ream
ciphers such as Arcfour can operate in only one mode, <TT>stream</TT>.
Block ciphers such as AES and DES can operate in several different
modes:</P><UL><LI>ECB</LI><LI>CBC</LI><LI>OFB</LI><LI>CFB (note that Ironclad's CFB mode is 'n'-bit CFB, where 'n' is
the <A HREF="#block-length" STYLE="symbol">block-length</A> of the cipher)</LI><LI>CFB8 (this seems to be the mode other crypto packages call
'CFB')</LI><LI>CTR</LI></UL><P><EM>mode</EM> should be a symbol in the <TT>KEYWORD</TT> or <TT>IRONCLAD</TT>
