An application I have put a bit of thought into is the idea of creating a distributed banking system. That is not offline, but not a single centralised trusted bank either. Ideally it is a system where all nodes are equivalent, and k of n of those nodes have to collude before they can compromise the operation of the bank. This is related to the encrypted computation idea where I can ask you to perform a computation for me, but you won't know the operands, and I can recover the answer with a final transformation. There are a few such protocols around to compute certain functions. This would be a distributed system, the nodes in the network would be able to simulate a virtual CPU by exchanging messages and computing encrypted functions. The program you run on the virtual CPU is the bank software. One approach would be to simulate the CPU by using the exchange of encrypted communications to simulate circuit functions in the CPU. Hopefully there would be more efficient methods of performing this securely distributed computation. People would trust the bank by virtue of their belief that it would be too difficult for an attacker to compromise or acheive sufficent collusion to overcome the n of k threshold. The bank would live in the network in this virtual CPU. Individual nodes may come and go, yet the secured software entity which is the bank and it's account information would live on. Comments on how feasible it would be to design such a system with current crypto techniques? Adam -- Have *you* exported RSA today? --> http://www.dcs.ex.ac.uk/~aba/rsa/ print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<> )]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`