The ECDSA Signature verification process take more that 15 minutes on MSP430F6779 controller. All dynamic memory allocation return valid memory(Verified). We are using MBEDTLS_ECP_DP_SECP256R1 curve. The same signature verification process take only a fraction of a second in MY windows PC (x64). Facing similar issue in other 32 bit micro controllers (STM32L0).
The "MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d ) ); "function take more than a minute on each iteration. The
static int ecp_mul_comb( mbedtls_ecp_group grp, mbedtls_ecp_point R,
const mbedtls_mpi m, const mbedtls_ecp_point P,
int (f_rng)(void , unsigned char *, size_t),
void *p_rng )
API call the ecp_precompute_comb() API (More than 100 times based on window size).
Is there any method avoid this delay. What could be the reason for this error behavior.
Finally the verification process failed with error code.
Each line inside ecp_precompute()_comb() taking more than 1 second to execute.
Thank for the support