+/*
+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
+*/
+
#include "d0_blind_id.h"
#include <stdio.h>
#include <string.h>
#include "d0_bignum.h"
-#include "sha1.h"
+#include "sha2.h"
+
+// our SHA is SHA-256
+#define SHA_DIGESTSIZE 32
+const char *sha(const char *in, size_t len)
+{
+ static char h[32];
+ d0_blind_id_util_sha256(h, 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 :(
#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
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_4_to_s_signature;
+ 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 *rn; // random number blind signature
+ d0_bignum_t *rsa_blind_signature_camouflage; // random number blind signature
+
d0_bignum_t *r; // random number for schnorr ID
- char xnbh[SCHNORR_HASHSIZE]; // init hash
- d0_bignum_t *e; // challenge
+ 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
char msg[MSGSIZE]; // message
size_t msglen; // message length
};
#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 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_blind_id_INITIALIZE(void)
{
d0_bignum_INITIALIZE();
CHECK_ASSIGN(zero, d0_bignum_int(zero, 0));
;
}
-void d0_blind_id_SHUTDOWN()
+void d0_blind_id_SHUTDOWN(void)
{
d0_bignum_free(zero);
d0_bignum_free(one);
return 0;
}
-BOOL d0_rsa_generate_key(size_t size, const d0_bignum_t *e, d0_bignum_t *d, d0_bignum_t *n)
+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;
int gcdfail = 0;
- if(size < 16)
- size = 16;
int pb = (size + 1)/2;
int qb = size - pb;
+ if(pb < 8)
+ pb = 8;
+ if(qb < 8)
+ qb = 8;
for (;;)
{
CHECK(d0_bignum_rand_bit_exact(temp0, pb));
if(d0_bignum_isprime(temp0, 10) == 0)
continue;
CHECK(d0_bignum_sub(temp2, temp0, one));
- CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, e));
+ CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, challenge));
if(!d0_bignum_cmp(temp4, one))
break;
if(++gcdfail == 3)
if(d0_bignum_isprime(temp1, 10) == 0)
continue;
CHECK(d0_bignum_sub(temp3, temp1, one));
- CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, e));
+ CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, challenge));
if(!d0_bignum_cmp(temp4, one))
break;
if(++gcdfail == 3)
// n = temp0*temp1
CHECK(d0_bignum_mul(n, temp0, temp1));
-
- // d = e^-1 mod (temp0-1)(temp1-1)
+
+ // d = challenge^-1 mod (temp0-1)(temp1-1)
+ CHECK(d0_bignum_mul(temp0, temp2, temp3));
+ CHECK(d0_bignum_mod_inv(d, challenge, temp0));
+ return 1;
+fail:
+ return 0;
+}
+
+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;
+ int gcdfail = 0;
+ int pb = (size + 1)/2;
+ int qb = size - pb;
+ if(pb < 8)
+ pb = 8;
+ if(qb < 8)
+ qb = 8;
+ for (;;)
+ {
+ CHECK(d0_bignum_rand_bit_exact(temp0, pb));
+ if(d0_bignum_isprime(temp0, 10) == 0)
+ continue;
+ CHECK(d0_bignum_sub(temp2, temp0, one));
+ CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
+ if(!d0_bignum_cmp(temp4, one))
+ break;
+ if(++gcdfail == 3)
+ return 0;
+ ++gcdfail;
+ }
+ gcdfail = 0;
+ for (;;)
+ {
+ CHECK(d0_bignum_rand_bit_exact(temp1, qb));
+ if(!d0_bignum_cmp(temp1, temp0))
+ {
+ if(++fail == 3)
+ return 0;
+ }
+ fail = 0;
+
+ // n = temp0*temp1
+ CHECK(d0_bignum_mul(ctx->rsa_n, temp0, temp1));
+ if(reject(ctx, pass))
+ continue;
+
+ if(d0_bignum_isprime(temp1, 10) == 0)
+ continue;
+ CHECK(d0_bignum_sub(temp3, temp1, one));
+ CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
+ if(!d0_bignum_cmp(temp4, one))
+ break;
+ if(++gcdfail == 3)
+ return 0;
+ ++gcdfail;
+ }
+
+ // ctx->rsa_d = ctx->rsa_e^-1 mod (temp0-1)(temp1-1)
CHECK(d0_bignum_mul(temp0, temp2, temp3));
- CHECK(d0_bignum_mod_inv(d, e, temp0));
+ CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
+ return 1;
+fail:
+ return 0;
+}
+
+WARN_UNUSED_RESULT BOOL d0_longhash_destructive(d0_bignum_t *clobberme, char *outbuf, size_t outbuflen)
+{
+ d0_iobuf_t *out = NULL;
+ static unsigned char convbuf[1024];
+ size_t n, sz;
+
+ n = outbuflen;
+ while(n > SHA_DIGESTSIZE)
+ {
+ sz = (d0_bignum_size(clobberme) + 7) / 8;
+ CHECK(d0_bignum_export_unsigned(clobberme, convbuf, sizeof(convbuf)) >= 0);
+ memcpy(outbuf, sha(convbuf, sz), SHA_DIGESTSIZE);
+ outbuf += SHA_DIGESTSIZE;
+ n -= SHA_DIGESTSIZE;
+ CHECK(d0_bignum_add(clobberme, clobberme, one));
+ }
+ sz = (d0_bignum_size(clobberme) + 7) / 8;
+ CHECK(d0_bignum_export_unsigned(clobberme, convbuf, sizeof(convbuf)) >= 0);
+ memcpy(outbuf, sha(convbuf, sz), n);
return 1;
+
fail:
return 0;
}
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_4_to_s_signature) d0_bignum_free(ctx->schnorr_4_to_s_signature);
- if(ctx->rn) d0_bignum_free(ctx->rn);
+ 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->e) d0_bignum_free(ctx->e);
+ if(ctx->challenge) d0_bignum_free(ctx->challenge);
+ 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));
}
-void d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
+WARN_UNUSED_RESULT 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) ctx->rsa_n = d0_bignum_mov(NULL, src->rsa_n);
- if(src->rsa_e) ctx->rsa_e = d0_bignum_mov(NULL, src->rsa_e);
- if(src->rsa_d) ctx->rsa_d = d0_bignum_mov(NULL, src->rsa_d);
- if(src->schnorr_G) ctx->schnorr_G = d0_bignum_mov(NULL, src->schnorr_G);
- if(src->schnorr_s) ctx->schnorr_s = d0_bignum_mov(NULL, src->schnorr_s);
- if(src->schnorr_4_to_s) ctx->schnorr_4_to_s = d0_bignum_mov(NULL, ctx->schnorr_G);
- if(src->schnorr_4_to_s_signature) ctx->schnorr_4_to_s_signature = d0_bignum_mov(NULL, src->schnorr_4_to_s_signature);
- if(src->rn) ctx->rn = d0_bignum_mov(NULL, src->rn);
- if(src->r) ctx->r = d0_bignum_mov(NULL, src->r);
- if(src->e) ctx->e = d0_bignum_mov(NULL, src->e);
- // TODO xnbh, msg, msglen?
+ if(src->rsa_n) CHECK_ASSIGN(ctx->rsa_n, d0_bignum_mov(NULL, src->rsa_n));
+ if(src->rsa_e) CHECK_ASSIGN(ctx->rsa_e, d0_bignum_mov(NULL, src->rsa_e));
+ 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_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->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));
+ return 1;
+fail:
+ d0_blind_id_clear(ctx);
+ return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_keys(d0_blind_id_t *ctx, int k)
+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_blind_id_clear(ctx);
- CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_new());
- CHECK(d0_dl_generate_key(k, ctx->schnorr_G));
- CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(NULL, 65537));
- CHECK_ASSIGN(ctx->rsa_d, d0_bignum_new());
- CHECK_ASSIGN(ctx->rsa_n, d0_bignum_new());
- CHECK(d0_rsa_generate_key(k+1, ctx->rsa_e, ctx->rsa_d, ctx->rsa_n)); // must fit G for sure
+ REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
+
+ CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
+ CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
+ CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
+ if(reject)
+ CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
+ else
+ CHECK(d0_rsa_generate_key(k+1, ctx->rsa_e, ctx->rsa_d, ctx->rsa_n)); // must fit G for sure
return 1;
fail:
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_keys(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
{
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
- d0_blind_id_clear(ctx);
- CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, NULL));
- CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, NULL));
- CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, NULL));
- CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, NULL));
+ 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_iobuf_t *in = NULL;
+
+ REPLACING(rsa_n); REPLACING(rsa_e); REPLACING(rsa_d);
+
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+
+ CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
+ CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
+ CHECK_ASSIGN(ctx->rsa_d, d0_iobuf_read_bignum(in, ctx->rsa_d));
return d0_iobuf_close(in, NULL);
fail:
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_keys(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
{
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
- d0_blind_id_clear(ctx);
- CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, NULL));
- CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, NULL));
- CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, NULL));
+ d0_iobuf_t *in = NULL;
+
+ REPLACING(rsa_n); REPLACING(rsa_e);
+
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+ CHECK_ASSIGN(ctx->rsa_n, d0_iobuf_read_bignum(in, ctx->rsa_n));
+ CHECK_ASSIGN(ctx->rsa_e, d0_iobuf_read_bignum(in, ctx->rsa_e));
return d0_iobuf_close(in, NULL);
fail:
return 0;
}
-#define USING(x) if(!(ctx->x)) return 0
-#define WRITING(x,f) if(ctx->x) { f(ctx->x); ctx->x = NULL; }
-#define REPLACING(x)
-
-WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_keys(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
+ d0_iobuf_t *out = NULL;
+
USING(rsa_n); USING(rsa_e); USING(rsa_d);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
- CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
CHECK(d0_iobuf_write_bignum(out, ctx->rsa_d));
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_keys(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_key(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
- USING(rsa_n); USING(rsa_e); USING(rsa_d);
+ d0_iobuf_t *out = NULL;
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
- CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
+ USING(rsa_n); USING(rsa_e);
+
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
CHECK(d0_iobuf_write_bignum(out, ctx->rsa_n));
CHECK(d0_iobuf_write_bignum(out, ctx->rsa_e));
return d0_iobuf_close(out, outbuflen);
return 0;
}
+WARN_UNUSED_RESULT 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];
+ d0_iobuf_t *conv = NULL;
+ size_t sz, n;
+
+ USING(rsa_n); USING(rsa_e);
+
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
+ conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
+
+ CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_n));
+ CHECK(d0_iobuf_write_bignum(conv, ctx->rsa_e));
+ CHECK(d0_iobuf_close(conv, &sz));
+ conv = NULL;
+
+ n = (*outbuflen / 4) * 3;
+ if(n > SHA_DIGESTSIZE)
+ n = SHA_DIGESTSIZE;
+ CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), n) == n);
+ CHECK(d0_iobuf_conv_base64_out(out));
+
+ return d0_iobuf_close(out, outbuflen);
+
+fail:
+ if(conv)
+ d0_iobuf_close(conv, &sz);
+ d0_iobuf_close(out, outbuflen);
+ return 0;
+}
+
+WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_modulus(d0_blind_id_t *ctx)
+{
+ USING(rsa_n);
+ REPLACING(schnorr_G);
+
+ CHECK_ASSIGN(ctx->schnorr_G, d0_bignum_zero(ctx->schnorr_G));
+ CHECK(d0_dl_generate_key(d0_bignum_size(ctx->rsa_n)-1, ctx->schnorr_G));
+ return 1;
+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_iobuf_t *in = NULL;
+
+ REPLACING(schnorr_G);
+
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+ CHECK_ASSIGN(ctx->schnorr_G, d0_iobuf_read_bignum(in, ctx->schnorr_G));
+ return d0_iobuf_close(in, NULL);
+
+fail:
+ d0_iobuf_close(in, NULL);
+ 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_iobuf_t *out = NULL;
+
+ USING(schnorr_G);
+
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
+ CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_G));
+ return d0_iobuf_close(out, outbuflen);
+
+fail:
+ d0_iobuf_close(out, outbuflen);
+ return 0;
+}
+
WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_start(d0_blind_id_t *ctx)
{
- // temps: temp0 order
+ // 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_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_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:
WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
- // temps: temp0 temp1
- USING(rsa_n); USING(rsa_e); USING(schnorr_4_to_s);
- REPLACING(rn);
+ d0_iobuf_t *out = NULL;
+ static unsigned char convbuf[2048], 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_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));
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ // 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_destructive(temp2, shabuf, sz));
+ CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz));
- CHECK_ASSIGN(ctx->rn, d0_bignum_rand_bit_atmost(ctx->rn, d0_bignum_size(ctx->rsa_n)));
- CHECK(d0_bignum_mod_pow(temp0, ctx->rn, ctx->rsa_e, ctx->rsa_n));
- CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_4_to_s, temp0, ctx->rsa_n));
+ // hash complete
+ CHECK(d0_bignum_mod_mul(temp1, temp2, temp0, ctx->rsa_n));
CHECK(d0_iobuf_write_bignum(out, temp1));
return d0_iobuf_close(out, outbuflen);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_answer_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen)
+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)
{
- // temps: temp0 temp1
+ d0_iobuf_t *in = NULL;
+ d0_iobuf_t *out = NULL;
+
+ // temps: temp0 input, temp1 temp0^d
USING(rsa_d); USING(rsa_n);
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
CHECK(d0_iobuf_read_bignum(in, temp0));
CHECK(d0_bignum_mod_pow(temp1, temp0, ctx->rsa_d, ctx->rsa_n));
WARN_UNUSED_RESULT BOOL d0_blind_id_finish_private_id_request(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
{
- // temps: temp0 temp1
- USING(rn); USING(rsa_n);
- REPLACING(schnorr_4_to_s_signature);
+ 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_g_to_s_signature);
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
+ in = d0_iobuf_open_read(inbuf, inbuflen);
CHECK(d0_iobuf_read_bignum(in, temp0));
- CHECK(d0_bignum_mod_inv(temp1, ctx->rn, ctx->rsa_n));
- CHECK_ASSIGN(ctx->schnorr_4_to_s_signature, d0_bignum_mod_mul(ctx->schnorr_4_to_s_signature, temp0, temp1, ctx->rsa_n));
+ CHECK(d0_bignum_mod_inv(temp1, ctx->rsa_blind_signature_camouflage, 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);
+
+fail:
+ d0_iobuf_close(in, NULL);
+ 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_iobuf_t *in = NULL;
+
+ REPLACING(rsa_blind_signature_camouflage);
+
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+
+ CHECK_ASSIGN(ctx->rsa_blind_signature_camouflage, d0_iobuf_read_bignum(in, ctx->rsa_blind_signature_camouflage));
return d0_iobuf_close(in, NULL);
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_iobuf_t *out = NULL;
+
+ USING(rsa_blind_signature_camouflage);
+
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
+
+ CHECK(d0_iobuf_write_bignum(out, ctx->rsa_blind_signature_camouflage));
+
+ return d0_iobuf_close(out, outbuflen);
+
+fail:
+ d0_iobuf_close(out, outbuflen);
+ return 0;
+}
+
WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
{
- REPLACING(schnorr_s); REPLACING(schnorr_4_to_s); REPLACING(schnorr_4_to_s_signature);
+ d0_iobuf_t *in = NULL;
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
+ 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_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_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);
WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_id(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
{
- REPLACING(schnorr_4_to_s); REPLACING(schnorr_4_to_s_signature);
+ d0_iobuf_t *in = NULL;
+
+ REPLACING(schnorr_g_to_s); REPLACING(schnorr_H_g_to_s_signature);
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
+ 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_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_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);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_id(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
- USING(schnorr_s); USING(schnorr_4_to_s); USING(schnorr_4_to_s_signature);
+ d0_iobuf_t *out = NULL;
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ 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_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);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_id(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_write_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
- USING(schnorr_4_to_s); USING(schnorr_4_to_s_signature);
+ d0_iobuf_t *out = NULL;
+
+ USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ 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_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);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_id_t *ctx, int is_first, char *msg, size_t msglen, char *outbuf, size_t *outbuflen)
+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)
// start =
// first run: send 4^s, 4^s signature
// 1. get random r, send HASH(4^r)
{
+ d0_iobuf_t *out = NULL;
+ static unsigned char convbuf[1024];
+ d0_iobuf_t *conv = NULL;
+ size_t sz = 0;
+
+ // temps: temp0 order, temp0 4^r
if(is_first)
{
- USING(schnorr_4_to_s); USING(schnorr_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);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
if(is_first)
{
// send ID
- CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_4_to_s));
- CHECK(d0_iobuf_write_bignum(out, ctx->schnorr_4_to_s_signature));
+ 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 ID scheme
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
+ CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
+ CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp1));
+ CHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G));
+ // can we SOMEHOW do this with just one mod_pow?
+
// hash it, hash it, everybody hash it
- unsigned char convbuf[1024];
- d0_iobuf_t *conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
- size_t sz;
+ 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);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_blind_id_t *ctx, int is_first, const char *inbuf, size_t inbuflen, char *outbuf, size_t *outbuflen)
+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)
// first run: get 4^s, 4^s signature
// 1. check sig
// 2. save HASH(4^r)
-// 3. send challenge e of SCHNORR_BITS
+// 3. send challenge challenge of SCHNORR_BITS
{
+ d0_iobuf_t *in = NULL;
+ d0_iobuf_t *out = NULL;
+ static unsigned char shabuf[2048];
+ size_t sz;
+
+ // temps: temp0 order, temp0 signature check
if(is_first)
{
- REPLACING(schnorr_4_to_s); REPLACING(k); REPLACING(schnorr_4_to_s_signature);
- USING(schnorr_G); USING(rsa_n);
+ 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_4_to_s_signature); USING(schnorr_4_to_s);
+ USING(schnorr_g_to_s); USING(schnorr_H_g_to_s_signature);
+ USING(schnorr_G);
}
USING(rsa_e); USING(rsa_n);
- REPLACING(e); REPLACING(msg); REPLACING(msglen);
+ REPLACING(challenge); REPLACING(msg); REPLACING(msglen); REPLACING(msghash); REPLACING(r); REPLACING(t);
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ in = d0_iobuf_open_read(inbuf, inbuflen);
+ out = d0_iobuf_open_write(outbuf, *outbuflen);
if(is_first)
{
- CHECK_ASSIGN(ctx->schnorr_4_to_s, d0_iobuf_read_bignum(in, NULL));
- 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_4_to_s_signature, d0_iobuf_read_bignum(in, ctx->schnorr_4_to_s_signature));
- CHECK(d0_bignum_cmp(ctx->schnorr_4_to_s_signature, zero) >= 0);
- CHECK(d0_bignum_cmp(ctx->schnorr_4_to_s_signature, ctx->rsa_n) < 0);
- }
-
- // check signature of key (t = k^d, so, t^e = k)
- CHECK(d0_bignum_mod_pow(temp0, ctx->schnorr_4_to_s_signature, ctx->rsa_e, ctx->rsa_n));
- if(d0_bignum_cmp(temp0, ctx->schnorr_4_to_s))
- {
- // FAIL (not signed by Xonotic)
- goto fail;
- // TODO: accept the key anyway, but mark as failed signature!
+ 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_destructive(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_iobuf_read_raw(in, ctx->xnbh, SCHNORR_HASHSIZE));
+ CHECK(d0_iobuf_read_raw(in, ctx->msghash, SCHNORR_HASHSIZE));
ctx->msglen = MSGSIZE;
CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen));
// send challenge
- CHECK_ASSIGN(ctx->e, d0_bignum_rand_bit_atmost(ctx->e, SCHNORR_BITS));
+ CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS));
+ CHECK(d0_iobuf_write_bignum(out, ctx->challenge));
- CHECK(d0_iobuf_write_bignum(out, ctx->e));
+ // Diffie Hellmann send
+ CHECK(d0_dl_get_order(temp0, 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_g_to_s_signature, zero);
d0_iobuf_close(in, NULL);
return d0_iobuf_close(out, outbuflen);
}
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)
-// 1. read challenge e of SCHNORR_BITS
-// 2. reply with r + s * e mod order
+// 1. read challenge challenge of SCHNORR_BITS
+// 2. reply with r + s * challenge mod order
{
- // temps: 0 order, 1 prod, 2 y, 3 e
- USING(schnorr_G); USING(schnorr_s); USING(r);
+ d0_iobuf_t *in = NULL;
+ d0_iobuf_t *out = NULL;
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
+ // temps: 0 order, 1 prod, 2 y, 3 challenge
+ 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);
CHECK(d0_iobuf_read_bignum(in, temp3));
- // TODO check if >= 2^SCHNORR_BITS or < 0, if yes, then fail (needed for zero knowledge)
CHECK(d0_bignum_cmp(temp3, zero) >= 0);
CHECK(d0_bignum_size(temp3) <= SCHNORR_BITS);
// send response for schnorr ID scheme
- // i.e. r + ctx->schnorr_s * temp3
+ // i.challenge. r + ctx->schnorr_s * temp3
CHECK(d0_dl_get_order(temp0, ctx->schnorr_G));
CHECK(d0_bignum_mod_mul(temp1, ctx->schnorr_s, temp3, temp0));
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);
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, ssize_t *msglen)
-// 1. read y = r + s * e mod order
-// 2. verify: g^y (g^s)^-e = g^(r+s*e-s*e) = g^r
+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)
+// 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)
{
+ d0_iobuf_t *in = NULL;
+ static unsigned char convbuf[1024];
+ d0_iobuf_t *conv = NULL;
+ size_t sz;
+
// temps: 0 y 1 order
- USING(e); USING(schnorr_G);
+ USING(challenge); USING(schnorr_G);
+ REPLACING(other_g_to_t);
- d0_iobuf_t *in = d0_iobuf_open_read(inbuf, inbuflen);
+ in = d0_iobuf_open_read(inbuf, inbuflen);
- *msglen = -1;
CHECK(d0_dl_get_order(temp1, ctx->schnorr_G));
CHECK(d0_iobuf_read_bignum(in, temp0));
CHECK(d0_bignum_cmp(temp0, zero) >= 0);
CHECK(d0_bignum_cmp(temp0, temp1) < 0);
// verify schnorr ID scheme
- // we need 4^temp0 (g^s)^-e
- CHECK(d0_bignum_neg(temp1, ctx->e));
- 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(d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));
- // hash must be equal to xnbh
+ 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
- unsigned char convbuf[1024];
- d0_iobuf_t *conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
- size_t sz;
+ conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
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, 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->xnbh, SCHNORR_HASHSIZE))
+ if(memcmp(sha(convbuf, sz), ctx->msghash, SCHNORR_HASHSIZE))
{
// FAIL (not owned by player)
goto fail;
}
- if(ctx->msglen <= (size_t) *msglen)
+ if(status)
+ *status = !!d0_bignum_cmp(ctx->schnorr_H_g_to_s_signature, zero);
+
+ if(ctx->msglen <= *msglen)
memcpy(msg, ctx->msg, ctx->msglen);
else
memcpy(msg, ctx->msg, *msglen);
return 0;
}
-WARN_UNUSED_RESULT BOOL d0_blind_id_fingerprint64_public_id(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+WARN_UNUSED_RESULT BOOL d0_blind_id_fingerprint64_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
{
- USING(schnorr_4_to_s);
-
+ d0_iobuf_t *out = NULL;
static unsigned char convbuf[1024];
- d0_iobuf_t *out = d0_iobuf_open_write(outbuf, *outbuflen);
- d0_iobuf_t *conv = d0_iobuf_open_write(convbuf, sizeof(convbuf));
+ d0_iobuf_t *conv = NULL;
+ size_t sz, n;
- size_t n, sz;
+ 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->schnorr_g_to_s));
CHECK(d0_iobuf_close(conv, &sz));
conv = NULL;
n = (*outbuflen / 4) * 3;
if(n > SHA_DIGESTSIZE)
n = SHA_DIGESTSIZE;
- if(d0_iobuf_write_raw(out, sha(convbuf, sz), n) != n)
- goto fail;
- if(!d0_iobuf_conv_base64_out(out))
- goto fail;
+ CHECK(d0_iobuf_write_raw(out, sha(convbuf, sz), n) == n);
+ CHECK(d0_iobuf_conv_base64_out(out));
return d0_iobuf_close(out, outbuflen);
fail:
if(conv)
- if(!d0_iobuf_close(conv, &sz)) { }
- if(!d0_iobuf_close(out, outbuflen))
- return 0;
+ d0_iobuf_close(conv, &sz);
+ d0_iobuf_close(out, outbuflen);
+ return 0;
+}
+
+BOOL d0_blind_id_sessionkey_public_id(const d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen)
+{
+ USING(t); USING(other_g_to_t); USING(schnorr_G);
+
+ // temps: temp0 result
+ CHECK(d0_bignum_mod_pow(temp0, ctx->other_g_to_t, ctx->t, ctx->schnorr_G));
+ return d0_longhash_destructive(temp0, outbuf, *outbuflen);
+
+fail:
return 0;
}
-d0_blind_id_t *d0_blind_id_new()
+d0_blind_id_t *d0_blind_id_new(void)
{
d0_blind_id_t *b = d0_malloc(sizeof(d0_blind_id_t));
memset(b, 0, sizeof(*b));
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);
+}
projects / xonotic / d0_blind_id.git / blobdiff