









So if we subvert one of the two escrow agents, we only have a 40-bit
space to search through...

2^40 doesn't sound that big - is digital telephony subject to a known
plaintext attack?

In which case half the key seems to be all that is needed, and the two
agent escrow arrangement is pointless. 

Of course, the unknown algorithm might turn gaps in speech into 
pseudo-random sequences, or there might be some magic involved, or...