diff options
Diffstat (limited to 'plugins/MirOTR/Libgcrypt/cipher/ecc.c')
-rw-r--r-- | plugins/MirOTR/Libgcrypt/cipher/ecc.c | 1390 |
1 files changed, 1390 insertions, 0 deletions
diff --git a/plugins/MirOTR/Libgcrypt/cipher/ecc.c b/plugins/MirOTR/Libgcrypt/cipher/ecc.c new file mode 100644 index 0000000000..fcbd8e3a9d --- /dev/null +++ b/plugins/MirOTR/Libgcrypt/cipher/ecc.c @@ -0,0 +1,1390 @@ +/* ecc.c - Elliptic Curve Cryptography + Copyright (C) 2007, 2008 Free Software Foundation, Inc. + + This file is part of Libgcrypt. + + Libgcrypt 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. + + Libgcrypt 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 program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, + USA. */ + +/* This code is originally based on the Patch 0.1.6 for the gnupg + 1.4.x branch as retrieved on 2007-03-21 from + http://www.calcurco.cat/eccGnuPG/src/gnupg-1.4.6-ecc0.2.0beta1.diff.bz2 + The original authors are: + Written by + Sergi Blanch i Torne <d4372211 at alumnes.eup.udl.es>, + Ramiro Moreno Chiral <ramiro at eup.udl.es> + Maintainers + Sergi Blanch i Torne + Ramiro Moreno Chiral + Mikael Mylnikov (mmr) + For use in Libgcrypt the code has been heavily modified and cleaned + up. In fact there is not much left of the orginally code except for + some variable names and the text book implementaion of the sign and + verification algorithms. The arithmetic functions have entirely + been rewritten and moved to mpi/ec.c. */ + + +/* TODO: + + - If we support point compression we need to decide how to compute + the keygrip - it should not change due to compression. + + - In mpi/ec.c we use mpi_powm for x^2 mod p: Either implement a + special case in mpi_powm or check whether mpi_mulm is faster. + + - Decide whether we should hide the mpi_point_t definition. + + - Support more than just ECDSA. +*/ + + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "g10lib.h" +#include "mpi.h" +#include "cipher.h" + + +/* Definition of a curve. */ +typedef struct +{ + gcry_mpi_t p; /* Prime specifying the field GF(p). */ + gcry_mpi_t a; /* First coefficient of the Weierstrass equation. */ + gcry_mpi_t b; /* Second coefficient of the Weierstrass equation. */ + mpi_point_t G; /* Base point (generator). */ + gcry_mpi_t n; /* Order of G. */ +} elliptic_curve_t; + + +typedef struct +{ + elliptic_curve_t E; + mpi_point_t Q; /* Q = [d]G */ +} ECC_public_key; + +typedef struct +{ + elliptic_curve_t E; + mpi_point_t Q; + gcry_mpi_t d; +} ECC_secret_key; + + +/* This tables defines aliases for curve names. */ +static const struct +{ + const char *name; /* Our name. */ + const char *other; /* Other name. */ +} curve_aliases[] = + { + { "NIST P-192", "1.2.840.10045.3.1.1" }, /* X9.62 OID */ + { "NIST P-192", "prime192v1" }, /* X9.62 name. */ + { "NIST P-192", "secp192r1" }, /* SECP name. */ + + { "NIST P-224", "secp224r1" }, + { "NIST P-224", "1.3.132.0.33" }, /* SECP OID. */ + + { "NIST P-256", "1.2.840.10045.3.1.7" }, /* From NIST SP 800-78-1. */ + { "NIST P-256", "prime256v1" }, + { "NIST P-256", "secp256r1" }, + + { "NIST P-384", "secp384r1" }, + { "NIST P-384", "1.3.132.0.34" }, + + { "NIST P-521", "secp521r1" }, + { "NIST P-521", "1.3.132.0.35" }, + + { "brainpoolP160r1", "1.3.36.3.3.2.8.1.1.1" }, + { "brainpoolP192r1", "1.3.36.3.3.2.8.1.1.3" }, + { "brainpoolP224r1", "1.3.36.3.3.2.8.1.1.5" }, + { "brainpoolP256r1", "1.3.36.3.3.2.8.1.1.7" }, + { "brainpoolP320r1", "1.3.36.3.3.2.8.1.1.9" }, + { "brainpoolP384r1", "1.3.36.3.3.2.8.1.1.11"}, + { "brainpoolP512r1", "1.3.36.3.3.2.8.1.1.13"}, + + { NULL, NULL} + }; + + + +/* This static table defines all available curves. */ +static const struct +{ + const char *desc; /* Description of the curve. */ + unsigned int nbits; /* Number of bits. */ + unsigned int fips:1; /* True if this is a FIPS140-2 approved curve. */ + const char *p; /* Order of the prime field. */ + const char *a, *b; /* The coefficients. */ + const char *n; /* The order of the base point. */ + const char *g_x, *g_y; /* Base point. */ +} domain_parms[] = + { + { + "NIST P-192", 192, 1, + "0xfffffffffffffffffffffffffffffffeffffffffffffffff", + "0xfffffffffffffffffffffffffffffffefffffffffffffffc", + "0x64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1", + "0xffffffffffffffffffffffff99def836146bc9b1b4d22831", + + "0x188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012", + "0x07192b95ffc8da78631011ed6b24cdd573f977a11e794811" + }, + { + "NIST P-224", 224, 1, + "0xffffffffffffffffffffffffffffffff000000000000000000000001", + "0xfffffffffffffffffffffffffffffffefffffffffffffffffffffffe", + "0xb4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4", + "0xffffffffffffffffffffffffffff16a2e0b8f03e13dd29455c5c2a3d" , + + "0xb70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21", + "0xbd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34" + }, + { + "NIST P-256", 256, 1, + "0xffffffff00000001000000000000000000000000ffffffffffffffffffffffff", + "0xffffffff00000001000000000000000000000000fffffffffffffffffffffffc", + "0x5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b", + "0xffffffff00000000ffffffffffffffffbce6faada7179e84f3b9cac2fc632551", + + "0x6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296", + "0x4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5" + }, + { + "NIST P-384", 384, 1, + "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe" + "ffffffff0000000000000000ffffffff", + "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe" + "ffffffff0000000000000000fffffffc", + "0xb3312fa7e23ee7e4988e056be3f82d19181d9c6efe8141120314088f5013875a" + "c656398d8a2ed19d2a85c8edd3ec2aef", + "0xffffffffffffffffffffffffffffffffffffffffffffffffc7634d81f4372ddf" + "581a0db248b0a77aecec196accc52973", + + "0xaa87ca22be8b05378eb1c71ef320ad746e1d3b628ba79b9859f741e082542a38" + "5502f25dbf55296c3a545e3872760ab7", + "0x3617de4a96262c6f5d9e98bf9292dc29f8f41dbd289a147ce9da3113b5f0b8c0" + "0a60b1ce1d7e819d7a431d7c90ea0e5f" + }, + { + "NIST P-521", 521, 1, + "0x01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" + "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", + "0x01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" + "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc", + "0x051953eb9618e1c9a1f929a21a0b68540eea2da725b99b315f3b8b489918ef10" + "9e156193951ec7e937b1652c0bd3bb1bf073573df883d2c34f1ef451fd46b503f00", + "0x1fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" + "ffa51868783bf2f966b7fcc0148f709a5d03bb5c9b8899c47aebb6fb71e91386409", + + "0xc6858e06b70404e9cd9e3ecb662395b4429c648139053fb521f828af606b4d3d" + "baa14b5e77efe75928fe1dc127a2ffa8de3348b3c1856a429bf97e7e31c2e5bd66", + "0x11839296a789a3bc0045c8a5fb42c7d1bd998f54449579b446817afbd17273e6" + "62c97ee72995ef42640c550b9013fad0761353c7086a272c24088be94769fd16650" + }, + + { "brainpoolP160r1", 160, 0, + "0xe95e4a5f737059dc60dfc7ad95b3d8139515620f", + "0x340e7be2a280eb74e2be61bada745d97e8f7c300", + "0x1e589a8595423412134faa2dbdec95c8d8675e58", + "0xe95e4a5f737059dc60df5991d45029409e60fc09", + "0xbed5af16ea3f6a4f62938c4631eb5af7bdbcdbc3", + "0x1667cb477a1a8ec338f94741669c976316da6321" + }, + + { "brainpoolP192r1", 192, 0, + "0xc302f41d932a36cda7a3463093d18db78fce476de1a86297", + "0x6a91174076b1e0e19c39c031fe8685c1cae040e5c69a28ef", + "0x469a28ef7c28cca3dc721d044f4496bcca7ef4146fbf25c9", + "0xc302f41d932a36cda7a3462f9e9e916b5be8f1029ac4acc1", + "0xc0a0647eaab6a48753b033c56cb0f0900a2f5c4853375fd6", + "0x14b690866abd5bb88b5f4828c1490002e6773fa2fa299b8f" + }, + + { "brainpoolP224r1", 224, 0, + "0xd7c134aa264366862a18302575d1d787b09f075797da89f57ec8c0ff", + "0x68a5e62ca9ce6c1c299803a6c1530b514e182ad8b0042a59cad29f43", + "0x2580f63ccfe44138870713b1a92369e33e2135d266dbb372386c400b", + "0xd7c134aa264366862a18302575d0fb98d116bc4b6ddebca3a5a7939f", + "0x0d9029ad2c7e5cf4340823b2a87dc68c9e4ce3174c1e6efdee12c07d", + "0x58aa56f772c0726f24c6b89e4ecdac24354b9e99caa3f6d3761402cd" + }, + + { "brainpoolP256r1", 256, 0, + "0xa9fb57dba1eea9bc3e660a909d838d726e3bf623d52620282013481d1f6e5377", + "0x7d5a0975fc2c3057eef67530417affe7fb8055c126dc5c6ce94a4b44f330b5d9", + "0x26dc5c6ce94a4b44f330b5d9bbd77cbf958416295cf7e1ce6bccdc18ff8c07b6", + "0xa9fb57dba1eea9bc3e660a909d838d718c397aa3b561a6f7901e0e82974856a7", + "0x8bd2aeb9cb7e57cb2c4b482ffc81b7afb9de27e1e3bd23c23a4453bd9ace3262", + "0x547ef835c3dac4fd97f8461a14611dc9c27745132ded8e545c1d54c72f046997" + }, + + { "brainpoolP320r1", 320, 0, + "0xd35e472036bc4fb7e13c785ed201e065f98fcfa6f6f40def4f92b9ec7893ec28" + "fcd412b1f1b32e27", + "0x3ee30b568fbab0f883ccebd46d3f3bb8a2a73513f5eb79da66190eb085ffa9f4" + "92f375a97d860eb4", + "0x520883949dfdbc42d3ad198640688a6fe13f41349554b49acc31dccd88453981" + "6f5eb4ac8fb1f1a6", + "0xd35e472036bc4fb7e13c785ed201e065f98fcfa5b68f12a32d482ec7ee8658e9" + "8691555b44c59311", + "0x43bd7e9afb53d8b85289bcc48ee5bfe6f20137d10a087eb6e7871e2a10a599c7" + "10af8d0d39e20611", + "0x14fdd05545ec1cc8ab4093247f77275e0743ffed117182eaa9c77877aaac6ac7" + "d35245d1692e8ee1" + }, + + { "brainpoolP384r1", 384, 0, + "0x8cb91e82a3386d280f5d6f7e50e641df152f7109ed5456b412b1da197fb71123" + "acd3a729901d1a71874700133107ec53", + "0x7bc382c63d8c150c3c72080ace05afa0c2bea28e4fb22787139165efba91f90f" + "8aa5814a503ad4eb04a8c7dd22ce2826", + "0x04a8c7dd22ce28268b39b55416f0447c2fb77de107dcd2a62e880ea53eeb62d5" + "7cb4390295dbc9943ab78696fa504c11", + "0x8cb91e82a3386d280f5d6f7e50e641df152f7109ed5456b31f166e6cac0425a7" + "cf3ab6af6b7fc3103b883202e9046565", + "0x1d1c64f068cf45ffa2a63a81b7c13f6b8847a3e77ef14fe3db7fcafe0cbd10e8" + "e826e03436d646aaef87b2e247d4af1e", + "0x8abe1d7520f9c2a45cb1eb8e95cfd55262b70b29feec5864e19c054ff9912928" + "0e4646217791811142820341263c5315" + }, + + { "brainpoolP512r1", 512, 0, + "0xaadd9db8dbe9c48b3fd4e6ae33c9fc07cb308db3b3c9d20ed6639cca70330871" + "7d4d9b009bc66842aecda12ae6a380e62881ff2f2d82c68528aa6056583a48f3", + "0x7830a3318b603b89e2327145ac234cc594cbdd8d3df91610a83441caea9863bc" + "2ded5d5aa8253aa10a2ef1c98b9ac8b57f1117a72bf2c7b9e7c1ac4d77fc94ca", + "0x3df91610a83441caea9863bc2ded5d5aa8253aa10a2ef1c98b9ac8b57f1117a7" + "2bf2c7b9e7c1ac4d77fc94cadc083e67984050b75ebae5dd2809bd638016f723", + "0xaadd9db8dbe9c48b3fd4e6ae33c9fc07cb308db3b3c9d20ed6639cca70330870" + "553e5c414ca92619418661197fac10471db1d381085ddaddb58796829ca90069", + "0x81aee4bdd82ed9645a21322e9c4c6a9385ed9f70b5d916c1b43b62eef4d0098e" + "ff3b1f78e2d0d48d50d1687b93b97d5f7c6d5047406a5e688b352209bcb9f822", + "0x7dde385d566332ecc0eabfa9cf7822fdf209f70024a57b1aa000c55b881f8111" + "b2dcde494a5f485e5bca4bd88a2763aed1ca2b2fa8f0540678cd1e0f3ad80892" + }, + + { NULL, 0, 0, NULL, NULL, NULL, NULL } + }; + + +/* Registered progress function and its callback value. */ +static void (*progress_cb) (void *, const char*, int, int, int); +static void *progress_cb_data; + + +#define point_init(a) _gcry_mpi_ec_point_init ((a)) +#define point_free(a) _gcry_mpi_ec_point_free ((a)) + + + +/* Local prototypes. */ +static gcry_mpi_t gen_k (gcry_mpi_t p, int security_level); +static void test_keys (ECC_secret_key * sk, unsigned int nbits); +static int check_secret_key (ECC_secret_key * sk); +static gpg_err_code_t sign (gcry_mpi_t input, ECC_secret_key *skey, + gcry_mpi_t r, gcry_mpi_t s); +static gpg_err_code_t verify (gcry_mpi_t input, ECC_public_key *pkey, + gcry_mpi_t r, gcry_mpi_t s); + + +static gcry_mpi_t gen_y_2 (gcry_mpi_t x, elliptic_curve_t * base); + + + + +void +_gcry_register_pk_ecc_progress (void (*cb) (void *, const char *, + int, int, int), + void *cb_data) +{ + progress_cb = cb; + progress_cb_data = cb_data; +} + +/* static void */ +/* progress (int c) */ +/* { */ +/* if (progress_cb) */ +/* progress_cb (progress_cb_data, "pk_ecc", c, 0, 0); */ +/* } */ + + + + +/* Set the value from S into D. */ +static void +point_set (mpi_point_t *d, mpi_point_t *s) +{ + mpi_set (d->x, s->x); + mpi_set (d->y, s->y); + mpi_set (d->z, s->z); +} + + +/* + * Release a curve object. + */ +static void +curve_free (elliptic_curve_t *E) +{ + mpi_free (E->p); E->p = NULL; + mpi_free (E->a); E->a = NULL; + mpi_free (E->b); E->b = NULL; + point_free (&E->G); + mpi_free (E->n); E->n = NULL; +} + + +/* + * Return a copy of a curve object. + */ +static elliptic_curve_t +curve_copy (elliptic_curve_t E) +{ + elliptic_curve_t R; + + R.p = mpi_copy (E.p); + R.a = mpi_copy (E.a); + R.b = mpi_copy (E.b); + point_init (&R.G); + point_set (&R.G, &E.G); + R.n = mpi_copy (E.n); + + return R; +} + + + +/* Helper to scan a hex string. */ +static gcry_mpi_t +scanval (const char *string) +{ + gpg_error_t err; + gcry_mpi_t val; + + err = gcry_mpi_scan (&val, GCRYMPI_FMT_HEX, string, 0, NULL); + if (err) + log_fatal ("scanning ECC parameter failed: %s\n", gpg_strerror (err)); + return val; +} + + + + + +/**************** + * Solve the right side of the equation that defines a curve. + */ +static gcry_mpi_t +gen_y_2 (gcry_mpi_t x, elliptic_curve_t *base) +{ + gcry_mpi_t three, x_3, axb, y; + + three = mpi_alloc_set_ui (3); + x_3 = mpi_new (0); + axb = mpi_new (0); + y = mpi_new (0); + + mpi_powm (x_3, x, three, base->p); + mpi_mulm (axb, base->a, x, base->p); + mpi_addm (axb, axb, base->b, base->p); + mpi_addm (y, x_3, axb, base->p); + + mpi_free (x_3); + mpi_free (axb); + mpi_free (three); + return y; /* The quadratic value of the coordinate if it exist. */ +} + + + + + +/* Generate a random secret scalar k with an order of p + + At the beginning this was identical to the code is in elgamal.c. + Later imporved by mmr. Further simplified by wk. */ +static gcry_mpi_t +gen_k (gcry_mpi_t p, int security_level) +{ + gcry_mpi_t k; + unsigned int nbits; + + nbits = mpi_get_nbits (p); + k = mpi_snew (nbits); + if (DBG_CIPHER) + log_debug ("choosing a random k of %u bits\n", nbits); + + gcry_mpi_randomize (k, nbits, security_level); + + mpi_mod (k, k, p); /* k = k mod p */ + + return k; +} + +/**************** + * Generate the crypto system setup. + * As of now the fix NIST recommended values are used. + * The subgroup generator point is in another function: gen_big_point. + */ +static gpg_err_code_t +generate_curve (unsigned int nbits, const char *name, + elliptic_curve_t *curve, unsigned int *r_nbits) +{ + int idx, aliasno; + + if (name) + { + /* First check nor native curves. */ + for (idx = 0; domain_parms[idx].desc; idx++) + if (!strcmp (name, domain_parms[idx].desc)) + break; + /* If not found consult the alias table. */ + if (!domain_parms[idx].desc) + { + for (aliasno = 0; curve_aliases[aliasno].name; aliasno++) + if (!strcmp (name, curve_aliases[aliasno].other)) + break; + if (curve_aliases[aliasno].name) + { + for (idx = 0; domain_parms[idx].desc; idx++) + if (!strcmp (curve_aliases[aliasno].name, + domain_parms[idx].desc)) + break; + } + } + } + else + { + for (idx = 0; domain_parms[idx].desc; idx++) + if (nbits == domain_parms[idx].nbits) + break; + } + if (!domain_parms[idx].desc) + return GPG_ERR_INV_VALUE; + + /* In fips mode we only support NIST curves. Note that it is + possible to bypass this check by specifying the curve parameters + directly. */ + if (fips_mode () && !domain_parms[idx].fips ) + return GPG_ERR_NOT_SUPPORTED; + + + *r_nbits = domain_parms[idx].nbits; + curve->p = scanval (domain_parms[idx].p); + curve->a = scanval (domain_parms[idx].a); + curve->b = scanval (domain_parms[idx].b); + curve->n = scanval (domain_parms[idx].n); + curve->G.x = scanval (domain_parms[idx].g_x); + curve->G.y = scanval (domain_parms[idx].g_y); + curve->G.z = mpi_alloc_set_ui (1); + + return 0; +} + + +/* + * First obtain the setup. Over the finite field randomize an scalar + * secret value, and calculate the public point. + */ +static gpg_err_code_t +generate_key (ECC_secret_key *sk, unsigned int nbits, const char *name, + gcry_mpi_t g_x, gcry_mpi_t g_y, + gcry_mpi_t q_x, gcry_mpi_t q_y) +{ + gpg_err_code_t err; + elliptic_curve_t E; + gcry_mpi_t d; + mpi_point_t Q; + mpi_ec_t ctx; + + err = generate_curve (nbits, name, &E, &nbits); + if (err) + return err; + + if (DBG_CIPHER) + { + log_mpidump ("ecc generation p", E.p); + log_mpidump ("ecc generation a", E.a); + log_mpidump ("ecc generation b", E.b); + log_mpidump ("ecc generation n", E.n); + log_mpidump ("ecc generation Gx", E.G.x); + log_mpidump ("ecc generation Gy", E.G.y); + log_mpidump ("ecc generation Gz", E.G.z); + } + + if (DBG_CIPHER) + log_debug ("choosing a random x of size %u\n", nbits); + d = gen_k (E.n, GCRY_VERY_STRONG_RANDOM); + + /* Compute Q. */ + point_init (&Q); + ctx = _gcry_mpi_ec_init (E.p, E.a); + _gcry_mpi_ec_mul_point (&Q, d, &E.G, ctx); + + /* Copy the stuff to the key structures. */ + sk->E.p = mpi_copy (E.p); + sk->E.a = mpi_copy (E.a); + sk->E.b = mpi_copy (E.b); + point_init (&sk->E.G); + point_set (&sk->E.G, &E.G); + sk->E.n = mpi_copy (E.n); + point_init (&sk->Q); + point_set (&sk->Q, &Q); + sk->d = mpi_copy (d); + /* We also return copies of G and Q in affine coordinates if + requested. */ + if (g_x && g_y) + { + if (_gcry_mpi_ec_get_affine (g_x, g_y, &sk->E.G, ctx)) + log_fatal ("ecc generate: Failed to get affine coordinates\n"); + } + if (q_x && q_y) + { + if (_gcry_mpi_ec_get_affine (q_x, q_y, &sk->Q, ctx)) + log_fatal ("ecc generate: Failed to get affine coordinates\n"); + } + _gcry_mpi_ec_free (ctx); + + point_free (&Q); + mpi_free (d); + curve_free (&E); + + /* Now we can test our keys (this should never fail!). */ + test_keys (sk, nbits - 64); + + return 0; +} + + +/**************** + * To verify correct skey it use a random information. + * First, encrypt and decrypt this dummy value, + * test if the information is recuperated. + * Second, test with the sign and verify functions. + */ +static void +test_keys (ECC_secret_key *sk, unsigned int nbits) +{ + ECC_public_key pk; + gcry_mpi_t test = mpi_new (nbits); + mpi_point_t R_; + gcry_mpi_t c = mpi_new (nbits); + gcry_mpi_t out = mpi_new (nbits); + gcry_mpi_t r = mpi_new (nbits); + gcry_mpi_t s = mpi_new (nbits); + + if (DBG_CIPHER) + log_debug ("Testing key.\n"); + + point_init (&R_); + + pk.E = curve_copy (sk->E); + point_init (&pk.Q); + point_set (&pk.Q, &sk->Q); + + gcry_mpi_randomize (test, nbits, GCRY_WEAK_RANDOM); + + if (sign (test, sk, r, s) ) + log_fatal ("ECDSA operation: sign failed\n"); + + if (verify (test, &pk, r, s)) + { + log_fatal ("ECDSA operation: sign, verify failed\n"); + } + + if (DBG_CIPHER) + log_debug ("ECDSA operation: sign, verify ok.\n"); + + point_free (&pk.Q); + curve_free (&pk.E); + + point_free (&R_); + mpi_free (s); + mpi_free (r); + mpi_free (out); + mpi_free (c); + mpi_free (test); +} + +/**************** + * To check the validity of the value, recalculate the correspondence + * between the public value and the secret one. + */ +static int +check_secret_key (ECC_secret_key * sk) +{ + mpi_point_t Q; + gcry_mpi_t y_2, y2 = mpi_alloc (0); + mpi_ec_t ctx; + + /* ?primarity test of 'p' */ + /* (...) //!! */ + /* G in E(F_p) */ + y_2 = gen_y_2 (sk->E.G.x, &sk->E); /* y^2=x^3+a*x+b */ + mpi_mulm (y2, sk->E.G.y, sk->E.G.y, sk->E.p); /* y^2=y*y */ + if (mpi_cmp (y_2, y2)) + { + if (DBG_CIPHER) + log_debug ("Bad check: Point 'G' does not belong to curve 'E'!\n"); + return (1); + } + /* G != PaI */ + if (!mpi_cmp_ui (sk->E.G.z, 0)) + { + if (DBG_CIPHER) + log_debug ("Bad check: 'G' cannot be Point at Infinity!\n"); + return (1); + } + + point_init (&Q); + ctx = _gcry_mpi_ec_init (sk->E.p, sk->E.a); + _gcry_mpi_ec_mul_point (&Q, sk->E.n, &sk->E.G, ctx); + if (mpi_cmp_ui (Q.z, 0)) + { + if (DBG_CIPHER) + log_debug ("check_secret_key: E is not a curve of order n\n"); + point_free (&Q); + _gcry_mpi_ec_free (ctx); + return 1; + } + /* pubkey cannot be PaI */ + if (!mpi_cmp_ui (sk->Q.z, 0)) + { + if (DBG_CIPHER) + log_debug ("Bad check: Q can not be a Point at Infinity!\n"); + _gcry_mpi_ec_free (ctx); + return (1); + } + /* pubkey = [d]G over E */ + _gcry_mpi_ec_mul_point (&Q, sk->d, &sk->E.G, ctx); + if ((Q.x == sk->Q.x) && (Q.y == sk->Q.y) && (Q.z == sk->Q.z)) + { + if (DBG_CIPHER) + log_debug + ("Bad check: There is NO correspondence between 'd' and 'Q'!\n"); + _gcry_mpi_ec_free (ctx); + return (1); + } + _gcry_mpi_ec_free (ctx); + point_free (&Q); + return 0; +} + + +/* + * Return the signature struct (r,s) from the message hash. The caller + * must have allocated R and S. + */ +static gpg_err_code_t +sign (gcry_mpi_t input, ECC_secret_key *skey, gcry_mpi_t r, gcry_mpi_t s) +{ + gpg_err_code_t err = 0; + gcry_mpi_t k, dr, sum, k_1, x; + mpi_point_t I; + mpi_ec_t ctx; + + k = NULL; + dr = mpi_alloc (0); + sum = mpi_alloc (0); + k_1 = mpi_alloc (0); + x = mpi_alloc (0); + point_init (&I); + + mpi_set_ui (s, 0); + mpi_set_ui (r, 0); + + ctx = _gcry_mpi_ec_init (skey->E.p, skey->E.a); + + while (!mpi_cmp_ui (s, 0)) /* s == 0 */ + { + while (!mpi_cmp_ui (r, 0)) /* r == 0 */ + { + /* Note, that we are guaranteed to enter this loop at least + once because r has been intialized to 0. We can't use a + do_while because we want to keep the value of R even if S + has to be recomputed. */ + mpi_free (k); + k = gen_k (skey->E.n, GCRY_STRONG_RANDOM); + _gcry_mpi_ec_mul_point (&I, k, &skey->E.G, ctx); + if (_gcry_mpi_ec_get_affine (x, NULL, &I, ctx)) + { + if (DBG_CIPHER) + log_debug ("ecc sign: Failed to get affine coordinates\n"); + err = GPG_ERR_BAD_SIGNATURE; + goto leave; + } + mpi_mod (r, x, skey->E.n); /* r = x mod n */ + } + mpi_mulm (dr, skey->d, r, skey->E.n); /* dr = d*r mod n */ + mpi_addm (sum, input, dr, skey->E.n); /* sum = hash + (d*r) mod n */ + mpi_invm (k_1, k, skey->E.n); /* k_1 = k^(-1) mod n */ + mpi_mulm (s, k_1, sum, skey->E.n); /* s = k^(-1)*(hash+(d*r)) mod n */ + } + + leave: + _gcry_mpi_ec_free (ctx); + point_free (&I); + mpi_free (x); + mpi_free (k_1); + mpi_free (sum); + mpi_free (dr); + mpi_free (k); + + return err; +} + +/* + * Check if R and S verifies INPUT. + */ +static gpg_err_code_t +verify (gcry_mpi_t input, ECC_public_key *pkey, gcry_mpi_t r, gcry_mpi_t s) +{ + gpg_err_code_t err = 0; + gcry_mpi_t h, h1, h2, x, y; + mpi_point_t Q, Q1, Q2; + mpi_ec_t ctx; + + if( !(mpi_cmp_ui (r, 0) > 0 && mpi_cmp (r, pkey->E.n) < 0) ) + return GPG_ERR_BAD_SIGNATURE; /* Assertion 0 < r < n failed. */ + if( !(mpi_cmp_ui (s, 0) > 0 && mpi_cmp (s, pkey->E.n) < 0) ) + return GPG_ERR_BAD_SIGNATURE; /* Assertion 0 < s < n failed. */ + + h = mpi_alloc (0); + h1 = mpi_alloc (0); + h2 = mpi_alloc (0); + x = mpi_alloc (0); + y = mpi_alloc (0); + point_init (&Q); + point_init (&Q1); + point_init (&Q2); + + ctx = _gcry_mpi_ec_init (pkey->E.p, pkey->E.a); + + /* h = s^(-1) (mod n) */ + mpi_invm (h, s, pkey->E.n); +/* log_mpidump (" h", h); */ + /* h1 = hash * s^(-1) (mod n) */ + mpi_mulm (h1, input, h, pkey->E.n); +/* log_mpidump (" h1", h1); */ + /* Q1 = [ hash * s^(-1) ]G */ + _gcry_mpi_ec_mul_point (&Q1, h1, &pkey->E.G, ctx); +/* log_mpidump ("Q1.x", Q1.x); */ +/* log_mpidump ("Q1.y", Q1.y); */ +/* log_mpidump ("Q1.z", Q1.z); */ + /* h2 = r * s^(-1) (mod n) */ + mpi_mulm (h2, r, h, pkey->E.n); +/* log_mpidump (" h2", h2); */ + /* Q2 = [ r * s^(-1) ]Q */ + _gcry_mpi_ec_mul_point (&Q2, h2, &pkey->Q, ctx); +/* log_mpidump ("Q2.x", Q2.x); */ +/* log_mpidump ("Q2.y", Q2.y); */ +/* log_mpidump ("Q2.z", Q2.z); */ + /* Q = ([hash * s^(-1)]G) + ([r * s^(-1)]Q) */ + _gcry_mpi_ec_add_points (&Q, &Q1, &Q2, ctx); +/* log_mpidump (" Q.x", Q.x); */ +/* log_mpidump (" Q.y", Q.y); */ +/* log_mpidump (" Q.z", Q.z); */ + + if (!mpi_cmp_ui (Q.z, 0)) + { + if (DBG_CIPHER) + log_debug ("ecc verify: Rejected\n"); + err = GPG_ERR_BAD_SIGNATURE; + goto leave; + } + if (_gcry_mpi_ec_get_affine (x, y, &Q, ctx)) + { + if (DBG_CIPHER) + log_debug ("ecc verify: Failed to get affine coordinates\n"); + err = GPG_ERR_BAD_SIGNATURE; + goto leave; + } + mpi_mod (x, x, pkey->E.n); /* x = x mod E_n */ + if (mpi_cmp (x, r)) /* x != r */ + { + if (DBG_CIPHER) + { + log_mpidump (" x", x); + log_mpidump (" y", y); + log_mpidump (" r", r); + log_mpidump (" s", s); + log_debug ("ecc verify: Not verified\n"); + } + err = GPG_ERR_BAD_SIGNATURE; + goto leave; + } + if (DBG_CIPHER) + log_debug ("ecc verify: Accepted\n"); + + leave: + _gcry_mpi_ec_free (ctx); + point_free (&Q2); + point_free (&Q1); + point_free (&Q); + mpi_free (y); + mpi_free (x); + mpi_free (h2); + mpi_free (h1); + mpi_free (h); + return err; +} + + + +/********************************************* + ************** interface ****************** + *********************************************/ +static gcry_mpi_t +ec2os (gcry_mpi_t x, gcry_mpi_t y, gcry_mpi_t p) +{ + gpg_error_t err; + int pbytes = (mpi_get_nbits (p)+7)/8; + size_t n; + unsigned char *buf, *ptr; + gcry_mpi_t result; + + buf = gcry_xmalloc ( 1 + 2*pbytes ); + *buf = 04; /* Uncompressed point. */ + ptr = buf+1; + err = gcry_mpi_print (GCRYMPI_FMT_USG, ptr, pbytes, &n, x); + if (err) + log_fatal ("mpi_print failed: %s\n", gpg_strerror (err)); + if (n < pbytes) + { + memmove (ptr+(pbytes-n), ptr, n); + memset (ptr, 0, (pbytes-n)); + } + ptr += pbytes; + err = gcry_mpi_print (GCRYMPI_FMT_USG, ptr, pbytes, &n, y); + if (err) + log_fatal ("mpi_print failed: %s\n", gpg_strerror (err)); + if (n < pbytes) + { + memmove (ptr+(pbytes-n), ptr, n); + memset (ptr, 0, (pbytes-n)); + } + + err = gcry_mpi_scan (&result, GCRYMPI_FMT_USG, buf, 1+2*pbytes, NULL); + if (err) + log_fatal ("mpi_scan failed: %s\n", gpg_strerror (err)); + gcry_free (buf); + + mpi_free (x); + mpi_free (y); + + return result; +} + +/* RESULT must have been initialized and is set on success to the + point given by VALUE. */ +static gcry_error_t +os2ec (mpi_point_t *result, gcry_mpi_t value) +{ + gcry_error_t err; + size_t n; + unsigned char *buf; + gcry_mpi_t x, y; + + n = (mpi_get_nbits (value)+7)/8; + buf = gcry_xmalloc (n); + err = gcry_mpi_print (GCRYMPI_FMT_USG, buf, n, &n, value); + if (err) + { + gcry_free (buf); + return err; + } + if (n < 1) + { + gcry_free (buf); + return GPG_ERR_INV_OBJ; + } + if (*buf != 4) + { + gcry_free (buf); + return GPG_ERR_NOT_IMPLEMENTED; /* No support for point compression. */ + } + if ( ((n-1)%2) ) + { + gcry_free (buf); + return GPG_ERR_INV_OBJ; + } + n = (n-1)/2; + err = gcry_mpi_scan (&x, GCRYMPI_FMT_USG, buf+1, n, NULL); + if (err) + { + gcry_free (buf); + return err; + } + err = gcry_mpi_scan (&y, GCRYMPI_FMT_USG, buf+1+n, n, NULL); + gcry_free (buf); + if (err) + { + mpi_free (x); + return err; + } + + mpi_set (result->x, x); + mpi_set (result->y, y); + mpi_set_ui (result->z, 1); + + mpi_free (x); + mpi_free (y); + + return 0; +} + + +/* Extended version of ecc_generate. */ +static gcry_err_code_t +ecc_generate_ext (int algo, unsigned int nbits, unsigned long evalue, + const gcry_sexp_t genparms, + gcry_mpi_t *skey, gcry_mpi_t **retfactors, + gcry_sexp_t *r_extrainfo) +{ + gpg_err_code_t ec; + ECC_secret_key sk; + gcry_mpi_t g_x, g_y, q_x, q_y; + char *curve_name = NULL; + gcry_sexp_t l1; + + (void)algo; + (void)evalue; + (void)r_extrainfo; + + if (genparms) + { + /* Parse the optional "curve" parameter. */ + l1 = gcry_sexp_find_token (genparms, "curve", 0); + if (l1) + { + curve_name = _gcry_sexp_nth_string (l1, 1); + gcry_sexp_release (l1); + if (!curve_name) + return GPG_ERR_INV_OBJ; /* No curve name or value too large. */ + } + } + + /* NBITS is required if no curve name has been given. */ + if (!nbits && !curve_name) + return GPG_ERR_NO_OBJ; /* No NBITS parameter. */ + + g_x = mpi_new (0); + g_y = mpi_new (0); + q_x = mpi_new (0); + q_y = mpi_new (0); + ec = generate_key (&sk, nbits, curve_name, g_x, g_y, q_x, q_y); + gcry_free (curve_name); + if (ec) + return ec; + + skey[0] = sk.E.p; + skey[1] = sk.E.a; + skey[2] = sk.E.b; + /* The function ec2os releases g_x and g_y. */ + skey[3] = ec2os (g_x, g_y, sk.E.p); + skey[4] = sk.E.n; + /* The function ec2os releases g_x and g_y. */ + skey[5] = ec2os (q_x, q_y, sk.E.p); + skey[6] = sk.d; + + point_free (&sk.E.G); + point_free (&sk.Q); + + /* Make an empty list of factors. */ + *retfactors = gcry_calloc ( 1, sizeof **retfactors ); + if (!*retfactors) + return gpg_err_code_from_syserror (); + + return 0; +} + + +static gcry_err_code_t +ecc_generate (int algo, unsigned int nbits, unsigned long evalue, + gcry_mpi_t *skey, gcry_mpi_t **retfactors) +{ + (void)evalue; + return ecc_generate_ext (algo, nbits, 0, NULL, skey, retfactors, NULL); +} + + +/* Return the parameters of the curve NAME. */ +static gcry_err_code_t +ecc_get_param (const char *name, gcry_mpi_t *pkey) +{ + gpg_err_code_t err; + unsigned int nbits; + elliptic_curve_t E; + mpi_ec_t ctx; + gcry_mpi_t g_x, g_y; + + err = generate_curve (0, name, &E, &nbits); + if (err) + return err; + + g_x = mpi_new (0); + g_y = mpi_new (0); + ctx = _gcry_mpi_ec_init (E.p, E.a); + if (_gcry_mpi_ec_get_affine (g_x, g_y, &E.G, ctx)) + log_fatal ("ecc get param: Failed to get affine coordinates\n"); + _gcry_mpi_ec_free (ctx); + point_free (&E.G); + + pkey[0] = E.p; + pkey[1] = E.a; + pkey[2] = E.b; + pkey[3] = ec2os (g_x, g_y, E.p); + pkey[4] = E.n; + pkey[5] = NULL; + + return 0; +} + + +static gcry_err_code_t +ecc_check_secret_key (int algo, gcry_mpi_t *skey) +{ + gpg_err_code_t err; + ECC_secret_key sk; + + (void)algo; + + if (!skey[0] || !skey[1] || !skey[2] || !skey[3] || !skey[4] || !skey[5] + || !skey[6] || !skey[7] || !skey[8] || !skey[9] || !skey[10]) + return GPG_ERR_BAD_MPI; + + sk.E.p = skey[0]; + sk.E.a = skey[1]; + sk.E.b = skey[2]; + point_init (&sk.E.G); + err = os2ec (&sk.E.G, skey[3]); + if (err) + { + point_free (&sk.E.G); + return err; + } + sk.E.n = skey[4]; + point_init (&sk.Q); + err = os2ec (&sk.Q, skey[5]); + if (err) + { + point_free (&sk.E.G); + point_free (&sk.Q); + return err; + } + + sk.d = skey[6]; + + if (check_secret_key (&sk)) + { + point_free (&sk.E.G); + point_free (&sk.Q); + return GPG_ERR_BAD_SECKEY; + } + point_free (&sk.E.G); + point_free (&sk.Q); + return 0; +} + + +static gcry_err_code_t +ecc_sign (int algo, gcry_mpi_t *resarr, gcry_mpi_t data, gcry_mpi_t *skey) +{ + gpg_err_code_t err; + ECC_secret_key sk; + + (void)algo; + + if (!data || !skey[0] || !skey[1] || !skey[2] || !skey[3] || !skey[4] + || !skey[5] || !skey[6] ) + return GPG_ERR_BAD_MPI; + + sk.E.p = skey[0]; + sk.E.a = skey[1]; + sk.E.b = skey[2]; + point_init (&sk.E.G); + err = os2ec (&sk.E.G, skey[3]); + if (err) + { + point_free (&sk.E.G); + return err; + } + sk.E.n = skey[4]; + point_init (&sk.Q); + err = os2ec (&sk.Q, skey[5]); + if (err) + { + point_free (&sk.E.G); + point_free (&sk.Q); + return err; + } + sk.d = skey[6]; + + resarr[0] = mpi_alloc (mpi_get_nlimbs (sk.E.p)); + resarr[1] = mpi_alloc (mpi_get_nlimbs (sk.E.p)); + err = sign (data, &sk, resarr[0], resarr[1]); + if (err) + { + mpi_free (resarr[0]); + mpi_free (resarr[1]); + resarr[0] = NULL; /* Mark array as released. */ + } + point_free (&sk.E.G); + point_free (&sk.Q); + return err; +} + +static gcry_err_code_t +ecc_verify (int algo, gcry_mpi_t hash, gcry_mpi_t *data, gcry_mpi_t *pkey, + int (*cmp)(void *, gcry_mpi_t), void *opaquev) +{ + gpg_err_code_t err; + ECC_public_key pk; + + (void)algo; + (void)cmp; + (void)opaquev; + + if (!data[0] || !data[1] || !hash || !pkey[0] || !pkey[1] || !pkey[2] + || !pkey[3] || !pkey[4] || !pkey[5] ) + return GPG_ERR_BAD_MPI; + + pk.E.p = pkey[0]; + pk.E.a = pkey[1]; + pk.E.b = pkey[2]; + point_init (&pk.E.G); + err = os2ec (&pk.E.G, pkey[3]); + if (err) + { + point_free (&pk.E.G); + return err; + } + pk.E.n = pkey[4]; + point_init (&pk.Q); + err = os2ec (&pk.Q, pkey[5]); + if (err) + { + point_free (&pk.E.G); + point_free (&pk.Q); + return err; + } + + err = verify (hash, &pk, data[0], data[1]); + + point_free (&pk.E.G); + point_free (&pk.Q); + return err; +} + + + +static unsigned int +ecc_get_nbits (int algo, gcry_mpi_t *pkey) +{ + (void)algo; + + return mpi_get_nbits (pkey[0]); +} + + + +/* See rsa.c for a description of this function. */ +static gpg_err_code_t +compute_keygrip (gcry_md_hd_t md, gcry_sexp_t keyparam) +{ + static const char names[] = "pabgnq"; + gpg_err_code_t ec = 0; + gcry_sexp_t l1; + gcry_mpi_t values[6]; + int idx; + + /* Clear the values for easier error cleanup. */ + for (idx=0; idx < 6; idx++) + values[idx] = NULL; + + /* Fill values with all available parameters. */ + for (idx=0; idx < 6; idx++) + { + l1 = gcry_sexp_find_token (keyparam, names+idx, 1); + if (l1) + { + values[idx] = gcry_sexp_nth_mpi (l1, 1, GCRYMPI_FMT_USG); + gcry_sexp_release (l1); + if (!values[idx]) + { + ec = GPG_ERR_INV_OBJ; + goto leave; + } + } + } + + /* Check whether a curve parameter is available and use that to fill + in missing values. */ + l1 = gcry_sexp_find_token (keyparam, "curve", 5); + if (l1) + { + char *curve; + gcry_mpi_t tmpvalues[6]; + + for (idx = 0; idx < 6; idx++) + tmpvalues[idx] = NULL; + + curve = _gcry_sexp_nth_string (l1, 1); + if (!curve) + { + ec = GPG_ERR_INV_OBJ; /* Name missing or out of core. */ + goto leave; + } + ec = ecc_get_param (curve, tmpvalues); + gcry_free (curve); + if (ec) + goto leave; + + for (idx = 0; idx < 6; idx++) + { + if (!values[idx]) + values[idx] = tmpvalues[idx]; + else + mpi_free (tmpvalues[idx]); + } + } + + /* Check that all parameters are known and normalize all MPIs (that + should not be required but we use an internal fucntion later and + thus we better make 100% sure that they are normalized). */ + for (idx = 0; idx < 6; idx++) + if (!values[idx]) + { + ec = GPG_ERR_NO_OBJ; + goto leave; + } + else + _gcry_mpi_normalize (values[idx]); + + /* Hash them all. */ + for (idx = 0; idx < 6; idx++) + { + char buf[30]; + unsigned char *rawmpi; + unsigned int rawmpilen; + + rawmpi = _gcry_mpi_get_buffer (values[idx], &rawmpilen, NULL); + if (!rawmpi) + { + ec = gpg_err_code_from_syserror (); + goto leave; + } + snprintf (buf, sizeof buf, "(1:%c%u:", names[idx], rawmpilen); + gcry_md_write (md, buf, strlen (buf)); + gcry_md_write (md, rawmpi, rawmpilen); + gcry_md_write (md, ")", 1); + gcry_free (rawmpi); + } + + leave: + for (idx = 0; idx < 6; idx++) + _gcry_mpi_release (values[idx]); + + return ec; +} + + + + + +/* + Self-test section. + */ + + +static gpg_err_code_t +selftests_ecdsa (selftest_report_func_t report) +{ + const char *what; + const char *errtxt; + + what = "low-level"; + errtxt = NULL; /*selftest ();*/ + if (errtxt) + goto failed; + + /* FIXME: need more tests. */ + + return 0; /* Succeeded. */ + + failed: + if (report) + report ("pubkey", GCRY_PK_ECDSA, what, errtxt); + return GPG_ERR_SELFTEST_FAILED; +} + + +/* Run a full self-test for ALGO and return 0 on success. */ +static gpg_err_code_t +run_selftests (int algo, int extended, selftest_report_func_t report) +{ + gpg_err_code_t ec; + + (void)extended; + + switch (algo) + { + case GCRY_PK_ECDSA: + ec = selftests_ecdsa (report); + break; + default: + ec = GPG_ERR_PUBKEY_ALGO; + break; + + } + return ec; +} + + + + +static const char *ecdsa_names[] = + { + "ecdsa", + "ecc", + NULL, + }; + +gcry_pk_spec_t _gcry_pubkey_spec_ecdsa = + { + "ECDSA", ecdsa_names, + "pabgnq", "pabgnqd", "", "rs", "pabgnq", + GCRY_PK_USAGE_SIGN, + ecc_generate, + ecc_check_secret_key, + NULL, + NULL, + ecc_sign, + ecc_verify, + ecc_get_nbits + }; + +pk_extra_spec_t _gcry_pubkey_extraspec_ecdsa = + { + run_selftests, + ecc_generate_ext, + compute_keygrip, + ecc_get_param + }; + |