On 20 December 2014 at 14:48, Peter Todd <p...@petertodd.org> wrote: > We need the following primitives operating on message m, pubkey p, and a > valid signature sig1 for m, p: > > AntiReplaySign(m, p, sig1) -> sig2 > VerifyAntiReplaySig(m, p, sig2) -> True or False > > Additionally once AntiReplaySign() has been used once for a given pubkey > it is impossible to re-run the primitive on a different message m'. This > is of course impossible to implement with math alone, but we can > implement it with a trusted third party.
Well while you cant prevent it you could render it insecure enabling miners to take funds. That could work via a one-show signature; normal ECDSA being address a=H(Q), public key Q=dG, R=kG, r=R.x, s=(H(m)+rd)/k, signature (r,s), verify: a=?H(Q) and sR=?H(m)G+rQ one-show being: a=H(Q,R), verify being: a=?H(Q,R) and sR=?H(m)G+rQ. Now that is unsafe to double-spend by design as only that specific R is usable and as we know reusing R with different messages leaks the private key because: s=(H(m)+rd)/k and s'=(H(m')+rd)/k implies sk=H(m)+rd and s'k=H(m')+rd so k=(H(m)-H(m'))/(s'-s), and d=(sk-H(m))/r. Adam ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
