X-Git-Url: http://de.git.xonotic.org/?p=xonotic%2Fd0_blind_id.git;a=blobdiff_plain;f=d0_blind_id.c;h=3abfb9da74d1b24406fc06acea886fbb3f7ad8d7;hp=f46a8d1c3f34aef1fa733bc2ed8934f93e28e120;hb=09adb6717861941b70ce52996a6159ffe23c5d0c;hpb=1e6764b3137ab0e1ecbbe5fdf0108d3c91357489 diff --git a/d0_blind_id.c b/d0_blind_id.c index f46a8d1..3abfb9d 100644 --- a/d0_blind_id.c +++ b/d0_blind_id.c @@ -1,28 +1,53 @@ /* -Blind-ID library for user identification using RSA blind signatures -Copyright (C) 2010 Rudolf Polzer - -This library is free software; you can redistribute it and/or -modify it under the terms of the GNU Lesser General Public -License as published by the Free Software Foundation; either -version 2.1 of the License, or (at your option) any later version. - -This library is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -Lesser General Public License for more details. - -You should have received a copy of the GNU Lesser General Public -License along with this library; if not, write to the Free Software -Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA -*/ + * FILE: d0_blind_id.c + * AUTHOR: Rudolf Polzer - divVerent@xonotic.org + * + * Copyright (c) 2010, Rudolf Polzer + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the copyright holder nor the names of contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $Format:commit %H$ + * $Id$ + */ #include "d0_blind_id.h" #include #include #include "d0_bignum.h" -#include "sha1.h" +#include "sha2.h" + +// our SHA is SHA-256 +#define SHA_DIGESTSIZE 32 +const char *sha(const unsigned char *in, size_t len) +{ + static char h[32]; + d0_blind_id_util_sha256(h, (const char *) in, len); + return h; +} // for zero knowledge, we need multiple instances of schnorr ID scheme... should normally be sequential // parallel schnorr ID is not provably zero knowledge :( @@ -32,9 +57,10 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA #define SCHNORR_BITS 20 // probability of cheat: 2^(-bits+1) -#define SCHNORR_HASHSIZE 3 -// cannot be >= SHA_DIGEST_LENGTH +#define SCHNORR_HASHSIZE SHA_DIGESTSIZE +// cannot be >= SHA_DIGESTSIZE // *8 must be >= SCHNORR_BITS +// no need to save bits here #define MSGSIZE 640 // ought to be enough for anyone @@ -50,15 +76,17 @@ struct d0_blind_id_s d0_bignum_t *schnorr_s; // public data (player ID public key, this is what the server gets to know) - d0_bignum_t *schnorr_4_to_s; - d0_bignum_t *schnorr_H_4_to_s_signature; // 0 when signature is invalid + d0_bignum_t *schnorr_g_to_s; + d0_bignum_t *schnorr_H_g_to_s_signature; // 0 when signature is invalid // as hash function H, we get the SHA1 and reinterpret as bignum - yes, it always is < 160 bits // temp data d0_bignum_t *rsa_blind_signature_camouflage; // random number blind signature d0_bignum_t *r; // random number for schnorr ID - d0_bignum_t *other_4_to_r; // for DH key exchange + d0_bignum_t *t; // for DH key exchange + d0_bignum_t *g_to_t; // for DH key exchange + d0_bignum_t *other_g_to_t; // for DH key exchange d0_bignum_t *challenge; // challenge char msghash[SCHNORR_HASHSIZE]; // init hash @@ -68,15 +96,17 @@ struct d0_blind_id_s #define CHECK(x) do { if(!(x)) goto fail; } while(0) #define CHECK_ASSIGN(var, value) do { d0_bignum_t *val; val = value; if(!val) goto fail; var = val; } while(0) +#define MPCHECK(x) do { if(!failed) if(!(x)) failed = 1; } while(0) +#define MPCHECK_ASSIGN(var, value) do { if(!failed) { d0_bignum_t *val; val = value; if(val) var = val; else failed = 1; } } while(0) #define USING(x) if(!(ctx->x)) return 0 #define REPLACING(x) static d0_bignum_t *zero, *one, *four, *temp0, *temp1, *temp2, *temp3, *temp4; -void d0_blind_id_INITIALIZE(void) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_INITIALIZE(void) { - d0_bignum_INITIALIZE(); + CHECK(d0_bignum_INITIALIZE()); CHECK_ASSIGN(zero, d0_bignum_int(zero, 0)); CHECK_ASSIGN(one, d0_bignum_int(one, 1)); CHECK_ASSIGN(four, d0_bignum_int(four, 4)); @@ -85,8 +115,9 @@ void d0_blind_id_INITIALIZE(void) CHECK_ASSIGN(temp2, d0_bignum_int(temp2, 0)); CHECK_ASSIGN(temp3, d0_bignum_int(temp3, 0)); CHECK_ASSIGN(temp4, d0_bignum_int(temp4, 0)); + return 1; fail: - ; + return 0; } void d0_blind_id_SHUTDOWN(void) @@ -121,7 +152,7 @@ fail: return NULL; } -BOOL d0_dl_generate_key(size_t size, d0_bignum_t *G) +D0_BOOL d0_dl_generate_key(size_t size, d0_bignum_t *G) { // using: temp0 if(size < 16) @@ -143,7 +174,7 @@ fail: return 0; } -BOOL d0_rsa_generate_key(size_t size, const d0_bignum_t *challenge, d0_bignum_t *d, d0_bignum_t *n) +D0_BOOL d0_rsa_generate_key(size_t size, const d0_bignum_t *challenge, d0_bignum_t *d, d0_bignum_t *n) { // uses temp0 to temp4 int fail = 0; @@ -199,7 +230,7 @@ fail: return 0; } -BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass) +D0_BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass) { // uses temp0 to temp4 int fail = 0; @@ -258,36 +289,35 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_longhash_destructive(d0_bignum_t *clobberme, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_destructive(unsigned char *convbuf, size_t sz, unsigned char *outbuf, size_t outbuflen) { - d0_iobuf_t *out = NULL; - static unsigned char convbuf[1024]; - d0_iobuf_t *conv = NULL; - size_t n, sz; + size_t n, i; - n = *outbuflen; + n = outbuflen; while(n > SHA_DIGESTSIZE) { - conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); - CHECK(d0_iobuf_write_bignum(conv, temp0)); - CHECK(d0_iobuf_close(conv, &sz)); - conv = NULL; memcpy(outbuf, sha(convbuf, sz), SHA_DIGESTSIZE); outbuf += SHA_DIGESTSIZE; n -= SHA_DIGESTSIZE; - CHECK(d0_bignum_add(temp0, temp0, one)); + for(i = 0; i < sz; ++i) + if(++convbuf[i]) + break; // stop until no carry } - conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); - CHECK(d0_iobuf_write_bignum(conv, temp0)); - CHECK(d0_iobuf_close(conv, &sz)); - conv = NULL; memcpy(outbuf, sha(convbuf, sz), n); + return 1; +} - return d0_iobuf_close(out, outbuflen); +D0_WARN_UNUSED_RESULT D0_BOOL d0_longhash_bignum(const d0_bignum_t *in, unsigned char *outbuf, size_t outbuflen) +{ + static unsigned char convbuf[1024]; + size_t sz; + + CHECK(d0_bignum_export_unsigned(in, convbuf, sizeof(convbuf)) >= 0); + sz = (d0_bignum_size(in) + 7) / 8; + CHECK(d0_longhash_destructive(convbuf, sz, outbuf, outbuflen)); + return 1; fail: - if(conv) - d0_iobuf_close(conv, &sz); return 0; } @@ -298,16 +328,18 @@ void d0_blind_id_clear(d0_blind_id_t *ctx) if(ctx->rsa_d) d0_bignum_free(ctx->rsa_d); if(ctx->schnorr_G) d0_bignum_free(ctx->schnorr_G); if(ctx->schnorr_s) d0_bignum_free(ctx->schnorr_s); - if(ctx->schnorr_4_to_s) d0_bignum_free(ctx->schnorr_4_to_s); - if(ctx->schnorr_H_4_to_s_signature) d0_bignum_free(ctx->schnorr_H_4_to_s_signature); + if(ctx->schnorr_g_to_s) d0_bignum_free(ctx->schnorr_g_to_s); + if(ctx->schnorr_H_g_to_s_signature) d0_bignum_free(ctx->schnorr_H_g_to_s_signature); if(ctx->rsa_blind_signature_camouflage) d0_bignum_free(ctx->rsa_blind_signature_camouflage); if(ctx->r) d0_bignum_free(ctx->r); if(ctx->challenge) d0_bignum_free(ctx->challenge); - if(ctx->other_4_to_r) d0_bignum_free(ctx->other_4_to_r); + if(ctx->t) d0_bignum_free(ctx->t); + if(ctx->g_to_t) d0_bignum_free(ctx->g_to_t); + if(ctx->other_g_to_t) d0_bignum_free(ctx->other_g_to_t); memset(ctx, 0, sizeof(*ctx)); } -WARN_UNUSED_RESULT BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src) { d0_blind_id_clear(ctx); if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n)); @@ -315,12 +347,14 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t if(src->rsa_d) CHECK_ASSIGN(ctx->rsa_d, d0_bignum_mov(NULL, src->rsa_d)); if(src->schnorr_G) CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_mov(NULL, src->schnorr_G)); if(src->schnorr_s) CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_mov(NULL, src->schnorr_s)); - if(src->schnorr_4_to_s) CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_bignum_mov(NULL, src->schnorr_4_to_s)); - if(src->schnorr_H_4_to_s_signature) CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_bignum_mov(NULL, src->schnorr_H_4_to_s_signature)); + if(src->schnorr_g_to_s) CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mov(NULL, src->schnorr_g_to_s)); + 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)); if(src->rsa_blind_signature_camouflage) CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_mov(NULL, src->rsa_blind_signature_camouflage)); if(src->r) CHECK_ASSIGN(ctx->r, d0_bignum_mov(NULL, src->r)); if(src->challenge) CHECK_ASSIGN(ctx->challenge, d0_bignum_mov(NULL, src->challenge)); - if(src->other_4_to_r) CHECK_ASSIGN(ctx->other_4_to_r, d0_bignum_mov(NULL, src->other_4_to_r)); + if(src->t) CHECK_ASSIGN(ctx->t, d0_bignum_mov(NULL, src->t)); + if(src->g_to_t) CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mov(NULL, src->g_to_t)); + if(src->other_g_to_t) CHECK_ASSIGN(ctx->other_g_to_t, d0_bignum_mov(NULL, src->other_g_to_t)); memcpy(ctx->msg, src->msg, sizeof(ctx->msg)); ctx->msglen = src->msglen; memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash)); @@ -330,7 +364,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key_fastreject(d0_blind_id_t *ctx, int k, d0_fastreject_function reject, void *pass) +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) { REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n); @@ -346,12 +380,12 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k) { return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL); } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; @@ -369,7 +403,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; @@ -385,7 +419,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; @@ -402,7 +436,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; @@ -419,7 +453,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; static unsigned char convbuf[2048]; @@ -451,7 +485,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx) { USING(rsa_n); REPLACING(schnorr_G); @@ -463,7 +497,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id_modulus(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; @@ -478,7 +512,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id_modulus(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; @@ -493,41 +527,45 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx) { // temps: temp0 = order USING(schnorr_G); - REPLACING(schnorr_s); REPLACING(schnorr_4_to_s); + REPLACING(schnorr_s); REPLACING(schnorr_g_to_s); CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); - CHECK(d0_bignum_shl(temp1, ctx->schnorr_G, -1)); CHECK_ASSIGN(ctx->schnorr_s, d0_bignum_rand_range(ctx->schnorr_s, zero, temp0)); - CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_bignum_mod_pow(ctx->schnorr_4_to_s, four, ctx->schnorr_s, ctx->schnorr_G)); - CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_bignum_zero(ctx->schnorr_H_4_to_s_signature)); + CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_bignum_mod_pow(ctx->schnorr_g_to_s, four, ctx->schnorr_s, ctx->schnorr_G)); + CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_bignum_zero(ctx->schnorr_H_g_to_s_signature)); return 1; fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; - static unsigned char convbuf[2048]; + static unsigned char shabuf[2048]; size_t sz; // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge - USING(rsa_n); USING(rsa_e); USING(schnorr_4_to_s); + USING(rsa_n); USING(rsa_e); USING(schnorr_g_to_s); REPLACING(rsa_blind_signature_camouflage); out = d0_iobuf_open_write(outbuf, *outbuflen); CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_bignum_rand_bit_atmost(ctx->rsa_blind_signature_camouflage, d0_bignum_size(ctx->rsa_n))); CHECK(d0_bignum_mod_pow(temp0, ctx->rsa_blind_signature_camouflage, ctx->rsa_e, ctx->rsa_n)); - // we will actually sign SHA(4^s) to prevent a malleability attack! - sz = (d0_bignum_size(ctx->schnorr_4_to_s) + 7) / 8; - CHECK(d0_bignum_export_unsigned(ctx->schnorr_4_to_s, convbuf, sz) >= 0); - CHECK(d0_bignum_import_unsigned(temp2, sha(convbuf, sz), SHA_DIGESTSIZE)); + + // we will actually sign HA(4^s) to prevent a malleability attack! + CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s)); + sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting" + if(sz > sizeof(shabuf)) + sz = sizeof(shabuf); + CHECK(d0_longhash_bignum(temp2, shabuf, sz)); + CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); + // hash complete CHECK(d0_bignum_mod_mul(temp1, temp2, temp0, ctx->rsa_n)); CHECK(d0_iobuf_write_bignum(out, temp1)); @@ -538,7 +576,7 @@ fail: return 0; } -WARN_UNUSED_RESULT 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) +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) { d0_iobuf_t *in = NULL; d0_iobuf_t *out = NULL; @@ -562,19 +600,19 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; // temps: temp0 input, temp1 rsa_blind_signature_camouflage^-1 USING(rsa_blind_signature_camouflage); USING(rsa_n); - REPLACING(schnorr_H_4_to_s_signature); + REPLACING(schnorr_H_g_to_s_signature); in = d0_iobuf_open_read(inbuf, inbuflen); CHECK(d0_iobuf_read_bignum(in, temp0)); CHECK(d0_bignum_mod_inv(temp1, ctx->rsa_blind_signature_camouflage, ctx->rsa_n)); - CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_bignum_mod_mul(ctx->schnorr_H_4_to_s_signature, temp0, temp1, ctx->rsa_n)); + 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)); return d0_iobuf_close(in, NULL); @@ -583,7 +621,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_id_request_camouflage(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +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) { d0_iobuf_t *in = NULL; @@ -600,7 +638,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_id_request_camouflage(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +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) { d0_iobuf_t *out = NULL; @@ -617,17 +655,17 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; - REPLACING(schnorr_s); REPLACING(schnorr_4_to_s); REPLACING(schnorr_H_4_to_s_signature); + REPLACING(schnorr_s); REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature); in = d0_iobuf_open_read(inbuf, inbuflen); CHECK_ASSIGN(ctx->schnorr_s, d0_iobuf_read_bignum(in, ctx->schnorr_s)); - CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_4_to_s)); - CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_4_to_s_signature)); + CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s)); + CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature)); return d0_iobuf_close(in, NULL); @@ -636,16 +674,16 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen) { d0_iobuf_t *in = NULL; - REPLACING(schnorr_4_to_s); REPLACING(schnorr_H_4_to_s_signature); + REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature); in = d0_iobuf_open_read(inbuf, inbuflen); - CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_4_to_s)); - CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_4_to_s_signature)); + CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s)); + CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature)); return d0_iobuf_close(in, NULL); @@ -654,17 +692,17 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; - USING(schnorr_s); USING(schnorr_4_to_s); USING(schnorr_H_4_to_s_signature); + USING(schnorr_s); USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); out = d0_iobuf_open_write(outbuf, *outbuflen); CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_s)); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_4_to_s)); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_4_to_s_signature)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature)); return d0_iobuf_close(out, outbuflen); @@ -673,16 +711,16 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; - USING(schnorr_4_to_s); USING(schnorr_H_4_to_s_signature); + USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); out = d0_iobuf_open_write(outbuf, *outbuflen); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_4_to_s)); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_4_to_s_signature)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature)); return d0_iobuf_close(out, outbuflen); @@ -691,7 +729,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_id_t *ctx, BOOL is_first, BOOL send_modulus, char *msg, size_t msglen, char *outbuf, size_t *outbuflen) +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) // start = // first run: send 4^s, 4^s signature // 1. get random r, send HASH(4^r) @@ -700,14 +738,15 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_ static unsigned char convbuf[1024]; d0_iobuf_t *conv = NULL; size_t sz = 0; + D0_BOOL failed = 0; // temps: temp0 order, temp0 4^r if(is_first) { - USING(schnorr_4_to_s); USING(schnorr_H_4_to_s_signature); + USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); } USING(schnorr_G); - REPLACING(r); + REPLACING(r); REPLACING(t); REPLACING(g_to_t); out = d0_iobuf_open_write(outbuf, *outbuflen); @@ -716,21 +755,32 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_ // send ID if(send_modulus) CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G)); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_4_to_s)); - CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_4_to_s_signature)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature)); } // start schnorr ID scheme // generate random number r; x = g^r; send hash of x, remember r, forget x CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0)); + //CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G)); + + // initialize Signed Diffie Hellmann + // we already have the group order in temp1 + CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0)); + // can we SOMEHOW do this with just one mod_pow? + CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G)); + CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G)); + CHECK(!failed); // hash it, hash it, everybody hash it conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); CHECK(d0_iobuf_write_bignum(conv, temp0)); + CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t)); CHECK(d0_iobuf_write_packet(conv, msg, msglen)); CHECK(d0_iobuf_write_bignum(conv, temp0)); + CHECK(d0_iobuf_write_bignum(conv, ctx->g_to_t)); d0_iobuf_close(conv, &sz); conv = NULL; CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), SCHNORR_HASHSIZE) == SCHNORR_HASHSIZE); @@ -743,7 +793,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_blind_id_t *ctx, BOOL is_first, BOOL recv_modulus, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen, BOOL *status) +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) // first run: get 4^s, 4^s signature // 1. check sig // 2. save HASH(4^r) @@ -751,13 +801,13 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl { d0_iobuf_t *in = NULL; d0_iobuf_t *out = NULL; - static unsigned char convbuf[2048]; + static unsigned char shabuf[2048]; size_t sz; // temps: temp0 order, temp0 signature check if(is_first) { - REPLACING(schnorr_4_to_s); REPLACING(schnorr_H_4_to_s_signature); + REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature); if(recv_modulus) REPLACING(schnorr_G); else @@ -765,11 +815,11 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl } else { - USING(schnorr_4_to_s); USING(schnorr_H_4_to_s_signature); + USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); USING(schnorr_G); } USING(rsa_e); USING(rsa_n); - REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); + REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); REPLACING(t); in = d0_iobuf_open_read(inbuf, inbuflen); out = d0_iobuf_open_write(outbuf, *outbuflen); @@ -782,25 +832,32 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0); CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0); } - CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_4_to_s)); - CHECK(d0_bignum_cmp(ctx->schnorr_4_to_s, zero) >= 0); - CHECK(d0_bignum_cmp(ctx->schnorr_4_to_s, ctx->schnorr_G) < 0); - CHECK_ASSIGN(ctx->schnorr_H_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_4_to_s_signature)); - CHECK(d0_bignum_cmp(ctx->schnorr_H_4_to_s_signature, zero) >= 0); - CHECK(d0_bignum_cmp(ctx->schnorr_H_4_to_s_signature, ctx->rsa_n) < 0); + CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s)); + CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0); + CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0); + CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature)); + CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0); + CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0); // check signature of key (t = k^d, so, t^challenge = k) - CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_4_to_s_signature, ctx->rsa_e, ctx->rsa_n)); + CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n)); + // we will actually sign SHA(4^s) to prevent a malleability attack! - sz = (d0_bignum_size(ctx->schnorr_4_to_s) + 7) / 8; - CHECK(d0_bignum_export_unsigned(ctx->schnorr_4_to_s, convbuf, sz) >= 0); - CHECK(d0_bignum_import_unsigned(temp2, sha(convbuf, sz), SHA_DIGESTSIZE)); + CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s)); + sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting" + if(sz > sizeof(shabuf)) + sz = sizeof(shabuf); + CHECK(d0_longhash_bignum(temp2, shabuf, sz)); + CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); + + // + 7 / 8 is too large, so let's mod it CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n)); + // hash complete if(d0_bignum_cmp(temp0, temp1)) { // accept the key anyway, but mark as failed signature! will later return 0 in status - CHECK(d0_bignum_zero(ctx->schnorr_H_4_to_s_signature)); + CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature)); } } @@ -810,17 +867,16 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl // send challenge CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS)); - CHECK(d0_iobuf_write_bignum(out, ctx->challenge)); - // Diffie Hellmann + // Diffie Hellmann send CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); - CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0)); - CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G)); + CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0)); + CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G)); CHECK(d0_iobuf_write_bignum(out, temp0)); if(status) - *status = !!d0_bignum_cmp(ctx->schnorr_H_4_to_s_signature, zero); + *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero); d0_iobuf_close(in, NULL); return d0_iobuf_close(out, outbuflen); @@ -831,7 +887,7 @@ fail: return 0; } -WARN_UNUSED_RESULT 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) +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) // 1. read challenge challenge of SCHNORR_BITS // 2. reply with r + s * challenge mod order { @@ -839,8 +895,8 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_response(d0_bli d0_iobuf_t *out = NULL; // temps: 0 order, 1 prod, 2 y, 3 challenge - REPLACING(other_4_to_r); - USING(schnorr_G); USING(schnorr_s); USING(r); + REPLACING(other_g_to_t); REPLACING(t); + USING(schnorr_G); USING(schnorr_s); USING(r); USING(g_to_t); in = d0_iobuf_open_read(inbuf, inbuflen); out = d0_iobuf_open_write(outbuf, *outbuflen); @@ -849,11 +905,6 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_response(d0_bli CHECK(d0_bignum_cmp(temp3, zero) >= 0); CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS); - // Diffie Hellmann - CHECK_ASSIGN(ctx->other_4_to_r, d0_iobuf_read_bignum(in, ctx->other_4_to_r)); - CHECK(d0_bignum_cmp(ctx->other_4_to_r, zero) > 0); - CHECK(d0_bignum_cmp(ctx->other_4_to_r, ctx->schnorr_G) < 0); - // send response for schnorr ID scheme // i.challenge. r + ctx->schnorr_s * temp3 CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); @@ -861,6 +912,13 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_response(d0_bli CHECK(d0_bignum_mod_add(temp2, temp1, ctx->r, temp0)); CHECK(d0_iobuf_write_bignum(out, temp2)); + // Diffie Hellmann recv + CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t)); + CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0); + CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0); + // Diffie Hellmann send + CHECK(d0_iobuf_write_bignum(out, ctx->g_to_t)); + d0_iobuf_close(in, NULL); return d0_iobuf_close(out, outbuflen); @@ -870,7 +928,7 @@ fail: return 0; } -WARN_UNUSED_RESULT 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, BOOL *status) +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) // 1. read y = r + s * challenge mod order // 2. verify: g^y (g^s)^-challenge = g^(r+s*challenge-s*challenge) = g^r // (check using H(g^r) which we know) @@ -882,7 +940,7 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_verify(d0_blind // temps: 0 y 1 order USING(challenge); USING(schnorr_G); - REPLACING(other_4_to_r); + REPLACING(other_g_to_t); in = d0_iobuf_open_read(inbuf, inbuflen); @@ -892,18 +950,24 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_verify(d0_blind CHECK(d0_bignum_cmp(temp0, temp1) < 0); // verify schnorr ID scheme - // we need 4^temp0 (g^s)^-challenge - CHECK(d0_bignum_neg(temp1, ctx->challenge)); - CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_4_to_s, temp1, ctx->schnorr_G)); + // we need 4^r = 4^temp0 (g^s)^-challenge + CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G)); + CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G)); CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G)); - CHECK_ASSIGN(ctx->other_4_to_r, d0_bignum_mod_mul(ctx->other_4_to_r, temp1, temp2, ctx->schnorr_G)); - // hash must be equal to msghash + CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); + + // Diffie Hellmann recv + CHECK_ASSIGN(ctx->other_g_to_t, d0_iobuf_read_bignum(in, ctx->other_g_to_t)); + CHECK(d0_bignum_cmp(ctx->other_g_to_t, zero) > 0); + CHECK(d0_bignum_cmp(ctx->other_g_to_t, ctx->schnorr_G) < 0); // hash it, hash it, everybody hash it conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); - CHECK(d0_iobuf_write_bignum(conv, ctx->other_4_to_r)); + CHECK(d0_iobuf_write_bignum(conv, temp3)); + CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t)); CHECK(d0_iobuf_write_packet(conv, ctx->msg, ctx->msglen)); - CHECK(d0_iobuf_write_bignum(conv, ctx->other_4_to_r)); + CHECK(d0_iobuf_write_bignum(conv, temp3)); + CHECK(d0_iobuf_write_bignum(conv, ctx->other_g_to_t)); d0_iobuf_close(conv, &sz); conv = NULL; if(memcmp(sha(convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE)) @@ -913,7 +977,7 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_verify(d0_blind } if(status) - *status = !!d0_bignum_cmp(ctx->schnorr_H_4_to_s_signature, zero); + *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero); if(ctx->msglen <= *msglen) memcpy(msg, ctx->msg, ctx->msglen); @@ -929,19 +993,204 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx) +{ + size_t sz; + static unsigned char shabuf[2048]; + + REPLACING(schnorr_H_g_to_s_signature); + USING(schnorr_g_to_s); USING(rsa_d); USING(rsa_n); + + // we will actually sign SHA(4^s) to prevent a malleability attack! + CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s)); + sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting" + if(sz > sizeof(shabuf)) + sz = sizeof(shabuf); + CHECK(d0_longhash_bignum(temp2, shabuf, sz)); + CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); + + // + 7 / 8 is too large, so let's mod it + CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n)); + CHECK(d0_bignum_mod_pow(ctx->schnorr_H_g_to_s_signature, temp1, ctx->rsa_d, ctx->rsa_n)); + return 1; + +fail: + return 0; +} + +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) +{ + d0_iobuf_t *out = NULL; + static unsigned char convbuf[1024]; + static unsigned char shabuf[1024]; + d0_iobuf_t *conv = NULL; + size_t sz = 0; + + if(is_first) + { + USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); + } + USING(schnorr_G); + USING(schnorr_s); + REPLACING(r); + + out = d0_iobuf_open_write(outbuf, *outbuflen); + + if(is_first) + { + // send ID + if(send_modulus) + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_g_to_s)); + CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_H_g_to_s_signature)); + } + + // start schnorr SIGNATURE scheme + // generate random number r; x = g^r; send hash of H(m||r), remember r, forget x + CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); + CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0)); + CHECK(d0_bignum_mod_pow(temp1, four, ctx->r, ctx->schnorr_G)); + + // hash it, hash it, everybody hash it + conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); + CHECK(d0_iobuf_write_packet(conv, message, msglen)); + CHECK(d0_iobuf_write_bignum(conv, temp1)); + d0_iobuf_close(conv, &sz); + conv = NULL; + CHECK(d0_longhash_destructive(convbuf, sz, shabuf, (d0_bignum_size(temp0) + 7) / 8)); + CHECK(d0_bignum_import_unsigned(temp2, shabuf, (d0_bignum_size(temp0) + 7) / 8)); + CHECK(d0_iobuf_write_bignum(out, temp2)); + + // multiply with secret, sub k, modulo order + CHECK(d0_bignum_mod_mul(temp1, temp2, ctx->schnorr_s, temp0)); + CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0)); + CHECK(d0_iobuf_write_bignum(out, temp2)); + + // write the message itself + CHECK(d0_iobuf_write_packet(out, message, msglen)); + + return d0_iobuf_close(out, outbuflen); + +fail: + d0_iobuf_close(out, outbuflen); + return 0; +} + +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) +{ + d0_iobuf_t *in = NULL; + d0_iobuf_t *conv = NULL; + static unsigned char convbuf[2048]; + static unsigned char shabuf[2048]; + size_t sz; + + if(is_first) + { + REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature); + if(recv_modulus) + REPLACING(schnorr_G); + else + USING(schnorr_G); + } + else + { + USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature); + USING(schnorr_G); + } + USING(rsa_e); USING(rsa_n); + + in = d0_iobuf_open_read(inbuf, inbuflen); + + if(is_first) + { + if(recv_modulus) + { + CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G)); + CHECK(d0_bignum_cmp(ctx->schnorr_G, zero) > 0); + CHECK(d0_bignum_cmp(ctx->schnorr_G, ctx->rsa_n) < 0); + } + CHECK_ASSIGN(ctx->schnorr_g_to_s, d0_iobuf_read_bignum(in, ctx->schnorr_g_to_s)); + CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, zero) >= 0); + CHECK(d0_bignum_cmp(ctx->schnorr_g_to_s, ctx->schnorr_G) < 0); + CHECK_ASSIGN(ctx->schnorr_H_g_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_H_g_to_s_signature)); + CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero) >= 0); + CHECK(d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, ctx->rsa_n) < 0); + + // check signature of key (t = k^d, so, t^challenge = k) + CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_H_g_to_s_signature, ctx->rsa_e, ctx->rsa_n)); + + // we will actually sign SHA(4^s) to prevent a malleability attack! + CHECK(d0_bignum_mov(temp2, ctx->schnorr_g_to_s)); + sz = (d0_bignum_size(ctx->rsa_n) + 7) / 8; // this is too long, so we have to take the value % rsa_n when "decrypting" + if(sz > sizeof(shabuf)) + sz = sizeof(shabuf); + CHECK(d0_longhash_bignum(temp2, shabuf, sz)); + CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); + + // + 7 / 8 is too large, so let's mod it + CHECK(d0_bignum_divmod(NULL, temp1, temp2, ctx->rsa_n)); + + // hash complete + if(d0_bignum_cmp(temp0, temp1)) + { + // accept the key anyway, but mark as failed signature! will later return 0 in status + CHECK(d0_bignum_zero(ctx->schnorr_H_g_to_s_signature)); + } + } + + CHECK(d0_dl_get_order(temp4, ctx->schnorr_G)); + CHECK(d0_iobuf_read_bignum(in, temp0)); // e == H(m || g^r) + CHECK(d0_iobuf_read_bignum(in, temp1)); // x == (r - s*e) mod |G| + CHECK(d0_iobuf_read_packet(in, msg, msglen)); + + // VERIFY: g^x * (g^s)^-e = g^(x - s*e) = g^r + + // verify schnorr ID scheme + // we need g^r = g^x (g^s)^e + CHECK(d0_bignum_mod_pow(temp2, four, temp1, ctx->schnorr_G)); + CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G)); + CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); // temp3 now is g^r + + // hash it, hash it, everybody hash it + conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); + CHECK(d0_iobuf_write_packet(conv, msg, *msglen)); + CHECK(d0_iobuf_write_bignum(conv, temp3)); + d0_iobuf_close(conv, &sz); + conv = NULL; + CHECK(d0_longhash_destructive(convbuf, sz, shabuf, (d0_bignum_size(temp4) + 7) / 8)); + CHECK(d0_bignum_import_unsigned(temp1, shabuf, (d0_bignum_size(temp4) + 7) / 8)); + + // verify signature + CHECK(!d0_bignum_cmp(temp0, temp1)); + + if(status) + *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero); + + d0_iobuf_close(in, NULL); + return 1; + +fail: + d0_iobuf_close(in, NULL); + return 0; +} + +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { d0_iobuf_t *out = NULL; static unsigned char convbuf[1024]; d0_iobuf_t *conv = NULL; size_t sz, n; - USING(schnorr_4_to_s); + USING(rsa_n); + USING(rsa_e); + USING(schnorr_g_to_s); out = d0_iobuf_open_write(outbuf, *outbuflen); conv = d0_iobuf_open_write(convbuf, sizeof(convbuf)); - CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_4_to_s)); + CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n)); + CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e)); + CHECK(d0_iobuf_write_bignum(conv, ctx->schnorr_g_to_s)); CHECK(d0_iobuf_close(conv, &sz)); conv = NULL; @@ -960,13 +1209,13 @@ fail: return 0; } -BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) +D0_BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen) { - USING(r); USING(other_4_to_r); USING(schnorr_G); + USING(t); USING(other_g_to_t); USING(schnorr_G); // temps: temp0 result - CHECK(d0_bignum_mod_pow(temp0, ctx->other_4_to_r, ctx->r, ctx->schnorr_G)); - return d0_longhash_destructive(temp0, outbuf, outbuflen); + CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G)); + return d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen); fail: return 0; @@ -984,3 +1233,11 @@ void d0_blind_id_free(d0_blind_id_t *a) d0_blind_id_clear(a); d0_free(a); } + +void d0_blind_id_util_sha256(char *out, const char *in, size_t n) +{ + SHA256_CTX context; + SHA256_Init(&context); + SHA256_Update(&context, (const unsigned char *) in, n); + return SHA256_Final((unsigned char *) out, &context); +}