Hi all, I have some problems with mbedTLS during ECDSA signing process.
I followed the example supplied with the source code and write this code:
mbedtls_pk_init(&pk); mbedtls_pk_parse_key(&pk, (const unsigned char *) flash.flash_ver0.ecc_priv_key, strlen(flash.flash_ver0.ecc_priv_key) + 1, (const unsigned char *)CA_DEF_ISSUER_PWD, CA_DEF_ISSUER_PWD_LEN); mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), msg, msg_len, hash); mbedtls_pk_sign(&pk, MBEDTLS_MD_SHA256, hash, 0, tmp, (size_t *)&len, mbedtls_ctr_drbg_random, &ctr_drbg);
The private key is an ECC key with 384 bit. I have two issue:
1) In tmp variable I found the signature, but it is 72 byte, instead of 96 (384*2/87); 2) On this signature I try to make a verify, but fails.
Where I'm wrong?
Best regards, Stefano