private File getSigningBase64CertificatePath() throws IOException {
        return new File(saml2Configuration.getKeystoreResource().getFile().getParentFile(), getNormalizedCertificateName() + ".pem");
    }
Sanitize String to use it as fileName for Signing Certificate Names
pac4j-saml/src/main/java/org/pac4j/saml/metadata/keystore/SAML2FileSystemKeystoreGenerator.java