Certificate
https://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
https://www.cs.auckland.ac.nz/~pgut001/pubs/pkitutorial.pdf
http://kvazar.files.wordpress.com/2008/12/unencrypted.pdf
https://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
https://www.cs.auckland.ac.nz/~pgut001/pubs/pkitutorial.pdf
http://kvazar.files.wordpress.com/2008/12/unencrypted.pdf