Multisignature for bip-schnorr
5 messages, 7 Aug to 12 Sep 2018. Started by nakagat.
nakagat (3), Erik Aronesty, Jonas Nick
Hi all,
I wrote a multisignature procedure using bip-schnorr.
If you have time to review and give feedback, I’d really appreciate it. Thanks in advance!
Multisignature https://gist.github.com/tnakagawa/0c3bc74a9a44bd26af9b9248dfbe598b
It's cool but
- there's a lot of online steps. - it's not a threshold system
Using a shamir scheme solves this and isn't subject to birthday attacks:
https://medium.com/@simulx/an-m-of-n-bitcoin-multisig-scheme-e7860ab34e7f
On Mon, Aug 13, 2018 at 7:08 AM nakagat via bitcoin-dev < bitcoin-dev@lists•linuxfoundation•org> wrote:
Quoted text (21 lines)
> Hi all, > > I wrote a multisignature procedure using bip-schnorr. > > If you have time to review and give feedback, I’d really appreciate it. > Thanks in advance! > > Multisignature > https://gist.github.com/tnakagawa/0c3bc74a9a44bd26af9b9248dfbe598b > > Original > > https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki#Multisignatures_and_Threshold_Signatures > > -- > nakagawa > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation•org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >
Hi all,
I wrote t-of-k threshold signature procedure using bip-schnorr.
If you have time to review and give feedback, I’d really appreciate it. Thanks in advance!
Threshold Signatures https://gist.github.com/tnakagawa/e6cec9a89f698997dc58a09db541e1eb
Your multisignature writeup appears to be vulnerable to key cancellation attacks because the aggregated public key is just the sum of public keys (and there is no proof of knowledge of the individual secret keys). Therefore, in a multisignature between Alice and an attacker, the attacker can choose their key to be -alice_key+attacker_key resulting in an aggregated key for which the attacker can sign alone (without requiring Alice's partial signature). The Schnorr BIP links to the MuSig paper which describes a secure key aggregation scheme. See https://eprint.iacr.org/2018/068
On 8/7/18 6:35 AM, nakagat via bitcoin-dev wrote:
Quoted text (13 lines)
> Hi all, > > I wrote a multisignature procedure using bip-schnorr. > > If you have time to review and give feedback, I’d really appreciate it. > Thanks in advance! > > Multisignature > https://gist.github.com/tnakagawa/0c3bc74a9a44bd26af9b9248dfbe598b > > Original > https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki#Multisignatures_and_Threshold_Signatures >
Hi Jonas
Thank you for your comment.
I wrote a new text. https://gist.github.com/tnakagawa/e6cec9a89f698997dc58a09db541e1eb
If you have time, please review this. 2018年9月7日(金) 17:09 Jonas Nick <jonasdnick@gmail•com>:
Quoted text (24 lines)
> > Your multisignature writeup appears to be vulnerable to key cancellation > attacks because the aggregated public key is just the sum of public keys (and > there is no proof of knowledge of the individual secret keys). Therefore, in a > multisignature between Alice and an attacker, the attacker can choose their key > to be -alice_key+attacker_key resulting in an aggregated key for which the > attacker can sign alone (without requiring Alice's partial signature). The > Schnorr BIP links to the MuSig paper which describes a secure key aggregation > scheme. See https://eprint.iacr.org/2018/068 > > On 8/7/18 6:35 AM, nakagat via bitcoin-dev wrote: > > Hi all, > > > > I wrote a multisignature procedure using bip-schnorr. > > > > If you have time to review and give feedback, I’d really appreciate it. > > Thanks in advance! > > > > Multisignature > > https://gist.github.com/tnakagawa/0c3bc74a9a44bd26af9b9248dfbe598b > > > > Original > > https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki#Multisignatures_and_Threshold_Signatures > >