Please take a review at http://cr.openjdk.java.net/~weijun/8208602/webrev.00/
https://tools.ietf.org/html/rfc7468#section-3 explicitly allows WSP after the header/footer: textualmsg = preeb *WSP eol *eolWSP base64text posteb *WSP [eol] preeb = "-----BEGIN " label "-----" ;... ;... posteb = "-----END " label "-----" ;... Thanks Max