read up...
http://www.oxid.it/ca_um/topics/abel.htm
"Abel communicates with Cain using a the Windows named pipe "\\computername\pipe\abel" and it can accept connections from multiple hosts at the same time. All data transmitted over this pipe is encrypted using the RC4 symmetric encryption algorithm and the fixed key "Cain & Abel". This is done only to scramble the traffic sent on the network and not to hide program's intentions."
...user manual
http://www.oxid.it/ca_um/