RFR 8074935: jdk8 keytool doesn't validate pem files for RFC 1421 correctness, as jdk7 did

[Wang Weijun]

Hi All

Please review the code change at

   http://cr.openjdk.java.net/~weijun/8074935/webrev.00/

In jdk8, we use Base64.getMimeDecoder() to parse PEM-encoded certs and it ignores every character not in the base-64 alphabet. PEM is more restricted and as I know openssl rejects PEM with illegal chars (Ex, "!" as in bug report and test). This fix will also reject them.

I also updated the encode side so that the output is always 64 chars wide, which is a requirement of PEM (http://en.wikipedia.org/wiki/Base64#Privacy-enhanced_mail).

Thanks
Max