Re: [bitcoin-dev] [BIP Proposal] Partially Signed Bitcoin Transaction (PSBT) format

2017-08-22 Thread Greg Sanders via bitcoin-dev
If 'x' is public, that makes it identifiable and privacy-losing across inputs. To avoid "re-use" I suppose you'd want to sign some message like `HMAC("ownership proof", H(A || x) )` instead. Otherwise any signature you make using `A` ends up being used as a proof you don't know the input(this

Re: [bitcoin-dev] [BIP Proposal] Partially Signed Bitcoin Transaction (PSBT) format

2017-08-21 Thread Jochen Hoenicke via bitcoin-dev
On 21.08.2017 20:12, Greg Sanders via bitcoin-dev wrote: > To fix this I consulted with andytoshi and got something we think works > for both cases: > > 1) When a signing device receives a partially signed transaction, all > inputs must come with a ownership proof: > - For the input at address A,

Re: [bitcoin-dev] [BIP Proposal] Partially Signed Bitcoin Transaction (PSBT) format

2017-08-21 Thread Greg Sanders via bitcoin-dev
Some related thoughts and suggestion for an extension that kanzure suggested I post here: Hardware Wallet attacks by input ownership omission and fix -- So a while back I realized that to have HW wallets do safe

Re: [bitcoin-dev] [BIP Proposal] Partially Signed Bitcoin Transaction (PSBT) format

2017-08-20 Thread Bryan Bishop via bitcoin-dev
On Fri, Aug 18, 2017 at 5:11 PM, Andrew Chow via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > > I would like to propose a standard format for unsigned and partially > signed transactions. > Just a quick note but perhaps you and other readers would find this thread (on hardware

[bitcoin-dev] [BIP Proposal] Partially Signed Bitcoin Transaction (PSBT) format

2017-08-18 Thread Andrew Chow via bitcoin-dev
Hi everyone, I would like to propose a standard format for unsigned and partially signed transactions. ===Abstract=== This document proposes a binary transaction format which contains the information necessary for a signer to produce signatures for the transaction and holds the signatures for