use internal SHA256Thumbprint api

Change-Id: I6a51359af58dbb79b6a0399944030dbcbe97152b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/130963
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
(cherry picked from commit f30bc3ccdfb48356910d64ee4a3dda685b11de93)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/131202
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
diff --git a/xmlsecurity/source/component/documentdigitalsignatures.cxx b/xmlsecurity/source/component/documentdigitalsignatures.cxx
index 8b365a1..4e714014 100644
--- a/xmlsecurity/source/component/documentdigitalsignatures.cxx
+++ b/xmlsecurity/source/component/documentdigitalsignatures.cxx
@@ -19,9 +19,10 @@

#include <resourcemanager.hxx>

#include <digitalsignaturesdialog.hxx>
#include <certificate.hxx>
#include <certificatechooser.hxx>
#include <certificateviewer.hxx>
#include <digitalsignaturesdialog.hxx>
#include <macrosecurity.hxx>
#include <biginteger.hxx>
#include <strings.hrc>
@@ -676,6 +677,12 @@ sal_Bool DocumentDigitalSignatures::isAuthorTrusted(
            if (!aSignatureManager.init())
                return false;
            uno::Reference<css::security::XCertificate> xCert = aSignatureManager.getSecurityEnvironment()->createCertificateFromAscii(rAuthor.RawData);

            auto pAuthor = dynamic_cast<xmlsecurity::Certificate*>(xAuthor.get());
            auto pCert = dynamic_cast<xmlsecurity::Certificate*>(xCert.get());
            if (pAuthor && pCert)
                return pCert->getSHA256Thumbprint() == pAuthor->getSHA256Thumbprint();

            return xCert->getSHA1Thumbprint() == xAuthor->getSHA1Thumbprint();
        });
}