/*
This file is part of GNUnet.
Copyright (C) 2012, 2013, 2015 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.
GNUnet 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
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see .
SPDX-License-Identifier: AGPL3.0-or-later
*/
/**
* @file util/crypto_ecc.c
* @brief public key cryptography (ECC) with libgcrypt
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include "gnunet_crypto_lib.h"
#include "gnunet_strings_lib.h"
#include "benchmark.h"
#define EXTRA_CHECKS 0
/**
* Name of the curve we are using. Note that we have hard-coded
* structs that use 256 bits, so using a bigger curve will require
* changes that break stuff badly. The name of the curve given here
* must be agreed by all peers and be supported by libgcrypt.
*/
#define CURVE "Ed25519"
#define LOG(kind,...) GNUNET_log_from (kind, "util-crypto-ecc", __VA_ARGS__)
#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-crypto-ecc", syscall)
#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util-crypto-ecc", syscall, filename)
/**
* Log an error message at log-level 'level' that indicates
* a failure of the command 'cmd' with the message given
* by gcry_strerror(rc).
*/
#define LOG_GCRY(level, cmd, rc) do { LOG(level, _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0)
/**
* Extract values from an S-expression.
*
* @param array where to store the result(s)
* @param sexp S-expression to parse
* @param topname top-level name in the S-expression that is of interest
* @param elems names of the elements to extract
* @return 0 on success
*/
static int
key_from_sexp (gcry_mpi_t * array,
gcry_sexp_t sexp,
const char *topname,
const char *elems)
{
gcry_sexp_t list;
gcry_sexp_t l2;
const char *s;
unsigned int i;
unsigned int idx;
list = gcry_sexp_find_token (sexp, topname, 0);
if (! list)
return 1;
l2 = gcry_sexp_cadr (list);
gcry_sexp_release (list);
list = l2;
if (! list)
return 2;
idx = 0;
for (s = elems; *s; s++, idx++)
{
l2 = gcry_sexp_find_token (list, s, 1);
if (! l2)
{
for (i = 0; i < idx; i++)
{
gcry_free (array[i]);
array[i] = NULL;
}
gcry_sexp_release (list);
return 3; /* required parameter not found */
}
array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
gcry_sexp_release (l2);
if (! array[idx])
{
for (i = 0; i < idx; i++)
{
gcry_free (array[i]);
array[i] = NULL;
}
gcry_sexp_release (list);
return 4; /* required parameter is invalid */
}
}
gcry_sexp_release (list);
return 0;
}
/**
* Convert the given private key from the network format to the
* S-expression that can be used by libgcrypt.
*
* @param priv private key to decode
* @return NULL on error
*/
static gcry_sexp_t
decode_private_ecdsa_key (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv)
{
gcry_sexp_t result;
int rc;
rc = gcry_sexp_build (&result, NULL,
"(private-key(ecc(curve \"" CURVE "\")"
"(d %b)))",
(int) sizeof (priv->d), priv->d);
if (0 != rc)
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
GNUNET_assert (0);
}
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (result)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
GNUNET_assert (0);
}
#endif
return result;
}
/**
* Convert the given private key from the network format to the
* S-expression that can be used by libgcrypt.
*
* @param priv private key to decode
* @return NULL on error
*/
static gcry_sexp_t
decode_private_eddsa_key (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv)
{
gcry_sexp_t result;
int rc;
rc = gcry_sexp_build (&result, NULL,
"(private-key(ecc(curve \"" CURVE "\")"
"(flags eddsa)(d %b)))",
(int)sizeof (priv->d), priv->d);
if (0 != rc)
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
GNUNET_assert (0);
}
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (result)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
GNUNET_assert (0);
}
#endif
return result;
}
/**
* Convert the given private key from the network format to the
* S-expression that can be used by libgcrypt.
*
* @param priv private key to decode
* @return NULL on error
*/
static gcry_sexp_t
decode_private_ecdhe_key (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv)
{
gcry_sexp_t result;
int rc;
rc = gcry_sexp_build (&result, NULL,
"(private-key(ecc(curve \"" CURVE "\")"
"(d %b)))",
(int)sizeof (priv->d), priv->d);
if (0 != rc)
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
GNUNET_assert (0);
}
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (result)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
GNUNET_assert (0);
}
#endif
return result;
}
/**
* Extract the public key for the given private key.
*
* @param priv the private key
* @param pub where to write the public key
*/
void
GNUNET_CRYPTO_ecdsa_key_get_public (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv,
struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
{
gcry_sexp_t sexp;
gcry_ctx_t ctx;
gcry_mpi_t q;
BENCHMARK_START (ecdsa_key_get_public);
sexp = decode_private_ecdsa_key (priv);
GNUNET_assert (NULL != sexp);
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, sexp, NULL));
gcry_sexp_release (sexp);
q = gcry_mpi_ec_get_mpi ("q@eddsa", ctx, 0);
GNUNET_assert (NULL != q);
GNUNET_CRYPTO_mpi_print_unsigned (pub->q_y, sizeof (pub->q_y), q);
gcry_mpi_release (q);
gcry_ctx_release (ctx);
BENCHMARK_END (ecdsa_key_get_public);
}
/**
* Extract the public key for the given private key.
*
* @param priv the private key
* @param pub where to write the public key
*/
void
GNUNET_CRYPTO_eddsa_key_get_public (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv,
struct GNUNET_CRYPTO_EddsaPublicKey *pub)
{
gcry_sexp_t sexp;
gcry_ctx_t ctx;
gcry_mpi_t q;
BENCHMARK_START (eddsa_key_get_public);
sexp = decode_private_eddsa_key (priv);
GNUNET_assert (NULL != sexp);
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, sexp, NULL));
gcry_sexp_release (sexp);
q = gcry_mpi_ec_get_mpi ("q@eddsa", ctx, 0);
GNUNET_assert (q);
GNUNET_CRYPTO_mpi_print_unsigned (pub->q_y, sizeof (pub->q_y), q);
gcry_mpi_release (q);
gcry_ctx_release (ctx);
BENCHMARK_END (eddsa_key_get_public);
}
/**
* Extract the public key for the given private key.
*
* @param priv the private key
* @param pub where to write the public key
*/
void
GNUNET_CRYPTO_ecdhe_key_get_public (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
struct GNUNET_CRYPTO_EcdhePublicKey *pub)
{
gcry_sexp_t sexp;
gcry_ctx_t ctx;
gcry_mpi_t q;
BENCHMARK_START (ecdhe_key_get_public);
sexp = decode_private_ecdhe_key (priv);
GNUNET_assert (NULL != sexp);
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, sexp, NULL));
gcry_sexp_release (sexp);
q = gcry_mpi_ec_get_mpi ("q@eddsa", ctx, 0);
GNUNET_assert (q);
GNUNET_CRYPTO_mpi_print_unsigned (pub->q_y, sizeof (pub->q_y), q);
gcry_mpi_release (q);
gcry_ctx_release (ctx);
BENCHMARK_END (ecdhe_key_get_public);
}
/**
* Convert a public key to a string.
*
* @param pub key to convert
* @return string representing @a pub
*/
char *
GNUNET_CRYPTO_ecdsa_public_key_to_string (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
{
char *pubkeybuf;
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)) * 8;
char *end;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
pubkeybuf = GNUNET_malloc (keylen + 1);
end = GNUNET_STRINGS_data_to_string ((unsigned char *) pub,
sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
pubkeybuf,
keylen);
if (NULL == end)
{
GNUNET_free (pubkeybuf);
return NULL;
}
*end = '\0';
return pubkeybuf;
}
/**
* Convert a public key to a string.
*
* @param pub key to convert
* @return string representing @a pub
*/
char *
GNUNET_CRYPTO_eddsa_public_key_to_string (const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
{
char *pubkeybuf;
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EddsaPublicKey)) * 8;
char *end;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
pubkeybuf = GNUNET_malloc (keylen + 1);
end = GNUNET_STRINGS_data_to_string ((unsigned char *) pub,
sizeof (struct GNUNET_CRYPTO_EddsaPublicKey),
pubkeybuf,
keylen);
if (NULL == end)
{
GNUNET_free (pubkeybuf);
return NULL;
}
*end = '\0';
return pubkeybuf;
}
/**
* Convert a private key to a string.
*
* @param priv key to convert
* @return string representing @a pub
*/
char *
GNUNET_CRYPTO_eddsa_private_key_to_string (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv)
{
char *privkeybuf;
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EddsaPrivateKey)) * 8;
char *end;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
privkeybuf = GNUNET_malloc (keylen + 1);
end = GNUNET_STRINGS_data_to_string ((unsigned char *) priv,
sizeof (struct GNUNET_CRYPTO_EddsaPrivateKey),
privkeybuf,
keylen);
if (NULL == end)
{
GNUNET_free (privkeybuf);
return NULL;
}
*end = '\0';
return privkeybuf;
}
/**
* Convert a string representing a public key to a public key.
*
* @param enc encoded public key
* @param enclen number of bytes in @a enc (without 0-terminator)
* @param pub where to store the public key
* @return #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecdsa_public_key_from_string (const char *enc,
size_t enclen,
struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
{
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)) * 8;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
if (enclen != keylen)
return GNUNET_SYSERR;
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (enc, enclen,
pub,
sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)))
return GNUNET_SYSERR;
return GNUNET_OK;
}
/**
* Convert a string representing a public key to a public key.
*
* @param enc encoded public key
* @param enclen number of bytes in @a enc (without 0-terminator)
* @param pub where to store the public key
* @return #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_eddsa_public_key_from_string (const char *enc,
size_t enclen,
struct GNUNET_CRYPTO_EddsaPublicKey *pub)
{
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EddsaPublicKey)) * 8;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
if (enclen != keylen)
return GNUNET_SYSERR;
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (enc, enclen,
pub,
sizeof (struct GNUNET_CRYPTO_EddsaPublicKey)))
return GNUNET_SYSERR;
return GNUNET_OK;
}
/**
* Convert a string representing a private key to a private key.
*
* @param enc encoded public key
* @param enclen number of bytes in @a enc (without 0-terminator)
* @param priv where to store the private key
* @return #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_eddsa_private_key_from_string (const char *enc,
size_t enclen,
struct GNUNET_CRYPTO_EddsaPrivateKey *priv)
{
size_t keylen = (sizeof (struct GNUNET_CRYPTO_EddsaPrivateKey)) * 8;
if (keylen % 5 > 0)
keylen += 5 - keylen % 5;
keylen /= 5;
if (enclen != keylen)
return GNUNET_SYSERR;
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (enc, enclen,
priv,
sizeof (struct GNUNET_CRYPTO_EddsaPrivateKey)))
return GNUNET_SYSERR;
#if CRYPTO_BUG
if (GNUNET_OK !=
check_eddsa_key (priv))
{
GNUNET_break (0);
return GNUNET_OK;
}
#endif
return GNUNET_OK;
}
/**
* @ingroup crypto
* Clear memory that was used to store a private key.
*
* @param pk location of the key
*/
void
GNUNET_CRYPTO_ecdhe_key_clear (struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
{
memset (pk, 0, sizeof (struct GNUNET_CRYPTO_EcdhePrivateKey));
}
/**
* @ingroup crypto
* Clear memory that was used to store a private key.
*
* @param pk location of the key
*/
void
GNUNET_CRYPTO_ecdsa_key_clear (struct GNUNET_CRYPTO_EcdsaPrivateKey *pk)
{
memset (pk, 0, sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey));
}
/**
* @ingroup crypto
* Clear memory that was used to store a private key.
*
* @param pk location of the key
*/
void
GNUNET_CRYPTO_eddsa_key_clear (struct GNUNET_CRYPTO_EddsaPrivateKey *pk)
{
memset (pk, 0, sizeof (struct GNUNET_CRYPTO_EddsaPrivateKey));
}
/**
* Create a new private key. Caller must free return value.
*
* @return fresh private key
*/
struct GNUNET_CRYPTO_EcdhePrivateKey *
GNUNET_CRYPTO_ecdhe_key_create ()
{
struct GNUNET_CRYPTO_EcdhePrivateKey *priv;
priv = GNUNET_new (struct GNUNET_CRYPTO_EcdhePrivateKey);
if (GNUNET_OK !=
GNUNET_CRYPTO_ecdhe_key_create2 (priv))
{
GNUNET_free (priv);
return NULL;
}
return priv;
}
/**
* @ingroup crypto
* Create a new private key. Clear with #GNUNET_CRYPTO_ecdhe_key_clear().
*
* @param[out] pk set to fresh private key;
* @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
*/
int
GNUNET_CRYPTO_ecdhe_key_create2 (struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
{
gcry_sexp_t priv_sexp;
gcry_sexp_t s_keyparam;
gcry_mpi_t d;
int rc;
BENCHMARK_START (ecdhe_key_create);
/* NOTE: For libgcrypt >= 1.7, we do not need the 'eddsa' flag here,
but should also be harmless. For libgcrypt < 1.7, using 'eddsa'
disables an expensive key testing routine. We do not want to run
the expensive check for ECDHE, as we generate TONS of keys to
use for a very short time. */
if (0 != (rc = gcry_sexp_build (&s_keyparam, NULL,
"(genkey(ecc(curve \"" CURVE "\")"
"(flags eddsa no-keytest)))")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
return GNUNET_SYSERR;
}
if (0 != (rc = gcry_pk_genkey (&priv_sexp, s_keyparam)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_genkey", rc);
gcry_sexp_release (s_keyparam);
return GNUNET_SYSERR;
}
gcry_sexp_release (s_keyparam);
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (priv_sexp)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
gcry_sexp_release (priv_sexp);
return GNUNET_SYSERR;
}
#endif
if (0 != (rc = key_from_sexp (&d, priv_sexp, "private-key", "d")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "key_from_sexp", rc);
gcry_sexp_release (priv_sexp);
return GNUNET_SYSERR;
}
gcry_sexp_release (priv_sexp);
GNUNET_CRYPTO_mpi_print_unsigned (pk->d, sizeof (pk->d), d);
gcry_mpi_release (d);
BENCHMARK_END (ecdhe_key_create);
return GNUNET_OK;
}
/**
* Create a new private key. Caller must free return value.
*
* @return fresh private key
*/
struct GNUNET_CRYPTO_EcdsaPrivateKey *
GNUNET_CRYPTO_ecdsa_key_create ()
{
struct GNUNET_CRYPTO_EcdsaPrivateKey *priv;
gcry_sexp_t priv_sexp;
gcry_sexp_t s_keyparam;
gcry_mpi_t d;
int rc;
BENCHMARK_START (ecdsa_key_create);
if (0 != (rc = gcry_sexp_build (&s_keyparam, NULL,
"(genkey(ecc(curve \"" CURVE "\")"
"(flags)))")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
return NULL;
}
if (0 != (rc = gcry_pk_genkey (&priv_sexp, s_keyparam)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_genkey", rc);
gcry_sexp_release (s_keyparam);
return NULL;
}
gcry_sexp_release (s_keyparam);
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (priv_sexp)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
gcry_sexp_release (priv_sexp);
return NULL;
}
#endif
if (0 != (rc = key_from_sexp (&d, priv_sexp, "private-key", "d")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "key_from_sexp", rc);
gcry_sexp_release (priv_sexp);
return NULL;
}
gcry_sexp_release (priv_sexp);
priv = GNUNET_new (struct GNUNET_CRYPTO_EcdsaPrivateKey);
GNUNET_CRYPTO_mpi_print_unsigned (priv->d, sizeof (priv->d), d);
gcry_mpi_release (d);
BENCHMARK_END (ecdsa_key_create);
return priv;
}
/**
* Create a new private key. Caller must free return value.
*
* @return fresh private key
*/
struct GNUNET_CRYPTO_EddsaPrivateKey *
GNUNET_CRYPTO_eddsa_key_create ()
{
struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
gcry_sexp_t priv_sexp;
gcry_sexp_t s_keyparam;
gcry_mpi_t d;
int rc;
BENCHMARK_START (eddsa_key_create);
#if CRYPTO_BUG
again:
#endif
if (0 != (rc = gcry_sexp_build (&s_keyparam, NULL,
"(genkey(ecc(curve \"" CURVE "\")"
"(flags eddsa)))")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
return NULL;
}
if (0 != (rc = gcry_pk_genkey (&priv_sexp, s_keyparam)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_genkey", rc);
gcry_sexp_release (s_keyparam);
return NULL;
}
gcry_sexp_release (s_keyparam);
#if EXTRA_CHECKS
if (0 != (rc = gcry_pk_testkey (priv_sexp)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
gcry_sexp_release (priv_sexp);
return NULL;
}
#endif
if (0 != (rc = key_from_sexp (&d, priv_sexp, "private-key", "d")))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "key_from_sexp", rc);
gcry_sexp_release (priv_sexp);
return NULL;
}
gcry_sexp_release (priv_sexp);
priv = GNUNET_new (struct GNUNET_CRYPTO_EddsaPrivateKey);
GNUNET_CRYPTO_mpi_print_unsigned (priv->d, sizeof (priv->d), d);
gcry_mpi_release (d);
#if CRYPTO_BUG
if (GNUNET_OK !=
check_eddsa_key (priv))
{
GNUNET_break (0);
GNUNET_free (priv);
goto again;
}
#endif
BENCHMARK_END (eddsa_key_create);
return priv;
}
/**
* Get the shared private key we use for anonymous users.
*
* @return "anonymous" private key
*/
const struct GNUNET_CRYPTO_EcdsaPrivateKey *
GNUNET_CRYPTO_ecdsa_key_get_anonymous ()
{
/**
* 'anonymous' pseudonym (global static, d=1, public key = G
* (generator).
*/
static struct GNUNET_CRYPTO_EcdsaPrivateKey anonymous;
static int once;
if (once)
return &anonymous;
GNUNET_CRYPTO_mpi_print_unsigned (anonymous.d,
sizeof (anonymous.d),
GCRYMPI_CONST_ONE);
once = 1;
return &anonymous;
}
/**
* Convert the data specified in the given purpose argument to an
* S-expression suitable for signature operations.
*
* @param purpose data to convert
* @return converted s-expression
*/
static gcry_sexp_t
data_to_eddsa_value (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose)
{
gcry_sexp_t data;
int rc;
/* SEE #5398 */
#if 1
struct GNUNET_HashCode hc;
GNUNET_CRYPTO_hash (purpose,
ntohl (purpose->size),
&hc);
if (0 != (rc = gcry_sexp_build (&data, NULL,
"(data(flags eddsa)(hash-algo %s)(value %b))",
"sha512",
(int)sizeof (hc),
&hc)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_sexp_build",
rc);
return NULL;
}
#else
GNUNET_CRYPTO_hash (purpose, ntohl (purpose->size), &hc);
if (0 != (rc = gcry_sexp_build (&data, NULL,
"(data(flags eddsa)(hash-algo %s)(value %b))",
"sha512",
ntohl (purpose->size),
purpose)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_sexp_build",
rc);
return NULL;
}
#endif
return data;
}
/**
* Convert the data specified in the given purpose argument to an
* S-expression suitable for signature operations.
*
* @param purpose data to convert
* @return converted s-expression
*/
static gcry_sexp_t
data_to_ecdsa_value (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose)
{
gcry_sexp_t data;
int rc;
/* See #5398 */
#if 1
struct GNUNET_HashCode hc;
GNUNET_CRYPTO_hash (purpose,
ntohl (purpose->size),
&hc);
if (0 != (rc = gcry_sexp_build (&data, NULL,
"(data(flags rfc6979)(hash %s %b))",
"sha512",
(int)sizeof (hc), &hc)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_sexp_build",
rc);
return NULL;
}
#else
if (0 != (rc = gcry_sexp_build (&data, NULL,
"(data(flags rfc6979)(hash %s %b))",
"sha512",
ntohl (purpose->size),
purpose)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR,
"gcry_sexp_build",
rc);
return NULL;
}
#endif
return data;
}
/**
* Sign a given block.
*
* @param priv private key to use for the signing
* @param purpose what to sign (size, purpose)
* @param sig where to write the signature
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecdsa_sign (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv,
const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
struct GNUNET_CRYPTO_EcdsaSignature *sig)
{
gcry_sexp_t priv_sexp;
gcry_sexp_t sig_sexp;
gcry_sexp_t data;
int rc;
gcry_mpi_t rs[2];
BENCHMARK_START (ecdsa_sign);
priv_sexp = decode_private_ecdsa_key (priv);
data = data_to_ecdsa_value (purpose);
if (0 != (rc = gcry_pk_sign (&sig_sexp, data, priv_sexp)))
{
LOG (GNUNET_ERROR_TYPE_WARNING,
_("ECC signing failed at %s:%d: %s\n"), __FILE__,
__LINE__, gcry_strerror (rc));
gcry_sexp_release (data);
gcry_sexp_release (priv_sexp);
return GNUNET_SYSERR;
}
gcry_sexp_release (priv_sexp);
gcry_sexp_release (data);
/* extract 'r' and 's' values from sexpression 'sig_sexp' and store in
'signature' */
if (0 != (rc = key_from_sexp (rs, sig_sexp, "sig-val", "rs")))
{
GNUNET_break (0);
gcry_sexp_release (sig_sexp);
return GNUNET_SYSERR;
}
gcry_sexp_release (sig_sexp);
GNUNET_CRYPTO_mpi_print_unsigned (sig->r,
sizeof (sig->r),
rs[0]);
GNUNET_CRYPTO_mpi_print_unsigned (sig->s,
sizeof (sig->s),
rs[1]);
gcry_mpi_release (rs[0]);
gcry_mpi_release (rs[1]);
BENCHMARK_END (ecdsa_sign);
return GNUNET_OK;
}
/**
* Sign a given block.
*
* @param priv private key to use for the signing
* @param purpose what to sign (size, purpose)
* @param sig where to write the signature
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_eddsa_sign (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv,
const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
struct GNUNET_CRYPTO_EddsaSignature *sig)
{
gcry_sexp_t priv_sexp;
gcry_sexp_t sig_sexp;
gcry_sexp_t data;
int rc;
gcry_mpi_t rs[2];
BENCHMARK_START (eddsa_sign);
priv_sexp = decode_private_eddsa_key (priv);
data = data_to_eddsa_value (purpose);
if (0 != (rc = gcry_pk_sign (&sig_sexp, data, priv_sexp)))
{
LOG (GNUNET_ERROR_TYPE_WARNING,
_("EdDSA signing failed at %s:%d: %s\n"), __FILE__,
__LINE__, gcry_strerror (rc));
gcry_sexp_release (data);
gcry_sexp_release (priv_sexp);
return GNUNET_SYSERR;
}
gcry_sexp_release (priv_sexp);
gcry_sexp_release (data);
/* extract 'r' and 's' values from sexpression 'sig_sexp' and store in
'signature' */
if (0 != (rc = key_from_sexp (rs, sig_sexp, "sig-val", "rs")))
{
GNUNET_break (0);
gcry_sexp_release (sig_sexp);
return GNUNET_SYSERR;
}
gcry_sexp_release (sig_sexp);
GNUNET_CRYPTO_mpi_print_unsigned (sig->r, sizeof (sig->r), rs[0]);
GNUNET_CRYPTO_mpi_print_unsigned (sig->s, sizeof (sig->s), rs[1]);
gcry_mpi_release (rs[0]);
gcry_mpi_release (rs[1]);
BENCHMARK_END (eddsa_sign);
return GNUNET_OK;
}
/**
* Verify signature.
*
* @param purpose what is the purpose that the signature should have?
* @param validate block to validate (size, purpose, data)
* @param sig signature that is being validated
* @param pub public key of the signer
* @returns #GNUNET_OK if ok, #GNUNET_SYSERR if invalid
*/
int
GNUNET_CRYPTO_ecdsa_verify (uint32_t purpose,
const struct GNUNET_CRYPTO_EccSignaturePurpose *validate,
const struct GNUNET_CRYPTO_EcdsaSignature *sig,
const struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
{
gcry_sexp_t data;
gcry_sexp_t sig_sexpr;
gcry_sexp_t pub_sexpr;
int rc;
BENCHMARK_START (ecdsa_verify);
if (purpose != ntohl (validate->purpose))
return GNUNET_SYSERR; /* purpose mismatch */
/* build s-expression for signature */
if (0 != (rc = gcry_sexp_build (&sig_sexpr, NULL,
"(sig-val(ecdsa(r %b)(s %b)))",
(int) sizeof (sig->r), sig->r,
(int) sizeof (sig->s), sig->s)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
return GNUNET_SYSERR;
}
data = data_to_ecdsa_value (validate);
if (0 != (rc = gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(q %b)))",
(int) sizeof (pub->q_y), pub->q_y)))
{
gcry_sexp_release (data);
gcry_sexp_release (sig_sexpr);
return GNUNET_SYSERR;
}
rc = gcry_pk_verify (sig_sexpr, data, pub_sexpr);
gcry_sexp_release (pub_sexpr);
gcry_sexp_release (data);
gcry_sexp_release (sig_sexpr);
if (0 != rc)
{
LOG (GNUNET_ERROR_TYPE_INFO,
_("ECDSA signature verification failed at %s:%d: %s\n"), __FILE__,
__LINE__, gcry_strerror (rc));
BENCHMARK_END (ecdsa_verify);
return GNUNET_SYSERR;
}
BENCHMARK_END (ecdsa_verify);
return GNUNET_OK;
}
/**
* Verify signature.
*
* @param purpose what is the purpose that the signature should have?
* @param validate block to validate (size, purpose, data)
* @param sig signature that is being validated
* @param pub public key of the signer
* @returns #GNUNET_OK if ok, #GNUNET_SYSERR if invalid
*/
int
GNUNET_CRYPTO_eddsa_verify (uint32_t purpose,
const struct GNUNET_CRYPTO_EccSignaturePurpose *validate,
const struct GNUNET_CRYPTO_EddsaSignature *sig,
const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
{
gcry_sexp_t data;
gcry_sexp_t sig_sexpr;
gcry_sexp_t pub_sexpr;
int rc;
BENCHMARK_START (eddsa_verify);
if (purpose != ntohl (validate->purpose))
return GNUNET_SYSERR; /* purpose mismatch */
/* build s-expression for signature */
if (0 != (rc = gcry_sexp_build (&sig_sexpr, NULL,
"(sig-val(eddsa(r %b)(s %b)))",
(int)sizeof (sig->r), sig->r,
(int)sizeof (sig->s), sig->s)))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
return GNUNET_SYSERR;
}
data = data_to_eddsa_value (validate);
if (0 != (rc = gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(flags eddsa)(q %b)))",
(int)sizeof (pub->q_y), pub->q_y)))
{
gcry_sexp_release (data);
gcry_sexp_release (sig_sexpr);
return GNUNET_SYSERR;
}
rc = gcry_pk_verify (sig_sexpr, data, pub_sexpr);
gcry_sexp_release (pub_sexpr);
gcry_sexp_release (data);
gcry_sexp_release (sig_sexpr);
if (0 != rc)
{
LOG (GNUNET_ERROR_TYPE_INFO,
_("EdDSA signature verification failed at %s:%d: %s\n"), __FILE__,
__LINE__, gcry_strerror (rc));
BENCHMARK_END (eddsa_verify);
return GNUNET_SYSERR;
}
BENCHMARK_END (eddsa_verify);
return GNUNET_OK;
}
/**
* Derive key material from a public and a private ECDHE key.
*
* @param priv private key to use for the ECDH (x)
* @param pub public key to use for the ECDH (yG)
* @param key_material where to write the key material (xyG)
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecc_ecdh (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
const struct GNUNET_CRYPTO_EcdhePublicKey *pub,
struct GNUNET_HashCode *key_material)
{
gcry_mpi_point_t result;
gcry_mpi_point_t q;
gcry_mpi_t d;
gcry_ctx_t ctx;
gcry_sexp_t pub_sexpr;
gcry_mpi_t result_x;
unsigned char xbuf[256 / 8];
size_t rsize;
BENCHMARK_START (ecc_ecdh);
/* first, extract the q = dP value from the public key */
if (0 != gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(q %b)))",
(int)sizeof (pub->q_y), pub->q_y))
return GNUNET_SYSERR;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, pub_sexpr, NULL));
gcry_sexp_release (pub_sexpr);
q = gcry_mpi_ec_get_point ("q", ctx, 0);
/* second, extract the d value from our private key */
GNUNET_CRYPTO_mpi_scan_unsigned (&d, priv->d, sizeof (priv->d));
/* then call the 'multiply' function, to compute the product */
result = gcry_mpi_point_new (0);
gcry_mpi_ec_mul (result, d, q, ctx);
gcry_mpi_point_release (q);
gcry_mpi_release (d);
/* finally, convert point to string for hashing */
result_x = gcry_mpi_new (256);
if (gcry_mpi_ec_get_affine (result_x, NULL, result, ctx))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "get_affine failed", 0);
gcry_mpi_point_release (result);
gcry_ctx_release (ctx);
return GNUNET_SYSERR;
}
gcry_mpi_point_release (result);
gcry_ctx_release (ctx);
rsize = sizeof (xbuf);
GNUNET_assert (! gcry_mpi_get_flag (result_x, GCRYMPI_FLAG_OPAQUE));
/* result_x can be negative here, so we do not use 'GNUNET_CRYPTO_mpi_print_unsigned'
as that does not include the sign bit; x should be a 255-bit
value, so with the sign it should fit snugly into the 256-bit
xbuf */
GNUNET_assert (0 ==
gcry_mpi_print (GCRYMPI_FMT_STD, xbuf, rsize, &rsize,
result_x));
GNUNET_CRYPTO_hash (xbuf,
rsize,
key_material);
gcry_mpi_release (result_x);
BENCHMARK_END (ecc_ecdh);
return GNUNET_OK;
}
/**
* Derive the 'h' value for key derivation, where
* 'h = H(l,P)'.
*
* @param pub public key for deriviation
* @param label label for deriviation
* @param context additional context to use for HKDF of 'h';
* typically the name of the subsystem/application
* @return h value
*/
static gcry_mpi_t
derive_h (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub,
const char *label,
const char *context)
{
gcry_mpi_t h;
struct GNUNET_HashCode hc;
static const char *const salt = "key-derivation";
GNUNET_CRYPTO_kdf (&hc, sizeof (hc),
salt, strlen (salt),
pub, sizeof (*pub),
label, strlen (label),
context, strlen (context),
NULL, 0);
GNUNET_CRYPTO_mpi_scan_unsigned (&h,
(unsigned char *) &hc,
sizeof (hc));
return h;
}
/**
* Derive a private key from a given private key and a label.
* Essentially calculates a private key 'd = H(l,P) * x mod n'
* where n is the size of the ECC group and P is the public
* key associated with the private key 'd'.
*
* @param priv original private key
* @param label label to use for key deriviation
* @param context additional context to use for HKDF of 'h';
* typically the name of the subsystem/application
* @return derived private key
*/
struct GNUNET_CRYPTO_EcdsaPrivateKey *
GNUNET_CRYPTO_ecdsa_private_key_derive (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv,
const char *label,
const char *context)
{
struct GNUNET_CRYPTO_EcdsaPublicKey pub;
struct GNUNET_CRYPTO_EcdsaPrivateKey *ret;
gcry_mpi_t h;
gcry_mpi_t x;
gcry_mpi_t d;
gcry_mpi_t n;
gcry_ctx_t ctx;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, NULL, CURVE));
n = gcry_mpi_ec_get_mpi ("n", ctx, 1);
GNUNET_CRYPTO_ecdsa_key_get_public (priv, &pub);
h = derive_h (&pub, label, context);
GNUNET_CRYPTO_mpi_scan_unsigned (&x,
priv->d,
sizeof (priv->d));
d = gcry_mpi_new (256);
gcry_mpi_mulm (d, h, x, n);
gcry_mpi_release (h);
gcry_mpi_release (x);
gcry_mpi_release (n);
gcry_ctx_release (ctx);
ret = GNUNET_new (struct GNUNET_CRYPTO_EcdsaPrivateKey);
GNUNET_CRYPTO_mpi_print_unsigned (ret->d, sizeof (ret->d), d);
gcry_mpi_release (d);
return ret;
}
/**
* Derive a public key from a given public key and a label.
* Essentially calculates a public key 'V = H(l,P) * P'.
*
* @param pub original public key
* @param label label to use for key derivation
* @param context additional context to use for HKDF of 'h';
* typically the name of the subsystem/application
* @param result where to write the derived public key
*/
void
GNUNET_CRYPTO_ecdsa_public_key_derive (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub,
const char *label,
const char *context,
struct GNUNET_CRYPTO_EcdsaPublicKey *result)
{
gcry_ctx_t ctx;
gcry_mpi_t q_y;
gcry_mpi_t h;
gcry_mpi_t n;
gcry_mpi_t h_mod_n;
gcry_mpi_point_t q;
gcry_mpi_point_t v;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, NULL, CURVE));
/* obtain point 'q' from original public key. The provided 'q' is
compressed thus we first store it in the context and then get it
back as a (decompresssed) point. */
q_y = gcry_mpi_set_opaque_copy (NULL, pub->q_y, 8*sizeof (pub->q_y));
GNUNET_assert (NULL != q_y);
GNUNET_assert (0 == gcry_mpi_ec_set_mpi ("q", q_y, ctx));
gcry_mpi_release (q_y);
q = gcry_mpi_ec_get_point ("q", ctx, 0);
GNUNET_assert (q);
/* calculate h_mod_n = h % n */
h = derive_h (pub, label, context);
n = gcry_mpi_ec_get_mpi ("n", ctx, 1);
h_mod_n = gcry_mpi_new (256);
gcry_mpi_mod (h_mod_n, h, n);
/* calculate v = h_mod_n * q */
v = gcry_mpi_point_new (0);
gcry_mpi_ec_mul (v, h_mod_n, q, ctx);
gcry_mpi_release (h_mod_n);
gcry_mpi_release (h);
gcry_mpi_release (n);
gcry_mpi_point_release (q);
/* convert point 'v' to public key that we return */
GNUNET_assert (0 == gcry_mpi_ec_set_point ("q", v, ctx));
gcry_mpi_point_release (v);
q_y = gcry_mpi_ec_get_mpi ("q@eddsa", ctx, 0);
GNUNET_assert (q_y);
GNUNET_CRYPTO_mpi_print_unsigned (result->q_y,
sizeof (result->q_y),
q_y);
gcry_mpi_release (q_y);
gcry_ctx_release (ctx);
}
/**
* Reverse the sequence of the bytes in @a buffer
*
* @param[in|out] buffer buffer to invert
* @param length number of bytes in @a buffer
*/
static void
reverse_buffer (unsigned char *buffer,
size_t length)
{
unsigned char tmp;
size_t i;
for (i=0; i < length/2; i++)
{
tmp = buffer[i];
buffer[i] = buffer[length-1-i];
buffer[length-1-i] = tmp;
}
}
/**
* Convert the secret @a d of an EdDSA key to the
* value that is actually used in the EdDSA computation.
*
* @param d secret input
* @return value used for the calculation in EdDSA
*/
static gcry_mpi_t
eddsa_d_to_a (gcry_mpi_t d)
{
unsigned char rawmpi[32]; /* 256-bit value */
size_t rawmpilen;
unsigned char digest[64]; /* 512-bit hash value */
gcry_buffer_t hvec[2];
unsigned int b;
gcry_mpi_t a;
b = 256 / 8; /* number of bytes in `d` */
/* Note that we clear DIGEST so we can use it as input to left pad
the key with zeroes for hashing. */
memset (digest, 0, sizeof digest);
memset (hvec, 0, sizeof hvec);
rawmpilen = sizeof (rawmpi);
GNUNET_assert (0 ==
gcry_mpi_print (GCRYMPI_FMT_USG,
rawmpi, rawmpilen, &rawmpilen,
d));
hvec[0].data = digest;
hvec[0].off = 0;
hvec[0].len = b > rawmpilen ? (b - rawmpilen) : 0;
hvec[1].data = rawmpi;
hvec[1].off = 0;
hvec[1].len = rawmpilen;
GNUNET_assert (0 ==
gcry_md_hash_buffers (GCRY_MD_SHA512,
0 /* flags */,
digest,
hvec, 2));
/* Compute the A value. */
reverse_buffer (digest, 32); /* Only the first half of the hash. */
digest[0] = (digest[0] & 0x7f) | 0x40;
digest[31] &= 0xf8;
GNUNET_CRYPTO_mpi_scan_unsigned (&a,
digest,
32);
return a;
}
/**
* Take point from ECDH and convert it to key material.
*
* @param result point from ECDH
* @param ctx ECC context
* @param key_material[out] set to derived key material
* @return #GNUNET_OK on success
*/
static int
point_to_hash (gcry_mpi_point_t result,
gcry_ctx_t ctx,
struct GNUNET_HashCode *key_material)
{
gcry_mpi_t result_x;
unsigned char xbuf[256 / 8];
size_t rsize;
/* finally, convert point to string for hashing */
result_x = gcry_mpi_new (256);
if (gcry_mpi_ec_get_affine (result_x, NULL, result, ctx))
{
LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "get_affine failed", 0);
return GNUNET_SYSERR;
}
rsize = sizeof (xbuf);
GNUNET_assert (! gcry_mpi_get_flag (result_x, GCRYMPI_FLAG_OPAQUE));
/* result_x can be negative here, so we do not use 'GNUNET_CRYPTO_mpi_print_unsigned'
as that does not include the sign bit; x should be a 255-bit
value, so with the sign it should fit snugly into the 256-bit
xbuf */
GNUNET_assert (0 ==
gcry_mpi_print (GCRYMPI_FMT_STD, xbuf, rsize, &rsize,
result_x));
GNUNET_CRYPTO_hash (xbuf,
rsize,
key_material);
gcry_mpi_release (result_x);
return GNUNET_OK;
}
/**
* @ingroup crypto
* Derive key material from a ECDH public key and a private EdDSA key.
* Dual to #GNUNET_CRRYPTO_ecdh_eddsa.
*
* @param priv private key from EdDSA to use for the ECDH (x)
* @param pub public key to use for the ECDH (yG)
* @param key_material where to write the key material H(h(x)yG)
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_eddsa_ecdh (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv,
const struct GNUNET_CRYPTO_EcdhePublicKey *pub,
struct GNUNET_HashCode *key_material)
{
gcry_mpi_point_t result;
gcry_mpi_point_t q;
gcry_mpi_t d;
gcry_mpi_t a;
gcry_ctx_t ctx;
gcry_sexp_t pub_sexpr;
int ret;
BENCHMARK_START (eddsa_ecdh);
/* first, extract the q = dP value from the public key */
if (0 != gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(q %b)))",
(int)sizeof (pub->q_y), pub->q_y))
return GNUNET_SYSERR;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, pub_sexpr, NULL));
gcry_sexp_release (pub_sexpr);
q = gcry_mpi_ec_get_point ("q", ctx, 0);
/* second, extract the d value from our private key */
GNUNET_CRYPTO_mpi_scan_unsigned (&d, priv->d, sizeof (priv->d));
/* NOW, because this is EdDSA, HASH 'd' first! */
a = eddsa_d_to_a (d);
gcry_mpi_release (d);
/* then call the 'multiply' function, to compute the product */
result = gcry_mpi_point_new (0);
gcry_mpi_ec_mul (result, a, q, ctx);
gcry_mpi_point_release (q);
gcry_mpi_release (a);
ret = point_to_hash (result,
ctx,
key_material);
gcry_mpi_point_release (result);
gcry_ctx_release (ctx);
BENCHMARK_END (eddsa_ecdh);
return ret;
}
/**
* @ingroup crypto
* Derive key material from a ECDH public key and a private ECDSA key.
* Dual to #GNUNET_CRRYPTO_ecdh_eddsa.
*
* @param priv private key from ECDSA to use for the ECDH (x)
* @param pub public key to use for the ECDH (yG)
* @param key_material where to write the key material H(h(x)yG)
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecdsa_ecdh (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv,
const struct GNUNET_CRYPTO_EcdhePublicKey *pub,
struct GNUNET_HashCode *key_material)
{
gcry_mpi_point_t result;
gcry_mpi_point_t q;
gcry_mpi_t d;
gcry_ctx_t ctx;
gcry_sexp_t pub_sexpr;
int ret;
BENCHMARK_START (ecdsa_ecdh);
/* first, extract the q = dP value from the public key */
if (0 != gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(q %b)))",
(int)sizeof (pub->q_y), pub->q_y))
return GNUNET_SYSERR;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, pub_sexpr, NULL));
gcry_sexp_release (pub_sexpr);
q = gcry_mpi_ec_get_point ("q", ctx, 0);
/* second, extract the d value from our private key */
GNUNET_CRYPTO_mpi_scan_unsigned (&d, priv->d, sizeof (priv->d));
/* then call the 'multiply' function, to compute the product */
result = gcry_mpi_point_new (0);
gcry_mpi_ec_mul (result, d, q, ctx);
gcry_mpi_point_release (q);
gcry_mpi_release (d);
/* finally, convert point to string for hashing */
ret = point_to_hash (result,
ctx,
key_material);
gcry_mpi_point_release (result);
gcry_ctx_release (ctx);
BENCHMARK_END (ecdsa_ecdh);
return ret;
}
/**
* @ingroup crypto
* Derive key material from a EdDSA public key and a private ECDH key.
* Dual to #GNUNET_CRRYPTO_eddsa_ecdh.
*
* @param priv private key to use for the ECDH (y)
* @param pub public key from EdDSA to use for the ECDH (X=h(x)G)
* @param key_material where to write the key material H(yX)=H(h(x)yG)
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecdh_eddsa (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
const struct GNUNET_CRYPTO_EddsaPublicKey *pub,
struct GNUNET_HashCode *key_material)
{
gcry_mpi_point_t result;
gcry_mpi_point_t q;
gcry_mpi_t d;
gcry_ctx_t ctx;
gcry_sexp_t pub_sexpr;
int ret;
BENCHMARK_START (ecdh_eddsa);
/* first, extract the q = dP value from the public key */
if (0 != gcry_sexp_build (&pub_sexpr, NULL,
"(public-key(ecc(curve " CURVE ")(q %b)))",
(int)sizeof (pub->q_y), pub->q_y))
return GNUNET_SYSERR;
GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, pub_sexpr, NULL));
gcry_sexp_release (pub_sexpr);
q = gcry_mpi_ec_get_point ("q", ctx, 0);
/* second, extract the d value from our private key */
GNUNET_CRYPTO_mpi_scan_unsigned (&d, priv->d, sizeof (priv->d));
/* then call the 'multiply' function, to compute the product */
result = gcry_mpi_point_new (0);
gcry_mpi_ec_mul (result, d, q, ctx);
gcry_mpi_point_release (q);
gcry_mpi_release (d);
/* finally, convert point to string for hashing */
ret = point_to_hash (result,
ctx,
key_material);
gcry_mpi_point_release (result);
gcry_ctx_release (ctx);
BENCHMARK_END (ecdh_eddsa);
return ret;
}
/**
* @ingroup crypto
* Derive key material from a ECDSA public key and a private ECDH key.
* Dual to #GNUNET_CRRYPTO_eddsa_ecdh.
*
* @param priv private key to use for the ECDH (y)
* @param pub public key from ECDSA to use for the ECDH (X=h(x)G)
* @param key_material where to write the key material H(yX)=H(h(x)yG)
* @return #GNUNET_SYSERR on error, #GNUNET_OK on success
*/
int
GNUNET_CRYPTO_ecdh_ecdsa (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
const struct GNUNET_CRYPTO_EcdsaPublicKey *pub,
struct GNUNET_HashCode *key_material)
{
return GNUNET_CRYPTO_ecdh_eddsa (priv,
(const struct GNUNET_CRYPTO_EddsaPublicKey *)pub,
key_material);
}
/* end of crypto_ecc.c */