"Encrypted identd responses are now ignored, and such clients will come 
online with the usual ~username field instead.  Some distributions of 
linux come with pidentd encryption enabled, and the resulting idents 
are too long to be useful on IRC (they showed up as [U2FsdGVkX etc).  
The box admin would need the entire 34 character ident to figure out 
what user it is, assuming it's a valid shell account in the first 
place.  When this happens, the server says "*** Ignoring 
encrypted/unusable Ident response" on connect."

Second email:
"I've just discovered there's a second encryption format in use, and 
that one isn't blocked."