X-Git-Url: https://git.xonotic.org/?a=blobdiff_plain;f=d0_blind_id.c;h=a02aaa7c7cde0a8bce248f7ffaac7ed323f7d950;hb=3bbb5d321d26e8fc65e531196384e5a0430593a6;hp=be590687bec27465c795d93237f9f13212aea690;hpb=e3538b62b2f683cdec6a8e93d4bc59c415e605ae;p=xonotic%2Fd0_blind_id.git diff --git a/d0_blind_id.c b/d0_blind_id.c index be59068..a02aaa7 100644 --- a/d0_blind_id.c +++ b/d0_blind_id.c @@ -29,7 +29,8 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * - * $Format:commit %H$, $Id$ + * $Format:commit %H$ + * $Id$ */ #include "d0_blind_id.h" @@ -39,12 +40,15 @@ #include "d0_bignum.h" #include "sha2.h" +// old "positive" protocol, uses one extra mod_inv in verify stages +// #define D0_BLIND_ID_POSITIVE_PROTOCOL + // our SHA is SHA-256 #define SHA_DIGESTSIZE 32 -const char *sha(const char *in, size_t len) +const char *sha(const unsigned char *in, size_t len) { static char h[32]; - d0_blind_id_util_sha256(h, in, len); + d0_blind_id_util_sha256(h, (const char *) in, len); return h; } @@ -93,17 +97,21 @@ struct d0_blind_id_s size_t msglen; // message length }; +//#define CHECKDEBUG +#ifdef CHECKDEBUG +#define CHECK(x) do { if(!(x)) { fprintf(stderr, "CHECK FAILED (%s:%d): %s\n", __FILE__, __LINE__, #x); goto fail; } } while(0) +#define CHECK_ASSIGN(var, value) do { d0_bignum_t *val; val = value; if(!val) { fprintf(stderr, "CHECK FAILED (%s:%d): %s\n", __FILE__, __LINE__, #value); goto fail; } var = val; } while(0) +#else #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) +#endif #define USING(x) if(!(ctx->x)) return 0 #define REPLACING(x) static d0_bignum_t *zero, *one, *four, *temp0, *temp1, *temp2, *temp3, *temp4; -WARN_UNUSED_RESULT BOOL d0_blind_id_INITIALIZE(void) +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_INITIALIZE(void) { CHECK(d0_bignum_INITIALIZE()); CHECK_ASSIGN(zero, d0_bignum_int(zero, 0)); @@ -151,7 +159,7 @@ 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) @@ -173,7 +181,7 @@ 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; @@ -229,7 +237,7 @@ 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; @@ -288,26 +296,33 @@ 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]; - size_t n, sz; + size_t n, i; 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)); + for(i = 0; i < sz; ++i) + if(++convbuf[i]) + break; // stop until no carry } - 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; +} + +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: return 0; @@ -331,7 +346,7 @@ void d0_blind_id_clear(d0_blind_id_t *ctx) 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)); @@ -356,7 +371,7 @@ 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); @@ -372,12 +387,12 @@ 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; @@ -395,7 +410,7 @@ 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; @@ -411,7 +426,7 @@ 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; @@ -428,7 +443,7 @@ 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; @@ -445,7 +460,7 @@ 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]; @@ -477,7 +492,7 @@ 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); @@ -489,7 +504,7 @@ 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; @@ -504,7 +519,7 @@ 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; @@ -519,7 +534,7 @@ 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); @@ -535,10 +550,10 @@ 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], shabuf[2048]; + static unsigned char shabuf[2048]; size_t sz; // temps: temp0 rsa_blind_signature_camouflage^challenge, temp1 (4^s)*rsa_blind_signature_camouflage^challenge @@ -555,7 +570,7 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_id_request(d0_blind_id_t *c 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_longhash_bignum(temp2, shabuf, sz)); CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); // hash complete @@ -568,7 +583,7 @@ 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; @@ -592,7 +607,7 @@ 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; @@ -613,7 +628,7 @@ 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; @@ -630,7 +645,7 @@ 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; @@ -647,7 +662,7 @@ 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; @@ -666,7 +681,7 @@ 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; @@ -684,7 +699,7 @@ 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; @@ -703,7 +718,7 @@ 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; @@ -721,7 +736,7 @@ 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) @@ -730,7 +745,7 @@ 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; - BOOL failed = 0; + D0_BOOL failed = 0; // temps: temp0 order, temp0 4^r if(is_first) @@ -754,16 +769,23 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_start(d0_blind_ // 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)); +#ifdef RNG_XKCD + CHECK_ASSIGN(ctx->r, d0_bignum_int(ctx->r, 4)); // decided by fair dice roll +#else CHECK_ASSIGN(ctx->r, d0_bignum_rand_range(ctx->r, zero, temp0)); - //CHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G)); +#endif // initialize Signed Diffie Hellmann // we already have the group order in temp1 +#ifdef RNG_XKCD + CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll +#else CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0)); +#endif // can we SOMEHOW do this with just one mod_pow? - MPCHECK(d0_bignum_mod_pow(temp0, four, ctx->r, ctx->schnorr_G)); - MPCHECK_ASSIGN(ctx->g_to_t, d0_bignum_mod_pow(ctx->g_to_t, four, ctx->t, ctx->schnorr_G)); + 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 @@ -785,7 +807,7 @@ 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) @@ -839,7 +861,7 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl 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_longhash_bignum(temp2, shabuf, sz)); CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); // + 7 / 8 is too large, so let's mod it @@ -858,12 +880,20 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_challenge(d0_bl CHECK(d0_iobuf_read_packet(in, ctx->msg, &ctx->msglen)); // send challenge +#ifdef RNG_XKCD + CHECK_ASSIGN(ctx->challenge, d0_bignum_int(ctx->challenge, 4)); // decided by fair dice roll +#else CHECK_ASSIGN(ctx->challenge, d0_bignum_rand_bit_atmost(ctx->challenge, SCHNORR_BITS)); +#endif CHECK(d0_iobuf_write_bignum(out, ctx->challenge)); // Diffie Hellmann send CHECK(d0_dl_get_order(temp0, ctx->schnorr_G)); +#ifdef RNG_XKCD + CHECK_ASSIGN(ctx->t, d0_bignum_int(ctx->t, 4)); // decided by fair dice roll +#else CHECK_ASSIGN(ctx->t, d0_bignum_rand_range(ctx->t, zero, temp0)); +#endif CHECK(d0_bignum_mod_pow(temp0, four, ctx->t, ctx->schnorr_G)); CHECK(d0_iobuf_write_bignum(out, temp0)); @@ -879,7 +909,7 @@ 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 { @@ -901,7 +931,11 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_response(d0_bli // 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)); +#ifdef D0_BLIND_ID_POSITIVE_PROTOCOL + CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0)); +#else + CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0)); +#endif CHECK(d0_iobuf_write_bignum(out, temp2)); // Diffie Hellmann recv @@ -920,7 +954,7 @@ 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) @@ -942,9 +976,14 @@ 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 +#ifdef D0_BLIND_ID_POSITIVE_PROTOCOL // 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)); +#else + // we need 4^r = 4^temp0 (g^s)^challenge + CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_g_to_s, ctx->challenge, ctx->schnorr_G)); +#endif CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G)); CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G)); @@ -985,7 +1024,7 @@ fail: return 0; } -WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_generate_missing_signature(d0_blind_id_t *ctx) +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]; @@ -998,7 +1037,7 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_generate_missin 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_longhash_bignum(temp2, shabuf, sz)); CHECK(d0_bignum_import_unsigned(temp2, shabuf, sz)); // + 7 / 8 is too large, so let's mod it @@ -1010,7 +1049,190 @@ 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_sign_with_private_id_sign_internal(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, D0_BOOL with_msg, const char *message, size_t msglen, char *outbuf, size_t *outbuflen) +{ + 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)); +#ifdef D0_BLIND_ID_POSITIVE_PROTOCOL + CHECK(d0_bignum_mod_add(temp2, ctx->r, temp1, temp0)); +#else + CHECK(d0_bignum_mod_sub(temp2, ctx->r, temp1, temp0)); +#endif + CHECK(d0_iobuf_write_bignum(out, temp2)); + + // write the message itself + if(with_msg) + 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_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) +{ + return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 1, message, msglen, outbuf, outbuflen); +} +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_sign_detached(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL send_modulus, const char *message, size_t msglen, char *outbuf, size_t *outbuflen) +{ + return d0_blind_id_sign_with_private_id_sign_internal(ctx, is_first, send_modulus, 0, message, msglen, outbuf, outbuflen); +} + +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_verify_internal(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, D0_BOOL with_msg, const char *inbuf, size_t inbuflen, char *msg, size_t *msglen, D0_BOOL *status) +{ + 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| + if(with_msg) + 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)); +#ifdef D0_BLIND_ID_POSITIVE_PROTOCOL + CHECK(d0_bignum_mod_inv(temp3, ctx->schnorr_g_to_s, ctx->schnorr_G)); + CHECK(d0_bignum_mod_pow(temp1, temp3, temp0, ctx->schnorr_G)); +#else + CHECK(d0_bignum_mod_pow(temp1, ctx->schnorr_g_to_s, temp0, ctx->schnorr_G)); +#endif + 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_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) +{ + return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 1, inbuf, inbuflen, msg, msglen, status); +} +D0_WARN_UNUSED_RESULT D0_BOOL d0_blind_id_sign_with_private_id_verify_detached(d0_blind_id_t *ctx, D0_BOOL is_first, D0_BOOL recv_modulus, const char *inbuf, size_t inbuflen, const char *msg, size_t msglen, D0_BOOL *status) +{ + return d0_blind_id_sign_with_private_id_verify_internal(ctx, is_first, recv_modulus, 0, inbuf, inbuflen, (char *) msg, &msglen, status); +} + +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]; @@ -1045,13 +1267,13 @@ 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(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); + return d0_longhash_bignum(temp0, (unsigned char *) outbuf, *outbuflen); fail: return 0;