SonarCloud complains we are using the String.replaceAll() method that creates Pattern internally every time:

    /**
     * Decodes a PEM-encoded block.
     *
     * @param input the input string, according to RFC 1421, can only contain
     * characters in the base-64 alphabet and whitespaces.
     * @return the decoded bytes
     */
    public static byte[] decode(String input) {
        byte[] src = input.replaceAll("\\s+", "").
            getBytes(StandardCharsets.ISO_8859_1);
            return Base64.getDecoder().decode(src);
    }


We already have cached Patterns for other cases, we should do the same here.