yas - Yet Another SCOS
Richard Heathfield, from the Usenet Group sci.crypt, introduced
his SCOS (sci.crypt open secret) a while ago to the community.
This is an enhanced version of SCOS, using base64 and allowing binary input.
The cool thing about yas is, that now you don't know if it is a standard base64 encoded message or not. :-)
Usage: $ yas e 0 63 < infile > outfile. $ yas d 0 63 < infile > outfile
Allowed numbers must be between 0 and 63.