I suspect that skype's motivation is more that it charges for calls out to a landline and for calls in. It uses these profits to pay for the free skype-skype se

I suspect that skype's motivation is more that it charges for calls out to a landline and for calls in. It uses these profits to pay for the free skype-skype service. If I could access the skype protocol I could route all my phone calls over skype->landline and not pay them. Unless of course they actually implemented the security system properly and have a secure method for identifying each end of the call - but they wouldn't have needed to do that because it's all secret.