
The original one-way encryption I put into Multics about 1968 (as suggested

by Joe Weizenbaum) was invertible.  An Air Force tiger team demonstrated 
this to me in May 1973.  I then asked an expert (who requested anonymity) 
what I should use instead; the expert's suggestion was to treat the 
8-byte password as both key and data for the LUCIFER encryption algorithm, 
which is similar or identical to DES.  This method or something stronger 
should take care of (a).  Issue (b) is discussed in comp.security.misc: 
longer passwords and quality control on what users can choose as passwords
are the common tactics.