Just off the top of my head (I have to check the SSH protocol yet): Why not 
encipher all accumulated keystrokes up to the <Enter> key as a block send them 
instead of sending each keystroke as it is typed? This shrouds the typist's 
characteristics.
In addition, if the cipher is a block cipher, padding is added to make the 
number of bits a multiple of the block size. Mandatory padding with a nonce may 
help to shroud the number of keystrokes.
The drawback is that the padding part could mean that we are no longer 
compatible with the SSH protocol.

Reply via email to