mbedtls_ecdsa_sign_restartable() function

This function computes the ECDSA signature of a previously-hashed message, in a restartable way. \see ecp.h

Syntax

Show:

Summary

Declaration

Definition

from ecdsa.h:269

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);

Implemented in ecdsa.c:243

Arguments

Argument

Declared as

Description

grp

mbedtls_ecp_group *

The context for the elliptic curve to use. This must be initialized and have group parameters set, for example through mbedtls_ecp_group_load().

mbedtls_mpi *

The MPI context in which to store the first part the signature. This must be initialized.

mbedtls_mpi *

The MPI context in which to store the second part the signature. This must be initialized.

const mbedtls_mpi *

The private signing key. This must be initialized and setup, for example through mbedtls_ecp_gen_privkey().

buf

const unsigned char *

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.

blen

size_t

The length of \p buf in Bytes.

f_rng

int (*)(void *, unsigned char *, size_t)

The RNG function. This must not be \c NULL.

p_rng

void *

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.

f_rng_blind

int (*)(void *, unsigned char *, size_t)

The RNG function used for blinding. This must not be \c NULL.

p_rng_blind

void *

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.

rs_ctx

mbedtls_ecdsa_restart_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 value

\c 0 on success. #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of operations was reached: see \c mbedtls_ecp_set_max_ops(). Another \c MBEDTLS_ERR_ECP_XXX, \c MBEDTLS_ERR_MPI_XXX or \c MBEDTLS_ERR_ASN1_XXX error code on failure.

Notes

The deterministic version implemented in mbedtls_ecdsa_sign_det_restartable() is usually preferred. 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. If the bitlength of the message hash is larger than the bitlength of the group order, then the hash is truncated as defined in Standards for Efficient Cryptography Group (SECG): SEC1 Elliptic Curve Cryptography, section 4.1.3, step 5.