OpenSSL::OCSP::CertificateId#hash_algorithm

static VALUE
ossl_ocspcid_get_hash_algorithm(VALUE self)
{
    OCSP_CERTID *id;
    ASN1_OBJECT *oid;
    BIO *out;

    GetOCSPCertId(self, id);
    OCSP_id_get0_info(NULL, &oid, NULL, NULL, id);

    if (!(out = BIO_new(BIO_s_mem())))
        ossl_raise(eOCSPError, "BIO_new");

    if (!i2a_ASN1_OBJECT(out, oid)) {
        BIO_free(out);
        ossl_raise(eOCSPError, "i2a_ASN1_OBJECT");
    }
    return ossl_membio2str(out);
}