Hi:
A quick search on support.sas.com using the search string:
encrypt PCI
returned this as the first hit:
http://support.sas.com/kb/19/851.html
Again searching support.sas.com for just the terms
encrypt documentation
returned several documentation links. Here's one of them:
http://support.sas.com/documentation/onlinedoc/91pdf/sasdoc_91/base_lrdictionary_6973.pdf
For more help with encryption, especially if you are working with products other than just Base SAS (like Integration Technologies), you might consider contacting Tech Support.
cynthia