[openssl-users] Fixed-size digest using EVP with algos ECDSA+SHA256
daniel.andrade at tecnico.ulisboa.pt
Mon Aug 7 19:08:07 UTC 2017
I'm writing functions to create a digest of a data buffer using
ECDSA+SHA256. I've been trying to work with only the high-level EVP
interface, and not use the low-level interfaces.
My understanding is that the resulting digest is an ASN.1 structure. I
have to feed this digest to the Intel SGX runtime, which requires a
fixed-size input (they actually have two separates arrays, one for X and
one for Y, each with 32-byte length).
Is it possible to get a fixed-sized digest using ECDSA/SHA256, I mean
does OpenSSL have functions for this? Or could someone give me some
pointers on how to proceed to convert that result to the 64-byte fixed size?
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