private String getNormalizedCertificateName() {
        val certName = new StringBuilder(CERTIFICATES_PREFIX);
        if (StringUtils.isNotBlank(saml2Configuration.getCertificateNameToAppend())) {
            certName.append('-');
            certName.append(NORMALIZE_PATTERN.matcher(saml2Configuration.getCertificateNameToAppend())
                .replaceAll(Pac4jConstants.EMPTY_STRING));
        }
        return certName.toString();
    }
Sanitize String to use it as fileName for Signing Certificate Names
pac4j-saml/src/main/java/org/pac4j/saml/metadata/keystore/SAML2FileSystemKeystoreGenerator.java