public byte[] decode(final byte[] base64) {
        if (null == base64) {
            return null;
        }

        try {
            return getMimeDecoder().decode(base64);
        } catch (final IllegalArgumentException e) {
            return EMPTY_BYTES;
        }
    }
Decode Base64-encoded bytes to their original form, using specifications from this codec instance
httpclient5/src/main/java/org/apache/hc/client5/http/utils/Base64.java