Now that I've had some time to think about it, the solution which I mentioned should be pretty simple to implement and I will definitely have it done before I can get my hands on ASIC hardware. When the client starts up, if there is a Bitcoin wallet, it will open the wallet in read-only mode and for each of the Bitcoin addresses it will generate a new public/private key pair address first using a yet to be determined cryptographic algorithm, which may either be the same ECDSA algorithm that Bitcoin uses or a different cryptographic algorithm that will produce the same length address and then afterwards it will sign the transaction again using the original Bitcoin private key. The order is critical to guarantee that when the currency is eventually sent, the transactions will not be incompatible with Bitcoin. Afterwards the client could either continue to use twice signed addresses or just use single signed addresses. Please let me know if you have a recommendation for which cryptographic algorithm I should use or if you know or if you can think of a more elegant solution. Thanks!