aboutsummaryrefslogtreecommitdiff
path: root/lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h
diff options
context:
space:
mode:
Diffstat (limited to 'lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h')
-rw-r--r--lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h626
1 files changed, 626 insertions, 0 deletions
diff --git a/lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h b/lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h
new file mode 100644
index 0000000..264a638
--- /dev/null
+++ b/lib/mbedtls-2.27.0/include/mbedtls/ecdsa.h
@@ -0,0 +1,626 @@
+/**
+ * \file ecdsa.h
+ *
+ * \brief This file contains ECDSA definitions and functions.
+ *
+ * The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined in
+ * <em>Standards for Efficient Cryptography Group (SECG):
+ * SEC1 Elliptic Curve Cryptography</em>.
+ * The use of ECDSA for TLS is defined in <em>RFC-4492: Elliptic Curve
+ * Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS)</em>.
+ *
+ */
+/*
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MBEDTLS_ECDSA_H
+#define MBEDTLS_ECDSA_H
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#include "mbedtls/ecp.h"
+#include "mbedtls/md.h"
+
+/**
+ * \brief Maximum ECDSA signature size for a given curve bit size
+ *
+ * \param bits Curve size in bits
+ * \return Maximum signature size in bytes
+ *
+ * \note This macro returns a compile-time constant if its argument
+ * is one. It may evaluate its argument multiple times.
+ */
+/*
+ * Ecdsa-Sig-Value ::= SEQUENCE {
+ * r INTEGER,
+ * s INTEGER
+ * }
+ *
+ * For each of r and s, the value (V) may include an extra initial "0" bit.
+ */
+#define MBEDTLS_ECDSA_MAX_SIG_LEN( bits ) \
+ ( /*T,L of SEQUENCE*/ ( ( bits ) >= 61 * 8 ? 3 : 2 ) + \
+ /*T,L of r,s*/ 2 * ( ( ( bits ) >= 127 * 8 ? 3 : 2 ) + \
+ /*V of r,s*/ ( ( bits ) + 8 ) / 8 ) )
+
+/** The maximal size of an ECDSA signature in Bytes. */
+#define MBEDTLS_ECDSA_MAX_LEN MBEDTLS_ECDSA_MAX_SIG_LEN( MBEDTLS_ECP_MAX_BITS )
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief The ECDSA context structure.
+ *
+ * \warning Performing multiple operations concurrently on the same
+ * ECDSA context is not supported; objects of this type
+ * should not be shared between multiple threads.
+ */
+typedef mbedtls_ecp_keypair mbedtls_ecdsa_context;
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+
+/**
+ * \brief Internal restart context for ecdsa_verify()
+ *
+ * \note Opaque struct, defined in ecdsa.c
+ */
+typedef struct mbedtls_ecdsa_restart_ver mbedtls_ecdsa_restart_ver_ctx;
+
+/**
+ * \brief Internal restart context for ecdsa_sign()
+ *
+ * \note Opaque struct, defined in ecdsa.c
+ */
+typedef struct mbedtls_ecdsa_restart_sig mbedtls_ecdsa_restart_sig_ctx;
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+/**
+ * \brief Internal restart context for ecdsa_sign_det()
+ *
+ * \note Opaque struct, defined in ecdsa.c
+ */
+typedef struct mbedtls_ecdsa_restart_det mbedtls_ecdsa_restart_det_ctx;
+#endif
+
+/**
+ * \brief General context for resuming ECDSA operations
+ */
+typedef struct
+{
+ mbedtls_ecp_restart_ctx ecp; /*!< base context for ECP restart and
+ shared administrative info */
+ mbedtls_ecdsa_restart_ver_ctx *ver; /*!< ecdsa_verify() sub-context */
+ mbedtls_ecdsa_restart_sig_ctx *sig; /*!< ecdsa_sign() sub-context */
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+ mbedtls_ecdsa_restart_det_ctx *det; /*!< ecdsa_sign_det() sub-context */
+#endif
+} mbedtls_ecdsa_restart_ctx;
+
+#else /* MBEDTLS_ECP_RESTARTABLE */
+
+/* Now we can declare functions that take a pointer to that */
+typedef void mbedtls_ecdsa_restart_ctx;
+
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
+/**
+ * \brief This function checks whether a given group can be used
+ * for ECDSA.
+ *
+ * \param gid The ECP group ID to check.
+ *
+ * \return \c 1 if the group can be used, \c 0 otherwise
+ */
+int mbedtls_ecdsa_can_do( mbedtls_ecp_group_id gid );
+
+/**
+ * \brief This function computes the ECDSA signature of a
+ * previously-hashed message.
+ *
+ * \note The deterministic version implemented in
+ * mbedtls_ecdsa_sign_det() is usually preferred.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated
+ * as defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.3, step 5.
+ *
+ * \see ecp.h
+ *
+ * \param grp The context for the elliptic curve to use.
+ * This must be initialized and have group parameters
+ * set, for example through mbedtls_ecp_group_load().
+ * \param r The MPI context in which to store the first part
+ * the signature. This must be initialized.
+ * \param s The MPI context in which to store the second part
+ * the signature. This must be initialized.
+ * \param d The private signing key. This must be initialized.
+ * \param buf The content to be signed. This is usually the hash of
+ * the original data to be signed. This must be a readable
+ * buffer of length \p blen Bytes. It may be \c NULL if
+ * \p blen is zero.
+ * \param blen The length of \p buf in Bytes.
+ * \param f_rng The RNG function. This must not be \c NULL.
+ * \param p_rng The RNG context to be passed to \p f_rng. This may be
+ * \c NULL if \p f_rng doesn't need a context parameter.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX
+ * or \c MBEDTLS_MPI_XXX error code on failure.
+ */
+int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
+ const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
+#if defined(MBEDTLS_DEPRECATED_WARNING)
+#define MBEDTLS_DEPRECATED __attribute__((deprecated))
+#else
+#define MBEDTLS_DEPRECATED
+#endif
+/**
+ * \brief This function computes the ECDSA signature of a
+ * previously-hashed message, deterministic version.
+ *
+ * For more information, see <em>RFC-6979: Deterministic
+ * Usage of the Digital Signature Algorithm (DSA) and Elliptic
+ * Curve Digital Signature Algorithm (ECDSA)</em>.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.3, step 5.
+ *
+ * \warning Since the output of the internal RNG is always the same for
+ * the same key and message, this limits the efficiency of
+ * blinding and leaks information through side channels. For
+ * secure behavior use mbedtls_ecdsa_sign_det_ext() instead.
+ *
+ * (Optimally the blinding is a random value that is different
+ * on every execution. In this case the blinding is still
+ * random from the attackers perspective, but is the same on
+ * each execution. This means that this blinding does not
+ * prevent attackers from recovering secrets by combining
+ * several measurement traces, but may prevent some attacks
+ * that exploit relationships between secret data.)
+ *
+ * \see ecp.h
+ *
+ * \param grp The context for the elliptic curve to use.
+ * This must be initialized and have group parameters
+ * set, for example through mbedtls_ecp_group_load().
+ * \param r The MPI context in which to store the first part
+ * the signature. This must be initialized.
+ * \param s The MPI context in which to store the second part
+ * the signature. This must be initialized.
+ * \param d The private signing key. This must be initialized
+ * and setup, for example through mbedtls_ecp_gen_privkey().
+ * \param buf The hashed content to be signed. This must be a readable
+ * buffer of length \p blen Bytes. It may be \c NULL if
+ * \p blen is zero.
+ * \param blen The length of \p buf in Bytes.
+ * \param md_alg The hash algorithm used to hash the original data.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX
+ * error code on failure.
+ */
+int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r,
+ mbedtls_mpi *s, const mbedtls_mpi *d,
+ const unsigned char *buf, size_t blen,
+ mbedtls_md_type_t md_alg ) MBEDTLS_DEPRECATED;
+#undef MBEDTLS_DEPRECATED
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+
+/**
+ * \brief This function computes the ECDSA signature of a
+ * previously-hashed message, deterministic version.
+ *
+ * For more information, see <em>RFC-6979: Deterministic
+ * Usage of the Digital Signature Algorithm (DSA) and Elliptic
+ * Curve Digital Signature Algorithm (ECDSA)</em>.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.3, step 5.
+ *
+ * \see ecp.h
+ *
+ * \param grp The context for the elliptic curve to use.
+ * This must be initialized and have group parameters
+ * set, for example through mbedtls_ecp_group_load().
+ * \param r The MPI context in which to store the first part
+ * the signature. This must be initialized.
+ * \param s The MPI context in which to store the second part
+ * the signature. This must be initialized.
+ * \param d The private signing key. This must be initialized
+ * and setup, for example through mbedtls_ecp_gen_privkey().
+ * \param buf The hashed content to be signed. This must be a readable
+ * buffer of length \p blen Bytes. It may be \c NULL if
+ * \p blen is zero.
+ * \param blen The length of \p buf in Bytes.
+ * \param md_alg The hash algorithm used to hash the original data.
+ * \param f_rng_blind The RNG function used for blinding. This must not be
+ * \c NULL.
+ * \param p_rng_blind The RNG context to be passed to \p f_rng. This may be
+ * \c NULL if \p f_rng doesn't need a context parameter.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX
+ * error code on failure.
+ */
+int mbedtls_ecdsa_sign_det_ext( mbedtls_ecp_group *grp, mbedtls_mpi *r,
+ mbedtls_mpi *s, const mbedtls_mpi *d,
+ const unsigned char *buf, size_t blen,
+ mbedtls_md_type_t md_alg,
+ int (*f_rng_blind)(void *, unsigned char *, size_t),
+ void *p_rng_blind );
+#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
+
+/**
+ * \brief This function verifies the ECDSA signature of a
+ * previously-hashed message.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.4, step 3.
+ *
+ * \see ecp.h
+ *
+ * \param grp The ECP group to use.
+ * This must be initialized and have group parameters
+ * set, for example through mbedtls_ecp_group_load().
+ * \param buf The hashed content that was signed. This must be a readable
+ * buffer of length \p blen Bytes. It may be \c NULL if
+ * \p blen is zero.
+ * \param blen The length of \p buf in Bytes.
+ * \param Q The public key to use for verification. This must be
+ * initialized and setup.
+ * \param r The first integer of the signature.
+ * This must be initialized.
+ * \param s The second integer of the signature.
+ * This must be initialized.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the signature
+ * is invalid.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX
+ * error code on failure for any other reason.
+ */
+int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
+ const unsigned char *buf, size_t blen,
+ const mbedtls_ecp_point *Q, const mbedtls_mpi *r,
+ const mbedtls_mpi *s);
+
+/**
+ * \brief This function computes the ECDSA signature and writes it
+ * to a buffer, serialized as defined in <em>RFC-4492:
+ * Elliptic Curve Cryptography (ECC) Cipher Suites for
+ * Transport Layer Security (TLS)</em>.
+ *
+ * \warning It is not thread-safe to use the same context in
+ * multiple threads.
+ *
+ * \note The deterministic version is used if
+ * #MBEDTLS_ECDSA_DETERMINISTIC is defined. For more
+ * information, see <em>RFC-6979: Deterministic Usage
+ * of the Digital Signature Algorithm (DSA) and Elliptic
+ * Curve Digital Signature Algorithm (ECDSA)</em>.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.3, step 5.
+ *
+ * \see ecp.h
+ *
+ * \param ctx The ECDSA context to use. This must be initialized
+ * and have a group and private key bound to it, for example
+ * via mbedtls_ecdsa_genkey() or mbedtls_ecdsa_from_keypair().
+ * \param md_alg The message digest that was used to hash the message.
+ * \param hash The message hash to be signed. This must be a readable
+ * buffer of length \p blen Bytes.
+ * \param hlen The length of the hash \p hash in Bytes.
+ * \param sig The buffer to which to write the signature. This must be a
+ * writable buffer of length at least twice as large as the
+ * size of the curve used, plus 9. For example, 73 Bytes if
+ * a 256-bit curve is used. A buffer length of
+ * #MBEDTLS_ECDSA_MAX_LEN is always safe.
+ * \param slen The address at which to store the actual length of
+ * the signature written. Must not be \c NULL.
+ * \param f_rng The RNG function. This must not be \c NULL if
+ * #MBEDTLS_ECDSA_DETERMINISTIC is unset. Otherwise,
+ * it is used only for blinding and may be set to \c NULL, but
+ * doing so is DEPRECATED.
+ * \param p_rng The RNG context to be passed to \p f_rng. This may be
+ * \c NULL if \p f_rng is \c NULL or doesn't use a context.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX, \c MBEDTLS_ERR_MPI_XXX or
+ * \c MBEDTLS_ERR_ASN1_XXX error code on failure.
+ */
+int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hlen,
+ unsigned char *sig, size_t *slen,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng );
+
+/**
+ * \brief This function computes the ECDSA signature and writes it
+ * to a buffer, in a restartable way.
+ *
+ * \see \c mbedtls_ecdsa_write_signature()
+ *
+ * \note This function is like \c mbedtls_ecdsa_write_signature()
+ * but it can return early and restart according to the limit
+ * set with \c mbedtls_ecp_set_max_ops() to reduce blocking.
+ *
+ * \param ctx The ECDSA context to use. This must be initialized
+ * and have a group and private key bound to it, for example
+ * via mbedtls_ecdsa_genkey() or mbedtls_ecdsa_from_keypair().
+ * \param md_alg The message digest that was used to hash the message.
+ * \param hash The message hash to be signed. This must be a readable
+ * buffer of length \p blen Bytes.
+ * \param hlen The length of the hash \p hash in Bytes.
+ * \param sig The buffer to which to write the signature. This must be a
+ * writable buffer of length at least twice as large as the
+ * size of the curve used, plus 9. For example, 73 Bytes if
+ * a 256-bit curve is used. A buffer length of
+ * #MBEDTLS_ECDSA_MAX_LEN is always safe.
+ * \param slen The address at which to store the actual length of
+ * the signature written. Must not be \c NULL.
+ * \param f_rng The RNG function. This must not be \c NULL if
+ * #MBEDTLS_ECDSA_DETERMINISTIC is unset. Otherwise,
+ * it is unused and may be set to \c NULL.
+ * \param p_rng The RNG context to be passed to \p f_rng. This may be
+ * \c NULL if \p f_rng is \c NULL or doesn't use a context.
+ * \param rs_ctx The restart context to use. This may be \c NULL to disable
+ * restarting. If it is not \c NULL, it must point to an
+ * initialized restart context.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
+ * operations was reached: see \c mbedtls_ecp_set_max_ops().
+ * \return Another \c MBEDTLS_ERR_ECP_XXX, \c MBEDTLS_ERR_MPI_XXX or
+ * \c MBEDTLS_ERR_ASN1_XXX error code on failure.
+ */
+int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hlen,
+ unsigned char *sig, size_t *slen,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng,
+ mbedtls_ecdsa_restart_ctx *rs_ctx );
+
+#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
+#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
+#if defined(MBEDTLS_DEPRECATED_WARNING)
+#define MBEDTLS_DEPRECATED __attribute__((deprecated))
+#else
+#define MBEDTLS_DEPRECATED
+#endif
+/**
+ * \brief This function computes an ECDSA signature and writes
+ * it to a buffer, serialized as defined in <em>RFC-4492:
+ * Elliptic Curve Cryptography (ECC) Cipher Suites for
+ * Transport Layer Security (TLS)</em>.
+ *
+ * The deterministic version is defined in <em>RFC-6979:
+ * Deterministic Usage of the Digital Signature Algorithm (DSA)
+ * and Elliptic Curve Digital Signature Algorithm (ECDSA)</em>.
+ *
+ * \warning It is not thread-safe to use the same context in
+ * multiple threads.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.3, step 5.
+ *
+ * \see ecp.h
+ *
+ * \deprecated Superseded by mbedtls_ecdsa_write_signature() in
+ * Mbed TLS version 2.0 and later.
+ *
+ * \param ctx The ECDSA context to use. This must be initialized
+ * and have a group and private key bound to it, for example
+ * via mbedtls_ecdsa_genkey() or mbedtls_ecdsa_from_keypair().
+ * \param hash The message hash to be signed. This must be a readable
+ * buffer of length \p blen Bytes.
+ * \param hlen The length of the hash \p hash in Bytes.
+ * \param sig The buffer to which to write the signature. This must be a
+ * writable buffer of length at least twice as large as the
+ * size of the curve used, plus 9. For example, 73 Bytes if
+ * a 256-bit curve is used. A buffer length of
+ * #MBEDTLS_ECDSA_MAX_LEN is always safe.
+ * \param slen The address at which to store the actual length of
+ * the signature written. Must not be \c NULL.
+ * \param md_alg The message digest that was used to hash the message.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX, \c MBEDTLS_ERR_MPI_XXX or
+ * \c MBEDTLS_ERR_ASN1_XXX error code on failure.
+ */
+int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,
+ const unsigned char *hash, size_t hlen,
+ unsigned char *sig, size_t *slen,
+ mbedtls_md_type_t md_alg ) MBEDTLS_DEPRECATED;
+#undef MBEDTLS_DEPRECATED
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
+
+/**
+ * \brief This function reads and verifies an ECDSA signature.
+ *
+ * \note If the bitlength of the message hash is larger than the
+ * bitlength of the group order, then the hash is truncated as
+ * defined in <em>Standards for Efficient Cryptography Group
+ * (SECG): SEC1 Elliptic Curve Cryptography</em>, section
+ * 4.1.4, step 3.
+ *
+ * \see ecp.h
+ *
+ * \param ctx The ECDSA context to use. This must be initialized
+ * and have a group and public key bound to it.
+ * \param hash The message hash that was signed. This must be a readable
+ * buffer of length \p size Bytes.
+ * \param hlen The size of the hash \p hash.
+ * \param sig The signature to read and verify. This must be a readable
+ * buffer of length \p slen Bytes.
+ * \param slen The size of \p sig in Bytes.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid.
+ * \return #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if there is a valid
+ * signature in \p sig, but its length is less than \p siglen.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_ERR_MPI_XXX
+ * error code on failure for any other reason.
+ */
+int mbedtls_ecdsa_read_signature( mbedtls_ecdsa_context *ctx,
+ const unsigned char *hash, size_t hlen,
+ const unsigned char *sig, size_t slen );
+
+/**
+ * \brief This function reads and verifies an ECDSA signature,
+ * in a restartable way.
+ *
+ * \see \c mbedtls_ecdsa_read_signature()
+ *
+ * \note This function is like \c mbedtls_ecdsa_read_signature()
+ * but it can return early and restart according to the limit
+ * set with \c mbedtls_ecp_set_max_ops() to reduce blocking.
+ *
+ * \param ctx The ECDSA context to use. This must be initialized
+ * and have a group and public key bound to it.
+ * \param hash The message hash that was signed. This must be a readable
+ * buffer of length \p size Bytes.
+ * \param hlen The size of the hash \p hash.
+ * \param sig The signature to read and verify. This must be a readable
+ * buffer of length \p slen Bytes.
+ * \param slen The size of \p sig in Bytes.
+ * \param rs_ctx The restart context to use. This may be \c NULL to disable
+ * restarting. If it is not \c NULL, it must point to an
+ * initialized restart context.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid.
+ * \return #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if there is a valid
+ * signature in \p sig, but its length is less than \p siglen.
+ * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
+ * operations was reached: see \c mbedtls_ecp_set_max_ops().
+ * \return Another \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_ERR_MPI_XXX
+ * error code on failure for any other reason.
+ */
+int mbedtls_ecdsa_read_signature_restartable( mbedtls_ecdsa_context *ctx,
+ const unsigned char *hash, size_t hlen,
+ const unsigned char *sig, size_t slen,
+ mbedtls_ecdsa_restart_ctx *rs_ctx );
+
+/**
+ * \brief This function generates an ECDSA keypair on the given curve.
+ *
+ * \see ecp.h
+ *
+ * \param ctx The ECDSA context to store the keypair in.
+ * This must be initialized.
+ * \param gid The elliptic curve to use. One of the various
+ * \c MBEDTLS_ECP_DP_XXX macros depending on configuration.
+ * \param f_rng The RNG function to use. This must not be \c NULL.
+ * \param p_rng The RNG context to be passed to \p f_rng. This may be
+ * \c NULL if \p f_rng doesn't need a context argument.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX code on failure.
+ */
+int mbedtls_ecdsa_genkey( mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
+/**
+ * \brief This function sets up an ECDSA context from an EC key pair.
+ *
+ * \see ecp.h
+ *
+ * \param ctx The ECDSA context to setup. This must be initialized.
+ * \param key The EC key to use. This must be initialized and hold
+ * a private-public key pair or a public key. In the former
+ * case, the ECDSA context may be used for signature creation
+ * and verification after this call. In the latter case, it
+ * may be used for signature verification.
+ *
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX code on failure.
+ */
+int mbedtls_ecdsa_from_keypair( mbedtls_ecdsa_context *ctx,
+ const mbedtls_ecp_keypair *key );
+
+/**
+ * \brief This function initializes an ECDSA context.
+ *
+ * \param ctx The ECDSA context to initialize.
+ * This must not be \c NULL.
+ */
+void mbedtls_ecdsa_init( mbedtls_ecdsa_context *ctx );
+
+/**
+ * \brief This function frees an ECDSA context.
+ *
+ * \param ctx The ECDSA context to free. This may be \c NULL,
+ * in which case this function does nothing. If it
+ * is not \c NULL, it must be initialized.
+ */
+void mbedtls_ecdsa_free( mbedtls_ecdsa_context *ctx );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+/**
+ * \brief Initialize a restart context.
+ *
+ * \param ctx The restart context to initialize.
+ * This must not be \c NULL.
+ */
+void mbedtls_ecdsa_restart_init( mbedtls_ecdsa_restart_ctx *ctx );
+
+/**
+ * \brief Free the components of a restart context.
+ *
+ * \param ctx The restart context to free. This may be \c NULL,
+ * in which case this function does nothing. If it
+ * is not \c NULL, it must be initialized.
+ */
+void mbedtls_ecdsa_restart_free( mbedtls_ecdsa_restart_ctx *ctx );
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ecdsa.h */