Multisignature for bip-schnorr

Multisignature for bip-schnorr
2018-08-29 11:28 ` Erik Aronesty
                   ` (2 more replies)
  
From: nakagat @ 2018-08-07  6:35 UTC (permalink / raw)
  To: bitcoin-dev

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


 permalink raw reply	[|nested]
2018-08-29 11:28 ` 
                   ` 
  
From: nakagat @ 2018-08-07  6:35 UTC (permalink / raw)
  To: bitcoin-dev

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


 permalink raw reply	[|nested]
2018-08-07  6:35 [bitcoin-dev] Multisignature for bip-schnorr nakagat
  2018-08-29 11:28 ` Erik Aronesty

  2018-09-07  8:11 ` Jonas Nick
  
From: nakagat @ 2018-08-31  5:22 UTC (permalink / raw)
  To: 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

Original
https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki#Multisignatures_and_Threshold_Signatures

-- 
nakagawa

2018年8月7日(火) 15:35 nakagat <nakagat@gmail•com>:
>
> 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


 permalink raw reply	[|nested]
2018-08-07  6:35 [bitcoin-dev] Multisignature for bip-schnorr nakagat
  2018-08-29 11:28 ` Erik Aronesty
  2018-08-31  5:22 ` nakagat

  2018-09-12  6:00   ` nakagat
  
From: Jonas Nick @ 2018-09-07  8:11 UTC (permalink / raw)
  To: nakagat, Bitcoin Protocol Discussion

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
> 


 permalink raw reply	[|nested]
2018-09-07  8:11 ` Jonas Nick

  
From: nakagat @ 2018-09-12  6:00 UTC (permalink / raw)
  To: jonasdnick;  bitcoin-dev

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>:
>
> 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
> >


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