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Diffstat (limited to 'include/mbedtls/ecdsa.h')
| -rw-r--r-- | include/mbedtls/ecdsa.h | 671 |
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diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h new file mode 100644 index 0000000..2ecf349 --- /dev/null +++ b/include/mbedtls/ecdsa.h @@ -0,0 +1,671 @@ +/** + * \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 OR GPL-2.0-or-later + */ + +#ifndef MBEDTLS_ECDSA_H +#define MBEDTLS_ECDSA_H +#include "mbedtls/private_access.h" + +#include "mbedtls/build_info.h" + +#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. + * + * \note pk_wrap module assumes that "ecdsa_context" is identical + * to "ecp_keypair" (see for example structure + * "mbedtls_eckey_info" where ECDSA sign/verify functions + * are used also for EC key) + */ +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 MBEDTLS_PRIVATE(ecp); /*!< base context for ECP restart and + shared administrative info */ + mbedtls_ecdsa_restart_ver_ctx *MBEDTLS_PRIVATE(ver); /*!< ecdsa_verify() sub-context */ + mbedtls_ecdsa_restart_sig_ctx *MBEDTLS_PRIVATE(sig); /*!< ecdsa_sign() sub-context */ +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) + mbedtls_ecdsa_restart_det_ctx *MBEDTLS_PRIVATE(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_ext() 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) +/** + * \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_blind. This + * may be \c NULL if \p f_rng_blind 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 */ + +#if !defined(MBEDTLS_ECDSA_SIGN_ALT) +/** + * \brief This function computes the ECDSA signature of a + * previously-hashed message, in a restartable way. + * + * \note The deterministic version implemented in + * mbedtls_ecdsa_sign_det_restartable() is usually + * preferred. + * + * \note This function is like \c mbedtls_ecdsa_sign() but + * it can return early and restart according to the + * limit set with \c mbedtls_ecp_set_max_ops() to + * reduce blocking. + * + * \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 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. + * \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. + * \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_sign_restartable( + 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, + int (*f_rng_blind)(void *, unsigned char *, size_t), + void *p_rng_blind, + mbedtls_ecdsa_restart_ctx *rs_ctx); + +#endif /* !MBEDTLS_ECDSA_SIGN_ALT */ + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) + +/** + * \brief This function computes the ECDSA signature of a + * previously-hashed message, in a restartable way. + * + * \note This function is like \c + * mbedtls_ecdsa_sign_det_ext() but it can return + * early and restart according to the limit set with + * \c mbedtls_ecp_set_max_ops() to reduce blocking. + * + * \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_blind. This may be + * \c NULL if \p f_rng_blind doesn't need a context parameter. + * \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_sign_det_restartable( + 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, + mbedtls_ecdsa_restart_ctx *rs_ctx); + +#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 An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX + * error code on failure. + */ +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); + +#if !defined(MBEDTLS_ECDSA_VERIFY_ALT) +/** + * \brief This function verifies the ECDSA signature of a + * previously-hashed message, in a restartable manner + * + * \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. + * \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 An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX + * error code on failure. + */ +int mbedtls_ecdsa_verify_restartable(mbedtls_ecp_group *grp, + const unsigned char *buf, size_t blen, + const mbedtls_ecp_point *Q, + const mbedtls_mpi *r, + const mbedtls_mpi *s, + mbedtls_ecdsa_restart_ctx *rs_ctx); + +#endif /* !MBEDTLS_ECDSA_VERIFY_ALT */ + +/** + * \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 hlen 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 sig_size The size of the \p sig buffer in bytes. + * \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 sig_size, 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 hlen 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 sig_size The size of the \p sig buffer in bytes. + * \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 sig_size, size_t *slen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecdsa_restart_ctx *rs_ctx); + +/** + * \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 hlen 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 hlen 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 */ |