0_iobuf_open_write(outbuf, *outbuflen);
634 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_rand_bit_atmost(ctx->rsa_blind_signature_camouflage, d0_bignum_size(ctx->rsa_n)));
635 CHECK(d0_bignum_mod_pow(temp0, ctx->rsa_blind_signature_camouflage, ctx->rsa_e, ctx->rsa_n));
637 // we will actually sign HA(4^s) to prevent a malleability attack!
639 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
640 if(sz > sizeof(hashbuf))
641 sz = sizeof(hashbuf);
642 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
643 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
646 CHECK(d0_bignum_mod_mul(temp1, temp2, temp0, ctx->rsa_n));
647 CHECK(d0_iobuf_write_bignum(out, temp1));
649 return d0_iobuf_close(out, outbuflen);
653 d0_iobuf_close(out, outbuflen);
657 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)
659 d0_iobuf_t *in = NULL;
660 d0_iobuf_t *out = NULL;
662 USINGTEMPS(); // temps: temp0 input, temp1 temp0^d
663 USING(rsa_d); USING(rsa_n);
665 in = d0_iobuf_open_read(inbuf, inbuflen);
666 out = d0_iobuf_open_write(outbuf, *outbuflen);
669 CHECK(d0_iobuf_read_bignum(in, temp0));
670 CHECK(d0_bignum_mod_pow(temp1, temp0, ctx->rsa_d, ctx->rsa_n));
671 CHECK(d0_iobuf_write_bignum(out, temp1));
674 d0_iobuf_close(in, NULL);
675 return d0_iobuf_close(out, outbuflen);
679 d0_iobuf_close(in, NULL);
680 d0_iobuf_close(out, outbuflen);
684 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
686 d0_iobuf_t *in = NULL;
688 USINGTEMPS(); // temps: temp0 input, temp1 rsa_blind_signature_camouflage^-1
689 USING(rsa_blind_signature_camouflage); USING(rsa_n);
690 REPLACING(schnorr_H_g_to_s_signature);
692 in = d0_iobuf_open_read(inbuf, inbuflen);
696 CHECK(d0_iobuf_read_bignum(in, temp0));
697 CHECK(d0_bignum_mod_inv(temp1, ctx->rsa_blind_signature_camouflage, ctx->rsa_n));
698 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));
701 return d0_iobuf_close(in, NULL);
705 d0_iobuf_close(in, NULL);
709 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)
711 d0_iobuf_t *in = NULL;
713 REPLACING(rsa_blind_signature_camouflage);
715 in = d0_iobuf_open_read(inbuf, inbuflen);
717 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_iobuf_read_bignum(in, ctx->rsa_blind_signature_camouflage));
719 return d0_iobuf_close(in, NULL);
722 d0_iobuf_close(in, NULL);
726 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)
728 d0_iobuf_t *out = NULL;
730 USING(rsa_blind_signature_camouflage);
732 out = d0_iobuf_open_write(outbuf, *outbuflen);
734 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_blind_signature_camouflage));
736 return d0_iobuf_close(out, outbuflen);
739 d0_iobuf_close(out, outbuflen);
743 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
745 d0_iobuf_t *in = NULL;
747 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
749 in = d0_iobuf_open_read(inbuf, inbuflen);
751 CHECK_ASSIGN(ctx->schnorr_s, d0_iobuf_read_bignum(in, ctx->schnorr_s));
752 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
753 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
755 return d0_iobuf_close(in, NULL);
758 d0_iobuf_close(in, NULL);
762 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
764 d0_iobuf_t *in = NULL;
766 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
768 in = d0_iobuf_open_read(inbuf, inbuflen);
770 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
771 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
773 return d0_iobuf_close(in, NULL);
776 d0_iobuf_close(in, NULL);
780 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
782 d0_iobuf_t *out = NULL;
784 USING(schnorr_s); USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
786 out = d0_iobuf_open_write(outbuf, *outbuflen);
788 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_s));
789 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
790 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
792 return d0_iobuf_close(out, outbuflen);
795 d0_iobuf_close(out, outbuflen);
799 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
801 d0_iobuf_t *out = NULL;
803 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
805 out = d0_iobuf_open_write(outbuf, *outbuflen);
807 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
808 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
810 return d0_iobuf_close(out, outbuflen);
813 d0_iobuf_close(out, outbuflen);
817 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)
819 // first run: send 4^s, 4^s signature
820 // 1. get random r, send HASH(4^r)
822 d0_iobuf_t *out = NULL;
823 unsigned char convbuf[1024];
824 d0_iobuf_t *conv = NULL;
829 USINGTEMPS(); // temps: temp0 order, temp0 4^r
832 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
835 REPLACING(r); REPLACING(t); REPLACING(g_to_t);
837 out = d0_iobuf_open_write(outbuf, *outbuflen);
843 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
844 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
845 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
848 // start schnorr ID scheme
849 // generate random number r; x = g^r; send hash of x, remember r, forget x
851 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
853 CHECK_ASSIGN(ctx->r, d0_bignum_int(ctx->r, 4)); // decided by fair dice roll
855 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
858 // initialize Signed Diffie Hellmann
859 // we already have the group order in temp1
861 CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll
863 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
865 // can we SOMEHOW do this with just one mod_pow?
867 CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G));
868 CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G));
871 // hash it, hash it, everybody hash it
872 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
873 CHECK(d0_iobuf_write_bignum(conv, temp0));
874 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
875 CHECK(d0_iobuf_write_packet(conv, msg, msglen));
876 CHECK(d0_iobuf_write_bignum(conv, temp0));
878 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
879 d0_iobuf_close(conv, &sz);
881 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), SCHNORR_HASHSIZE) == SCHNORR_HASHSIZE);
882 CHECK(d0_iobuf_write_packet(out, msg, msglen));
884 return d0_iobuf_close(out, outbuflen);
888 d0_iobuf_close(out, outbuflen);
892 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)
893 // first run: get 4^s, 4^s signature
896 // 3. send challenge challenge of SCHNORR_BITS
898 d0_iobuf_t *in = NULL;
899 d0_iobuf_t *out = NULL;
900 unsigned char hashbuf[2048];
903 USINGTEMPS(); // temps: temp0 order, temp0 signature check
906 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
908 REPLACING(schnorr_G);
914 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
917 USING(rsa_e); USING(rsa_n);
918 REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); REPLACING(t);
920 in = d0_iobuf_open_read(inbuf, inbuflen);
921 out = d0_iobuf_open_write(outbuf, *outbuflen);
927 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
928 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
929 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
931 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
932 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
933 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
934 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
935 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
936 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
938 if(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero))
940 // check signature of key (t = k^d, so, t^challenge = k)
942 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
944 // we will actually sign SHA(4^s) to prevent a malleability attack!
945 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
946 if(sz > sizeof(hashbuf))
947 sz = sizeof(hashbuf);
948 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
949 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
951 // + 7 / 8 is too large, so let's mod it
952 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
955 CHECK(d0_bignum_cmp(temp0, temp1) == 0);
959 CHECK(d0_iobuf_read_raw(in, ctx->msghash, SCHNORR_HASHSIZE));
960 ctx->msglen = MSGSIZE;
961 CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen));
965 CHECK_ASSIGN(ctx->challenge, d0_bignum_int(ctx->challenge, 4)); // decided by fair dice roll
967 CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS));
969 CHECK(d0_iobuf_write_bignum(out, ctx->challenge));
971 // Diffie Hellmann send
973 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
975 CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll
977 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
979 CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G));
980 CHECK(d0_iobuf_write_bignum(out, temp0));
984 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
986 d0_iobuf_close(in, NULL);
987 return d0_iobuf_close(out, outbuflen);
991 d0_iobuf_close(in, NULL);
992 d0_iobuf_close(out, outbuflen);
996 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)
997 // 1. read challenge challenge of SCHNORR_BITS
998 // 2. reply with r + s * challenge mod order
1000 d0_iobuf_t *in = NULL;
1001 d0_iobuf_t *out = NULL;
1003 USINGTEMPS(); // temps: 0 order, 1 prod, 2 y, 3 challenge
1004 REPLACING(other_g_to_t); REPLACING(t);
1005 USING(schnorr_G); USING(schnorr_s); USING(r); USING(g_to_t);
1007 in = d0_iobuf_open_read(inbuf, inbuflen);
1008 out = d0_iobuf_open_write(outbuf, *outbuflen);
1011 CHECK(d0_iobuf_read_bignum(in, temp3));
1012 CHECK(d0_bignum_cmp(temp3, zero) >= 0);
1013 CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS);
1015 // send response for schnorr ID scheme
1016 // i.challenge. r + ctx->schnorr_s * temp3
1017 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1018 CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_s, temp3, temp0));
1019 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1020 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1022 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1024 CHECK(d0_iobuf_write_bignum(out, temp2));
1027 // Diffie Hellmann recv
1028 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1029 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1030 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1031 // Diffie Hellmann send
1032 CHECK(d0_iobuf_write_bignum(out, ctx->g_to_t));
1034 d0_iobuf_close(in, NULL);
1035 return d0_iobuf_close(out, outbuflen);
1039 d0_iobuf_close(in, NULL);
1040 d0_iobuf_close(out, outbuflen);
1044 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)
1045 // 1. read y = r + s * challenge mod order
1046 // 2. verify: g^y (g^s)^-challenge = g^(r+s*challenge-s*challenge) = g^r
1047 // (check using H(g^r) which we know)
1049 d0_iobuf_t *in = NULL;
1050 unsigned char convbuf[1024];
1051 d0_iobuf_t *conv = NULL;
1055 USINGTEMPS(); // temps: 0 y 1 order
1056 USING(challenge); USING(schnorr_G);
1057 REPLACING(other_g_to_t);
1059 in = d0_iobuf_open_read(inbuf, inbuflen);
1063 CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
1064 CHECK(d0_iobuf_read_bignum(in, temp0));
1065 CHECK(d0_bignum_cmp(temp0, zero) >= 0);
1066 CHECK(d0_bignum_cmp(temp0, temp1) < 0);
1068 // verify schnorr ID scheme
1069 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1070 // we need 4^r = 4^temp0 (g^s)^-challenge
1071 CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G));
1072 CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G));
1074 // we need 4^r = 4^temp0 (g^s)^challenge
1075 CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_g_to_s, ctx->challenge, ctx->schnorr_G));
1077 CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G));
1078 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));
1080 // Diffie Hellmann recv
1081 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
1082 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
1083 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
1085 // hash it, hash it, everybody hash it
1086 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1087 CHECK(d0_iobuf_write_bignum(conv, temp3));
1088 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1089 CHECK(d0_iobuf_write_packet(conv, ctx->msg, ctx->msglen));
1090 CHECK(d0_iobuf_write_bignum(conv, temp3));
1092 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
1093 d0_iobuf_close(conv, &sz);
1095 if(memcmp(sha(shabuf, convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE))
1097 // FAIL (not owned by player)
1102 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1104 if(ctx->msglen <= *msglen)
1105 memcpy(msg, ctx->msg, ctx->msglen);
1107 memcpy(msg, ctx->msg, *msglen);
1108 *msglen = ctx->msglen;
1110 d0_iobuf_close(in, NULL);
1115 d0_iobuf_close(in, NULL);
1119 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx)
1122 unsigned char hashbuf[2048];
1124 USINGTEMPS(); // temps: 2 hash
1125 REPLACING(schnorr_H_g_to_s_signature);
1126 USING(schnorr_g_to_s); USING(rsa_d); USING(rsa_n);
1130 // we will actually sign SHA(4^s) to prevent a malleability attack!
1131 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1132 if(sz > sizeof(hashbuf))
1133 sz = sizeof(hashbuf);
1134 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1136 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1138 // + 7 / 8 is too large, so let's mod it
1139 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1140 CHECK(d0_bignum_mod_pow(ctx->schnorr_H_g_to_s_signature, temp1, ctx->rsa_d, ctx->rsa_n));
1150 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)
1152 d0_iobuf_t *out = NULL;
1153 unsigned char *convbuf = NULL;
1154 unsigned char hashbuf[2048];
1155 d0_iobuf_t *conv = NULL;
1158 USINGTEMPS(); // temps: 0 order 1 4^r 2 hash
1161 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1167 out = d0_iobuf_open_write(outbuf, *outbuflen);
1173 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
1174 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
1175 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
1178 // start schnorr SIGNATURE scheme
1179 // generate random number r; x = g^r; send hash of H(m||r), remember r, forget x
1181 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1182 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
1183 CHECK(d0_bignum_mod_pow(temp1, four, ctx->r, ctx->schnorr_G));
1185 // hash it, hash it, everybody hash it
1186 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1187 CHECK(d0_iobuf_write_packet(conv, message, msglen));
1188 CHECK(d0_iobuf_write_bignum(conv, temp1));
1189 d0_iobuf_close(conv, &sz);
1191 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1194 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, (d0_bignum_size(temp0) + 7) / 8));
1195 CHECK(d0_iobuf_write_bignum(out, temp2));
1197 // multiply with secret, sub k, modulo order
1198 CHECK(d0_bignum_mod_mul(temp1, temp2, ctx->schnorr_s, temp0));
1199 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1200 CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0));
1202 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1204 CHECK(d0_iobuf_write_bignum(out, temp2));
1207 // write the message itself
1209 CHECK(d0_iobuf_write_packet(out, message, msglen));
1211 return d0_iobuf_close(out, outbuflen);
1215 d0_iobuf_close(out, outbuflen);
1218 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)
1220 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 1, message, msglen, outbuf, outbuflen);
1222 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)
1224 return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 0, message, msglen, outbuf, outbuflen);
1227 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)
1229 d0_iobuf_t *in = NULL;
1230 d0_iobuf_t *conv = NULL;
1231 unsigned char *convbuf = NULL;
1232 unsigned char hashbuf[2048];
1235 USINGTEMPS(); // temps: 0 sig^e 2 g^s 3 g^-s 4 order
1238 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
1240 REPLACING(schnorr_G);
1246 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1249 USING(rsa_e); USING(rsa_n);
1251 in = d0_iobuf_open_read(inbuf, inbuflen);
1257 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
1258 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
1259 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
1261 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
1262 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
1263 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
1264 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
1265 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
1266 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
1268 // check signature of key (t = k^d, so, t^challenge = k)
1270 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1272 // we will actually sign SHA(4^s) to prevent a malleability attack!
1273 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1274 if(sz > sizeof(hashbuf))
1275 sz = sizeof(hashbuf);
1276 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1277 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1279 // + 7 / 8 is too large, so let's mod it
1280 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1283 if(d0_bignum_cmp(temp0, temp1))
1285 // accept the key anyway, but mark as failed signature! will later return 0 in status
1286 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
1290 CHECK(d0_dl_get_order(temp4, ctx->schnorr_G));
1291 CHECK(d0_iobuf_read_bignum(in, temp0)); // e == H(m || g^r)
1292 CHECK(d0_iobuf_read_bignum(in, temp1)); // x == (r - s*e) mod |G|
1294 CHECK(d0_iobuf_read_packet(in, msg, msglen));
1296 // VERIFY: g^x * (g^s)^-e = g^(x - s*e) = g^r
1298 // verify schnorr ID scheme
1299 // we need g^r = g^x (g^s)^e
1300 CHECK(d0_bignum_mod_pow(temp2, four, temp1, ctx->schnorr_G));
1301 #ifdef D0_BLIND_ID_POSITIVE_PROTOCOL
1302 CHECK(d0_bignum_mod_inv(temp3, ctx->schnorr_g_to_s, ctx->schnorr_G));
1303 CHECK(d0_bignum_mod_pow(temp1, temp3, temp0, ctx->schnorr_G));
1305 CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G));
1307 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); // temp3 now is g^r
1309 // hash it, hash it, everybody hash it
1310 conv = d0_iobuf_open_write_p((void **) &convbuf, 0);
1311 CHECK(d0_iobuf_write_packet(conv, msg, *msglen));
1312 CHECK(d0_iobuf_write_bignum(conv, temp3));
1313 d0_iobuf_close(conv, &sz);
1315 CHECK(d0_longhash_destructive(convbuf, sz, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1318 CHECK(d0_bignum_import_unsigned(temp1, hashbuf, (d0_bignum_size(temp4) + 7) / 8));
1321 CHECK(!d0_bignum_cmp(temp0, temp1));
1325 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1327 d0_iobuf_close(in, NULL);
1332 d0_iobuf_close(in, NULL);
1335 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)
1337 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 1, inbuf, inbuflen, msg, msglen, status);
1339 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)
1341 return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 0, inbuf, inbuflen, (char *) msg, &msglen, status);
1344 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1346 d0_iobuf_t *out = NULL;
1347 unsigned char convbuf[1024];
1348 d0_iobuf_t *conv = NULL;
1354 USING(schnorr_g_to_s);
1356 out = d0_iobuf_open_write(outbuf, *outbuflen);
1357 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1359 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
1360 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
1361 CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_g_to_s));
1362 CHECK(d0_iobuf_close(conv, &sz));
1365 n = (*outbuflen / 4) * 3;
1366 if(n > SHA_DIGESTSIZE)
1368 CHECK(d0_iobuf_write_raw(out, sha(shabuf, convbuf, sz), n) == n);
1369 CHECK(d0_iobuf_conv_base64_out(out));
1371 return d0_iobuf_close(out, outbuflen);
1375 d0_iobuf_close(conv, &sz);
1376 d0_iobuf_close(out, outbuflen);
1380 D0_BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1384 USINGTEMPS(); // temps: temp0 result
1385 USING(t); USING(other_g_to_t); USING(schnorr_G);
1388 CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G));
1389 ret = d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen);
1398 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_verify_public_id(const d0_blind_id_t *ctx, D0_BOOL *status)
1400 unsigned char hashbuf[2048];
1403 USINGTEMPS(); // temps: temp0 temp1 temp2
1404 USING(schnorr_H_g_to_s_signature); USING(rsa_e); USING(rsa_n); USING(schnorr_g_to_s);
1406 if(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero))
1408 // check signature of key (t = k^d, so, t^challenge = k)
1411 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1413 // we will actually sign SHA(4^s) to prevent a malleability attack!
1414 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1415 if(sz > sizeof(hashbuf))
1416 sz = sizeof(hashbuf);
1417 CHECK(d0_longhash_bignum(ctx->schnorr_g_to_s, hashbuf, sz));
1418 CHECK(d0_bignum_import_unsigned(temp2, hashbuf, sz));
1420 // + 7 / 8 is too large, so let's mod it
1421 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1424 CHECK(d0_bignum_cmp(temp0, temp1) == 0);
1439 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_verify_private_id(const d0_blind_id_t *ctx)
1441 USINGTEMPS(); // temps: temp0 = g^s
1442 USING(schnorr_G); USING(schnorr_s); USING(schnorr_g_to_s);
1445 CHECK(d0_bignum_mod_pow(temp0, four, ctx->schnorr_s, ctx->schnorr_G));
1446 CHECK(!d0_bignum_cmp(temp0, ctx->schnorr_g_to_s));
1455 d0_blind_id_t *d0_blind_id_new(void)
1457 d0_blind_id_t *b = d0_malloc(sizeof(d0_blind_id_t));
1458 memset(b, 0, sizeof(*b));
1462 void d0_blind_id_free(d0_blind_id_t *a)
1464 d0_blind_id_clear(a);
1468 void d0_blind_id_util_sha256(char *out, const char *in, size_t n)
1471 SHA256_Init(&context);
1472 SHA256_Update(&context, (const unsigned char *) in, n);
1473 return SHA256_Final((unsigned char *) out, &context);
1476 void d0_blind_id_setmallocfuncs(d0_malloc_t *m, d0_free_t *f)
1478 d0_setmallocfuncs(m, f);
1480 void d0_blind_id_setmutexfuncs(d0_createmutex_t *c, d0_destroymutex_t *d, d0_lockmutex_t *l, d0_unlockmutex_t *u)
1482 d0_setmutexfuncs(c, d, l, u);