Document parameter preconditions in ECDSA module

This commit is contained in:
Hanno Becker 2018-12-14 16:43:20 +00:00
parent af0c6cb9e0
commit e2e509ca5d

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@ -118,7 +118,8 @@ typedef void mbedtls_ecdsa_restart_ctx;
* \brief This function computes the ECDSA signature of a
* previously-hashed message.
*
* \note The deterministic version is usually preferred.
* \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
@ -128,14 +129,22 @@ typedef void mbedtls_ecdsa_restart_ctx;
*
* \see ecp.h
*
* \param grp The ECP group.
* \param r The first output integer.
* \param s The second output integer.
* \param d The private signing key.
* \param buf The message hash.
* \param blen The length of \p buf.
* \param f_rng The RNG function.
* \param p_rng The RNG context.
* \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
@ -162,20 +171,28 @@ int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
*
* \see ecp.h
*
* \param grp The ECP group.
* \param r The first output integer.
* \param s The second output integer.
* \param d The private signing key.
* \param buf The message hash.
* \param blen The length of \p buf.
* \param md_alg The MD algorithm used to hash the message.
* \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,
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 );
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
@ -191,12 +208,19 @@ int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi
*
* \see ecp.h
*
* \param grp The ECP group.
* \param buf The message hash.
* \param blen The length of \p buf.
* \param Q The public key to use for verification.
* \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
@ -206,7 +230,8 @@ int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi
*/
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);
const mbedtls_ecp_point *Q, const mbedtls_mpi *r,
const mbedtls_mpi *s);
/**
* \brief This function computes the ECDSA signature and writes it
@ -223,11 +248,6 @@ int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
* of the Digital Signature Algorithm (DSA) and Elliptic
* Curve Digital Signature Algorithm (ECDSA)</em>.
*
* \note The \p sig buffer must be 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.
*
* \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
@ -236,20 +256,32 @@ int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
*
* \see ecp.h
*
* \param ctx The ECDSA context.
* \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.
* \param hlen The length of the hash.
* \param sig The buffer that holds the signature.
* \param slen The length of the signature written.
* \param f_rng The RNG function.
* \param p_rng The RNG context.
* \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.
*
* \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,
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),
@ -265,15 +297,28 @@ int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t
* 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.
* \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.
* \param hlen The length of the hash.
* \param sig The buffer that holds the signature.
* \param slen The length of the signature written.
* \param f_rng The RNG function.
* \param p_rng The RNG context.
* \param rs_ctx The restart context (NULL disables restart).
* \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
@ -309,11 +354,6 @@ int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
* \warning It is not thread-safe to use the same context in
* multiple threads.
*
* \note The \p sig buffer must be 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.
*
* \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
@ -325,12 +365,20 @@ int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
* \deprecated Superseded by mbedtls_ecdsa_write_signature() in
* Mbed TLS version 2.0 and later.
*
* \param ctx The ECDSA context.
* \param hash The message hash.
* \param hlen The length of the hash.
* \param sig The buffer that holds the signature.
* \param slen The length of the signature written.
* \param md_alg The MD algorithm used to hash the message.
* \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
@ -355,11 +403,14 @@ int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,
*
* \see ecp.h
*
* \param ctx The ECDSA context.
* \param hash The message hash.
* \param hlen The size of the hash.
* \param sig The signature to read and verify.
* \param slen The size of \p sig.
* \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.
@ -382,12 +433,17 @@ int mbedtls_ecdsa_read_signature( mbedtls_ecdsa_context *ctx,
* 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.
* \param hash The message hash.
* \param hlen The size of the hash.
* \param sig The signature to read and verify.
* \param slen The size of \p sig.
* \param rs_ctx The restart context (NULL disables restart).
* \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.
@ -409,10 +465,12 @@ int mbedtls_ecdsa_read_signature_restartable( mbedtls_ecdsa_context *ctx,
* \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.
* \param p_rng The RNG context.
* \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.
@ -425,36 +483,51 @@ int mbedtls_ecdsa_genkey( mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
*
* \see ecp.h
*
* \param ctx The ECDSA context to set.
* \param key The EC key to use.
* \param ctx The ECDSA context to set. 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
* 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 );
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.
* \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
* \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
* \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 */