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"
44 #define SHA_DIGESTSIZE 32
45 const char *sha(const unsigned char *in, size_t len)
48 d0_blind_id_util_sha256(h, (const char *) in, len);
52 // for zero knowledge, we need multiple instances of schnorr ID scheme... should normally be sequential
53 // parallel schnorr ID is not provably zero knowledge :(
54 // (evil verifier can know all questions in advance, so sequential is disadvantage for him)
55 // we'll just live with a 1:1048576 chance of cheating, and support reauthenticating
57 #define SCHNORR_BITS 20
58 // probability of cheat: 2^(-bits+1)
60 #define SCHNORR_HASHSIZE SHA_DIGESTSIZE
61 // cannot be >= SHA_DIGESTSIZE
62 // *8 must be >= SCHNORR_BITS
63 // no need to save bits here
65 #define MSGSIZE 640 // ought to be enough for anyone
69 // signing (Xonotic pub and priv key)
70 d0_bignum_t *rsa_n, *rsa_e, *rsa_d;
72 // public data (Schnorr ID)
73 d0_bignum_t *schnorr_G;
75 // private data (player ID private key)
76 d0_bignum_t *schnorr_s;
78 // public data (player ID public key, this is what the server gets to know)
79 d0_bignum_t *schnorr_g_to_s;
80 d0_bignum_t *schnorr_H_g_to_s_signature; // 0 when signature is invalid
81 // as hash function H, we get the SHA1 and reinterpret as bignum - yes, it always is < 160 bits
84 d0_bignum_t *rsa_blind_signature_camouflage; // random number blind signature
86 d0_bignum_t *r; // random number for schnorr ID
87 d0_bignum_t *t; // for DH key exchange
88 d0_bignum_t *g_to_t; // for DH key exchange
89 d0_bignum_t *other_g_to_t; // for DH key exchange
90 d0_bignum_t *challenge; // challenge
92 char msghash[SCHNORR_HASHSIZE]; // init hash
93 char msg[MSGSIZE]; // message
94 size_t msglen; // message length
97 #define CHECK(x) do { if(!(x)) goto fail; } while(0)
98 #define CHECK_ASSIGN(var, value) do { d0_bignum_t *val; val = value; if(!val) goto fail; var = val; } while(0)
99 #define MPCHECK(x) do { if(!failed) if(!(x)) failed = 1; } while(0)
100 #define MPCHECK_ASSIGN(var, value) do { if(!failed) { d0_bignum_t *val; val = value; if(val) var = val; else failed = 1; } } while(0)
102 #define USING(x) if(!(ctx->x)) return 0
105 static d0_bignum_t *zero, *one, *four, *temp0, *temp1, *temp2, *temp3, *temp4;
107 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_INITIALIZE(void)
109 CHECK(d0_bignum_INITIALIZE());
110 CHECK_ASSIGN(zero, d0_bignum_int(zero, 0));
111 CHECK_ASSIGN(one, d0_bignum_int(one, 1));
112 CHECK_ASSIGN(four, d0_bignum_int(four, 4));
113 CHECK_ASSIGN(temp0, d0_bignum_int(temp0, 0));
114 CHECK_ASSIGN(temp1, d0_bignum_int(temp1, 0));
115 CHECK_ASSIGN(temp2, d0_bignum_int(temp2, 0));
116 CHECK_ASSIGN(temp3, d0_bignum_int(temp3, 0));
117 CHECK_ASSIGN(temp4, d0_bignum_int(temp4, 0));
123 void d0_blind_id_SHUTDOWN(void)
125 d0_bignum_free(zero);
127 d0_bignum_free(four);
128 d0_bignum_free(temp0);
129 d0_bignum_free(temp1);
130 d0_bignum_free(temp2);
131 d0_bignum_free(temp3);
132 d0_bignum_free(temp4);
133 d0_bignum_SHUTDOWN();
137 d0_bignum_t *d0_dl_get_order(d0_bignum_t *o, const d0_bignum_t *G)
139 CHECK_ASSIGN(o, d0_bignum_sub(o, G, one));
140 CHECK(d0_bignum_shl(o, o, -1)); // order o = (G-1)/2
146 d0_bignum_t *d0_dl_get_from_order(d0_bignum_t *G, const d0_bignum_t *o)
148 CHECK_ASSIGN(G, d0_bignum_shl(G, o, 1));
149 CHECK(d0_bignum_add(G, G, one));
155 D0_BOOL d0_dl_generate_key(size_t size, d0_bignum_t *G)
162 CHECK(d0_bignum_rand_bit_exact(temp0, size-1));
163 if(d0_bignum_isprime(temp0, 0) == 0)
165 CHECK(d0_dl_get_from_order(G, temp0));
166 if(d0_bignum_isprime(G, 10) == 0)
168 if(d0_bignum_isprime(temp0, 10) == 0) // finish the previous test
177 D0_BOOL d0_rsa_generate_key(size_t size, const d0_bignum_t *challenge, d0_bignum_t *d, d0_bignum_t *n)
179 // uses temp0 to temp4
182 int pb = (size + 1)/2;
190 CHECK(d0_bignum_rand_bit_exact(temp0, pb));
191 if(d0_bignum_isprime(temp0, 10) == 0)
193 CHECK(d0_bignum_sub(temp2, temp0, one));
194 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, challenge));
195 if(!d0_bignum_cmp(temp4, one))
204 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
205 if(!d0_bignum_cmp(temp1, temp0))
211 if(d0_bignum_isprime(temp1, 10) == 0)
213 CHECK(d0_bignum_sub(temp3, temp1, one));
214 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, challenge));
215 if(!d0_bignum_cmp(temp4, one))
223 CHECK(d0_bignum_mul(n, temp0, temp1));
225 // d = challenge^-1 mod (temp0-1)(temp1-1)
226 CHECK(d0_bignum_mul(temp0, temp2, temp3));
227 CHECK(d0_bignum_mod_inv(d, challenge, temp0));
233 D0_BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass)
235 // uses temp0 to temp4
238 int pb = (size + 1)/2;
246 CHECK(d0_bignum_rand_bit_exact(temp0, pb));
247 if(d0_bignum_isprime(temp0, 10) == 0)
249 CHECK(d0_bignum_sub(temp2, temp0, one));
250 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
251 if(!d0_bignum_cmp(temp4, one))
260 CHECK(d0_bignum_rand_bit_exact(temp1, qb));
261 if(!d0_bignum_cmp(temp1, temp0))
269 CHECK(d0_bignum_mul(ctx->rsa_n, temp0, temp1));
270 if(reject(ctx, pass))
273 if(d0_bignum_isprime(temp1, 10) == 0)
275 CHECK(d0_bignum_sub(temp3, temp1, one));
276 CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
277 if(!d0_bignum_cmp(temp4, one))
284 // ctx->rsa_d = ctx->rsa_e^-1 mod (temp0-1)(temp1-1)
285 CHECK(d0_bignum_mul(temp0, temp2, temp3));
286 CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
292 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_destructive(unsigned char *convbuf, size_t sz, unsigned char *outbuf, size_t outbuflen)
297 while(n > SHA_DIGESTSIZE)
299 memcpy(outbuf, sha(convbuf, sz), SHA_DIGESTSIZE);
300 outbuf += SHA_DIGESTSIZE;
302 for(i = 0; i < sz; ++i)
304 break; // stop until no carry
306 memcpy(outbuf, sha(convbuf, sz), n);
310 D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_bignum(const d0_bignum_t *in, unsigned char *outbuf, size_t outbuflen)
312 static unsigned char convbuf[1024];
315 CHECK(d0_bignum_export_unsigned(in, convbuf, sizeof(convbuf)) >= 0);
316 sz = (d0_bignum_size(in) + 7) / 8;
317 CHECK(d0_longhash_destructive(convbuf, sz, outbuf, outbuflen));
324 void d0_blind_id_clear(d0_blind_id_t *ctx)
326 if(ctx->rsa_n) d0_bignum_free(ctx->rsa_n);
327 if(ctx->rsa_e) d0_bignum_free(ctx->rsa_e);
328 if(ctx->rsa_d) d0_bignum_free(ctx->rsa_d);
329 if(ctx->schnorr_G) d0_bignum_free(ctx->schnorr_G);
330 if(ctx->schnorr_s) d0_bignum_free(ctx->schnorr_s);
331 if(ctx->schnorr_g_to_s) d0_bignum_free(ctx->schnorr_g_to_s);
332 if(ctx->schnorr_H_g_to_s_signature) d0_bignum_free(ctx->schnorr_H_g_to_s_signature);
333 if(ctx->rsa_blind_signature_camouflage) d0_bignum_free(ctx->rsa_blind_signature_camouflage);
334 if(ctx->r) d0_bignum_free(ctx->r);
335 if(ctx->challenge) d0_bignum_free(ctx->challenge);
336 if(ctx->t) d0_bignum_free(ctx->t);
337 if(ctx->g_to_t) d0_bignum_free(ctx->g_to_t);
338 if(ctx->other_g_to_t) d0_bignum_free(ctx->other_g_to_t);
339 memset(ctx, 0, sizeof(*ctx));
342 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
344 d0_blind_id_clear(ctx);
345 if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n));
346 if(src->rsa_e) CHECK_ASSIGN(ctx->rsa_e, d0_bignum_mov(NULL, src->rsa_e));
347 if(src->rsa_d) CHECK_ASSIGN(ctx->rsa_d, d0_bignum_mov(NULL, src->rsa_d));
348 if(src->schnorr_G) CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_mov(NULL, src->schnorr_G));
349 if(src->schnorr_s) CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_mov(NULL, src->schnorr_s));
350 if(src->schnorr_g_to_s) CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mov(NULL, src->schnorr_g_to_s));
351 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));
352 if(src->rsa_blind_signature_camouflage) CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_mov(NULL, src->rsa_blind_signature_camouflage));
353 if(src->r) CHECK_ASSIGN(ctx->r, d0_bignum_mov(NULL, src->r));
354 if(src->challenge) CHECK_ASSIGN(ctx->challenge, d0_bignum_mov(NULL, src->challenge));
355 if(src->t) CHECK_ASSIGN(ctx->t, d0_bignum_mov(NULL, src->t));
356 if(src->g_to_t) CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mov(NULL, src->g_to_t));
357 if(src->other_g_to_t) CHECK_ASSIGN(ctx->other_g_to_t, d0_bignum_mov(NULL, src->other_g_to_t));
358 memcpy(ctx->msg, src->msg, sizeof(ctx->msg));
359 ctx->msglen = src->msglen;
360 memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash));
363 d0_blind_id_clear(ctx);
367 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)
369 REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
371 CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
372 CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
373 CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
375 CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
377 CHECK(d0_rsa_generate_key(k+1, ctx->rsa_e, ctx->rsa_d, ctx->rsa_n)); // must fit G for sure
383 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
385 return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL);
388 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
390 d0_iobuf_t *in = NULL;
392 REPLACING(rsa_n); REPLACING(rsa_e); REPLACING(rsa_d);
394 in = d0_iobuf_open_read(inbuf, inbuflen);
396 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
397 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
398 CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, ctx->rsa_d));
399 return d0_iobuf_close(in, NULL);
402 d0_iobuf_close(in, NULL);
406 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
408 d0_iobuf_t *in = NULL;
410 REPLACING(rsa_n); REPLACING(rsa_e);
412 in = d0_iobuf_open_read(inbuf, inbuflen);
413 CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
414 CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
415 return d0_iobuf_close(in, NULL);
418 d0_iobuf_close(in, NULL);
422 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
424 d0_iobuf_t *out = NULL;
426 USING(rsa_n); USING(rsa_e); USING(rsa_d);
428 out = d0_iobuf_open_write(outbuf, *outbuflen);
429 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
430 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
431 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_d));
432 return d0_iobuf_close(out, outbuflen);
435 d0_iobuf_close(out, outbuflen);
439 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
441 d0_iobuf_t *out = NULL;
443 USING(rsa_n); USING(rsa_e);
445 out = d0_iobuf_open_write(outbuf, *outbuflen);
446 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
447 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
448 return d0_iobuf_close(out, outbuflen);
451 if(!d0_iobuf_close(out, outbuflen))
456 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
458 d0_iobuf_t *out = NULL;
459 static unsigned char convbuf[2048];
460 d0_iobuf_t *conv = NULL;
463 USING(rsa_n); USING(rsa_e);
465 out = d0_iobuf_open_write(outbuf, *outbuflen);
466 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
468 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
469 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
470 CHECK(d0_iobuf_close(conv, &sz));
473 n = (*outbuflen / 4) * 3;
474 if(n > SHA_DIGESTSIZE)
476 CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), n) == n);
477 CHECK(d0_iobuf_conv_base64_out(out));
479 return d0_iobuf_close(out, outbuflen);
483 d0_iobuf_close(conv, &sz);
484 d0_iobuf_close(out, outbuflen);
488 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx)
491 REPLACING(schnorr_G);
493 CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_zero(ctx->schnorr_G));
494 CHECK(d0_dl_generate_key(d0_bignum_size(ctx->rsa_n)-1, ctx->schnorr_G));
500 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
502 d0_iobuf_t *in = NULL;
504 REPLACING(schnorr_G);
506 in = d0_iobuf_open_read(inbuf, inbuflen);
507 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
508 return d0_iobuf_close(in, NULL);
511 d0_iobuf_close(in, NULL);
515 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
517 d0_iobuf_t *out = NULL;
521 out = d0_iobuf_open_write(outbuf, *outbuflen);
522 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
523 return d0_iobuf_close(out, outbuflen);
526 d0_iobuf_close(out, outbuflen);
530 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx)
532 // temps: temp0 = order
534 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s);
536 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
537 CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_rand_range(ctx->schnorr_s, zero, temp0));
538 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mod_pow(ctx->schnorr_g_to_s, four, ctx->schnorr_s, ctx->schnorr_G));
539 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
546 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
548 d0_iobuf_t *out = NULL;
549 static unsigned char shabuf[2048];
552 // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge
553 USING(rsa_n); USING(rsa_e); USING(schnorr_g_to_s);
554 REPLACING(rsa_blind_signature_camouflage);
556 out = d0_iobuf_open_write(outbuf, *outbuflen);
558 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_rand_bit_atmost(ctx->rsa_blind_signature_camouflage, d0_bignum_size(ctx->rsa_n)));
559 CHECK(d0_bignum_mod_pow(temp0, ctx->rsa_blind_signature_camouflage, ctx->rsa_e, ctx->rsa_n));
561 // we will actually sign HA(4^s) to prevent a malleability attack!
562 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
563 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
564 if(sz > sizeof(shabuf))
566 CHECK(d0_longhash_bignum(temp2, shabuf, sz));
567 CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz));
570 CHECK(d0_bignum_mod_mul(temp1, temp2, temp0, ctx->rsa_n));
571 CHECK(d0_iobuf_write_bignum(out, temp1));
572 return d0_iobuf_close(out, outbuflen);
575 d0_iobuf_close(out, outbuflen);
579 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)
581 d0_iobuf_t *in = NULL;
582 d0_iobuf_t *out = NULL;
584 // temps: temp0 input, temp1 temp0^d
585 USING(rsa_d); USING(rsa_n);
587 in = d0_iobuf_open_read(inbuf, inbuflen);
588 out = d0_iobuf_open_write(outbuf, *outbuflen);
590 CHECK(d0_iobuf_read_bignum(in, temp0));
591 CHECK(d0_bignum_mod_pow(temp1, temp0, ctx->rsa_d, ctx->rsa_n));
592 CHECK(d0_iobuf_write_bignum(out, temp1));
594 d0_iobuf_close(in, NULL);
595 return d0_iobuf_close(out, outbuflen);
598 d0_iobuf_close(in, NULL);
599 d0_iobuf_close(out, outbuflen);
603 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
605 d0_iobuf_t *in = NULL;
607 // temps: temp0 input, temp1 rsa_blind_signature_camouflage^-1
608 USING(rsa_blind_signature_camouflage); USING(rsa_n);
609 REPLACING(schnorr_H_g_to_s_signature);
611 in = d0_iobuf_open_read(inbuf, inbuflen);
613 CHECK(d0_iobuf_read_bignum(in, temp0));
614 CHECK(d0_bignum_mod_inv(temp1, ctx->rsa_blind_signature_camouflage, ctx->rsa_n));
615 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));
617 return d0_iobuf_close(in, NULL);
620 d0_iobuf_close(in, NULL);
624 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)
626 d0_iobuf_t *in = NULL;
628 REPLACING(rsa_blind_signature_camouflage);
630 in = d0_iobuf_open_read(inbuf, inbuflen);
632 CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_iobuf_read_bignum(in, ctx->rsa_blind_signature_camouflage));
634 return d0_iobuf_close(in, NULL);
637 d0_iobuf_close(in, NULL);
641 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)
643 d0_iobuf_t *out = NULL;
645 USING(rsa_blind_signature_camouflage);
647 out = d0_iobuf_open_write(outbuf, *outbuflen);
649 CHECK(d0_iobuf_write_bignum(out, ctx->rsa_blind_signature_camouflage));
651 return d0_iobuf_close(out, outbuflen);
654 d0_iobuf_close(out, outbuflen);
658 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
660 d0_iobuf_t *in = NULL;
662 REPLACING(schnorr_s); REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
664 in = d0_iobuf_open_read(inbuf, inbuflen);
666 CHECK_ASSIGN(ctx->schnorr_s, d0_iobuf_read_bignum(in, ctx->schnorr_s));
667 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
668 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
670 return d0_iobuf_close(in, NULL);
673 d0_iobuf_close(in, NULL);
677 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
679 d0_iobuf_t *in = NULL;
681 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
683 in = d0_iobuf_open_read(inbuf, inbuflen);
685 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
686 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
688 return d0_iobuf_close(in, NULL);
691 d0_iobuf_close(in, NULL);
695 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
697 d0_iobuf_t *out = NULL;
699 USING(schnorr_s); USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
701 out = d0_iobuf_open_write(outbuf, *outbuflen);
703 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_s));
704 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
705 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
707 return d0_iobuf_close(out, outbuflen);
710 d0_iobuf_close(out, outbuflen);
714 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
716 d0_iobuf_t *out = NULL;
718 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
720 out = d0_iobuf_open_write(outbuf, *outbuflen);
722 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
723 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
725 return d0_iobuf_close(out, outbuflen);
728 d0_iobuf_close(out, outbuflen);
732 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)
734 // first run: send 4^s, 4^s signature
735 // 1. get random r, send HASH(4^r)
737 d0_iobuf_t *out = NULL;
738 static unsigned char convbuf[1024];
739 d0_iobuf_t *conv = NULL;
743 // temps: temp0 order, temp0 4^r
746 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
749 REPLACING(r); REPLACING(t); REPLACING(g_to_t);
751 out = d0_iobuf_open_write(outbuf, *outbuflen);
757 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
758 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
759 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
762 // start schnorr ID scheme
763 // generate random number r; x = g^r; send hash of x, remember r, forget x
764 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
765 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
766 //CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G));
768 // initialize Signed Diffie Hellmann
769 // we already have the group order in temp1
770 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
771 // can we SOMEHOW do this with just one mod_pow?
773 CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G));
774 CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G));
777 // hash it, hash it, everybody hash it
778 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
779 CHECK(d0_iobuf_write_bignum(conv, temp0));
780 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
781 CHECK(d0_iobuf_write_packet(conv, msg, msglen));
782 CHECK(d0_iobuf_write_bignum(conv, temp0));
783 CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t));
784 d0_iobuf_close(conv, &sz);
786 CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), SCHNORR_HASHSIZE) == SCHNORR_HASHSIZE);
787 CHECK(d0_iobuf_write_packet(out, msg, msglen));
789 return d0_iobuf_close(out, outbuflen);
792 d0_iobuf_close(out, outbuflen);
796 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)
797 // first run: get 4^s, 4^s signature
800 // 3. send challenge challenge of SCHNORR_BITS
802 d0_iobuf_t *in = NULL;
803 d0_iobuf_t *out = NULL;
804 static unsigned char shabuf[2048];
807 // temps: temp0 order, temp0 signature check
810 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
812 REPLACING(schnorr_G);
818 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
821 USING(rsa_e); USING(rsa_n);
822 REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); REPLACING(t);
824 in = d0_iobuf_open_read(inbuf, inbuflen);
825 out = d0_iobuf_open_write(outbuf, *outbuflen);
831 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
832 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
833 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
835 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
836 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
837 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
838 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
839 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
840 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
842 // check signature of key (t = k^d, so, t^challenge = k)
843 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
845 // we will actually sign SHA(4^s) to prevent a malleability attack!
846 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
847 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
848 if(sz > sizeof(shabuf))
850 CHECK(d0_longhash_bignum(temp2, shabuf, sz));
851 CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz));
853 // + 7 / 8 is too large, so let's mod it
854 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
857 if(d0_bignum_cmp(temp0, temp1))
859 // accept the key anyway, but mark as failed signature! will later return 0 in status
860 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
864 CHECK(d0_iobuf_read_raw(in, ctx->msghash, SCHNORR_HASHSIZE));
865 ctx->msglen = MSGSIZE;
866 CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen));
869 CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS));
870 CHECK(d0_iobuf_write_bignum(out, ctx->challenge));
872 // Diffie Hellmann send
873 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
874 CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0));
875 CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G));
876 CHECK(d0_iobuf_write_bignum(out, temp0));
879 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
881 d0_iobuf_close(in, NULL);
882 return d0_iobuf_close(out, outbuflen);
885 d0_iobuf_close(in, NULL);
886 d0_iobuf_close(out, outbuflen);
890 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)
891 // 1. read challenge challenge of SCHNORR_BITS
892 // 2. reply with r + s * challenge mod order
894 d0_iobuf_t *in = NULL;
895 d0_iobuf_t *out = NULL;
897 // temps: 0 order, 1 prod, 2 y, 3 challenge
898 REPLACING(other_g_to_t); REPLACING(t);
899 USING(schnorr_G); USING(schnorr_s); USING(r); USING(g_to_t);
901 in = d0_iobuf_open_read(inbuf, inbuflen);
902 out = d0_iobuf_open_write(outbuf, *outbuflen);
904 CHECK(d0_iobuf_read_bignum(in, temp3));
905 CHECK(d0_bignum_cmp(temp3, zero) >= 0);
906 CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS);
908 // send response for schnorr ID scheme
909 // i.challenge. r + ctx->schnorr_s * temp3
910 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
911 CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_s, temp3, temp0));
912 CHECK(d0_bignum_mod_add(temp2, temp1, ctx->r, temp0));
913 CHECK(d0_iobuf_write_bignum(out, temp2));
915 // Diffie Hellmann recv
916 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
917 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
918 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
919 // Diffie Hellmann send
920 CHECK(d0_iobuf_write_bignum(out, ctx->g_to_t));
922 d0_iobuf_close(in, NULL);
923 return d0_iobuf_close(out, outbuflen);
926 d0_iobuf_close(in, NULL);
927 d0_iobuf_close(out, outbuflen);
931 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)
932 // 1. read y = r + s * challenge mod order
933 // 2. verify: g^y (g^s)^-challenge = g^(r+s*challenge-s*challenge) = g^r
934 // (check using H(g^r) which we know)
936 d0_iobuf_t *in = NULL;
937 static unsigned char convbuf[1024];
938 d0_iobuf_t *conv = NULL;
941 // temps: 0 y 1 order
942 USING(challenge); USING(schnorr_G);
943 REPLACING(other_g_to_t);
945 in = d0_iobuf_open_read(inbuf, inbuflen);
947 CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
948 CHECK(d0_iobuf_read_bignum(in, temp0));
949 CHECK(d0_bignum_cmp(temp0, zero) >= 0);
950 CHECK(d0_bignum_cmp(temp0, temp1) < 0);
952 // verify schnorr ID scheme
953 // we need 4^r = 4^temp0 (g^s)^-challenge
954 CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G));
955 CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G));
956 CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G));
957 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));
959 // Diffie Hellmann recv
960 CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t));
961 CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0);
962 CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0);
964 // hash it, hash it, everybody hash it
965 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
966 CHECK(d0_iobuf_write_bignum(conv, temp3));
967 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
968 CHECK(d0_iobuf_write_packet(conv, ctx->msg, ctx->msglen));
969 CHECK(d0_iobuf_write_bignum(conv, temp3));
970 CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t));
971 d0_iobuf_close(conv, &sz);
973 if(memcmp(sha(convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE))
975 // FAIL (not owned by player)
980 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
982 if(ctx->msglen <= *msglen)
983 memcpy(msg, ctx->msg, ctx->msglen);
985 memcpy(msg, ctx->msg, *msglen);
986 *msglen = ctx->msglen;
988 d0_iobuf_close(in, NULL);
992 d0_iobuf_close(in, NULL);
996 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx)
999 static unsigned char shabuf[2048];
1001 REPLACING(schnorr_H_g_to_s_signature);
1002 USING(schnorr_g_to_s); USING(rsa_d); USING(rsa_n);
1004 // we will actually sign SHA(4^s) to prevent a malleability attack!
1005 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
1006 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1007 if(sz > sizeof(shabuf))
1008 sz = sizeof(shabuf);
1009 CHECK(d0_longhash_bignum(temp2, shabuf, sz));
1010 CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz));
1012 // + 7 / 8 is too large, so let's mod it
1013 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1014 CHECK(d0_bignum_mod_pow(ctx->schnorr_H_g_to_s_signature, temp1, ctx->rsa_d, ctx->rsa_n));
1021 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)
1023 d0_iobuf_t *out = NULL;
1024 static unsigned char convbuf[1024];
1025 static unsigned char shabuf[1024];
1026 d0_iobuf_t *conv = NULL;
1031 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1037 out = d0_iobuf_open_write(outbuf, *outbuflen);
1043 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
1044 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s));
1045 CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature));
1048 // start schnorr SIGNATURE scheme
1049 // generate random number r; x = g^r; send hash of H(m||r), remember r, forget x
1050 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
1051 CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0));
1052 CHECK(d0_bignum_mod_pow(temp1, four, ctx->r, ctx->schnorr_G));
1054 // hash it, hash it, everybody hash it
1055 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1056 CHECK(d0_iobuf_write_packet(conv, message, msglen));
1057 CHECK(d0_iobuf_write_bignum(conv, temp1));
1058 d0_iobuf_close(conv, &sz);
1060 CHECK(d0_longhash_destructive(convbuf, sz, shabuf, (d0_bignum_size(temp0) + 7) / 8));
1061 CHECK(d0_bignum_import_unsigned(temp2, shabuf, (d0_bignum_size(temp0) + 7) / 8));
1062 CHECK(d0_iobuf_write_bignum(out, temp2));
1064 // multiply with secret, sub k, modulo order
1065 CHECK(d0_bignum_mod_mul(temp1, temp2, ctx->schnorr_s, temp0));
1066 CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0));
1067 CHECK(d0_iobuf_write_bignum(out, temp2));
1069 // write the message itself
1070 CHECK(d0_iobuf_write_packet(out, message, msglen));
1072 return d0_iobuf_close(out, outbuflen);
1075 d0_iobuf_close(out, outbuflen);
1079 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)
1081 d0_iobuf_t *in = NULL;
1082 d0_iobuf_t *conv = NULL;
1083 static unsigned char convbuf[2048];
1084 static unsigned char shabuf[2048];
1089 REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
1091 REPLACING(schnorr_G);
1097 USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
1100 USING(rsa_e); USING(rsa_n);
1102 in = d0_iobuf_open_read(inbuf, inbuflen);
1108 CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
1109 CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0);
1110 CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0);
1112 CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s));
1113 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0);
1114 CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0);
1115 CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature));
1116 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0);
1117 CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0);
1119 // check signature of key (t = k^d, so, t^challenge = k)
1120 CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n));
1122 // we will actually sign SHA(4^s) to prevent a malleability attack!
1123 CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s));
1124 sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting"
1125 if(sz > sizeof(shabuf))
1126 sz = sizeof(shabuf);
1127 CHECK(d0_longhash_bignum(temp2, shabuf, sz));
1128 CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz));
1130 // + 7 / 8 is too large, so let's mod it
1131 CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n));
1134 if(d0_bignum_cmp(temp0, temp1))
1136 // accept the key anyway, but mark as failed signature! will later return 0 in status
1137 CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature));
1141 CHECK(d0_dl_get_order(temp4, ctx->schnorr_G));
1142 CHECK(d0_iobuf_read_bignum(in, temp0)); // e == H(m || g^r)
1143 CHECK(d0_iobuf_read_bignum(in, temp1)); // x == (r - s*e) mod |G|
1144 CHECK(d0_iobuf_read_packet(in, msg, msglen));
1146 // VERIFY: g^x * (g^s)^-e = g^(x - s*e) = g^r
1148 // verify schnorr ID scheme
1149 // we need g^r = g^x (g^s)^e
1150 CHECK(d0_bignum_mod_pow(temp2, four, temp1, ctx->schnorr_G));
1151 CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G));
1152 CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); // temp3 now is g^r
1154 // hash it, hash it, everybody hash it
1155 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1156 CHECK(d0_iobuf_write_packet(conv, msg, *msglen));
1157 CHECK(d0_iobuf_write_bignum(conv, temp3));
1158 d0_iobuf_close(conv, &sz);
1160 CHECK(d0_longhash_destructive(convbuf, sz, shabuf, (d0_bignum_size(temp4) + 7) / 8));
1161 CHECK(d0_bignum_import_unsigned(temp1, shabuf, (d0_bignum_size(temp4) + 7) / 8));
1164 CHECK(!d0_bignum_cmp(temp0, temp1));
1167 *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
1169 d0_iobuf_close(in, NULL);
1173 d0_iobuf_close(in, NULL);
1177 D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1179 d0_iobuf_t *out = NULL;
1180 static unsigned char convbuf[1024];
1181 d0_iobuf_t *conv = NULL;
1186 USING(schnorr_g_to_s);
1188 out = d0_iobuf_open_write(outbuf, *outbuflen);
1189 conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
1191 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
1192 CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
1193 CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_g_to_s));
1194 CHECK(d0_iobuf_close(conv, &sz));
1197 n = (*outbuflen / 4) * 3;
1198 if(n > SHA_DIGESTSIZE)
1200 CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), n) == n);
1201 CHECK(d0_iobuf_conv_base64_out(out));
1203 return d0_iobuf_close(out, outbuflen);
1207 d0_iobuf_close(conv, &sz);
1208 d0_iobuf_close(out, outbuflen);
1212 D0_BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
1214 USING(t); USING(other_g_to_t); USING(schnorr_G);
1216 // temps: temp0 result
1217 CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G));
1218 return d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen);
1224 d0_blind_id_t *d0_blind_id_new(void)
1226 d0_blind_id_t *b = d0_malloc(sizeof(d0_blind_id_t));
1227 memset(b, 0, sizeof(*b));
1231 void d0_blind_id_free(d0_blind_id_t *a)
1233 d0_blind_id_clear(a);
1237 void d0_blind_id_util_sha256(char *out, const char *in, size_t n)
1240 SHA256_Init(&context);
1241 SHA256_Update(&context, (const unsigned char *) in, n);
1242 return SHA256_Final((unsigned char *) out, &context);