static VALUE
ossl_pkcs7si_initialize(VALUE self, VALUE cert, VALUE key, VALUE digest)
{
    PKCS7_SIGNER_INFO *p7si;
    EVP_PKEY *pkey;
    X509 *x509;
    const EVP_MD *md;

    pkey = GetPrivPKeyPtr(key); /* NO NEED TO DUP */
    x509 = GetX509CertPtr(cert); /* NO NEED TO DUP */
    md = ossl_evp_get_digestbyname(digest);
    GetPKCS7si(self, p7si);
    if (!(PKCS7_SIGNER_INFO_set(p7si, x509, pkey, (EVP_MD*)md))) {
        ossl_raise(ePKCS7Error, NULL);
    }

    return self;
}

static VALUE
ossl_pkcs7si_get_issuer(VALUE self)
{
    PKCS7_SIGNER_INFO *p7si;

    GetPKCS7si(self, p7si);

    return ossl_x509name_new(p7si->issuer_and_serial->issuer);
}

static VALUE
ossl_pkcs7si_get_serial(VALUE self)
{
    PKCS7_SIGNER_INFO *p7si;

    GetPKCS7si(self, p7si);

    return asn1integer_to_num(p7si->issuer_and_serial->serial);
}

static VALUE
ossl_pkcs7si_get_signed_time(VALUE self)
{
    PKCS7_SIGNER_INFO *p7si;
    ASN1_TYPE *asn1obj;

    GetPKCS7si(self, p7si);

    if (!(asn1obj = PKCS7_get_signed_attribute(p7si, NID_pkcs9_signingTime))) {
        ossl_raise(ePKCS7Error, NULL);
    }
    if (asn1obj->type == V_ASN1_UTCTIME) {
        return asn1time_to_time(asn1obj->value.utctime);
    }
    /*
     * OR
     * ossl_raise(ePKCS7Error, "...");
     * ?
     */

    return Qnil;
}