Bitcoin Forum
May 25, 2019, 02:34:26 AM *
News: Latest Bitcoin Core release: 0.18.0 [Torrent] (New!)
 
   Home   Help Search Login Register More  
Pages: [1]
  Print  
Author Topic: Signing a sum of bitcoin  (Read 126 times)
cellard
Legendary
*
Offline Offline

Activity: 1372
Merit: 1209


View Profile
October 05, 2018, 07:47:50 PM
Merited by bones261 (2)
 #1

Is it possible to somehow get a sum of a bunch of different inputs and then generate a single resulting signature that could prove you own for instance 1 BTC? Or it's impossible and you must go through the hassle of signing a bunch of different inputs that make a sum of 1 BTC and the person must manually verify and sum it all? This beside being annoying and slow, goes against your privacy interests as you show a ton of different inputs.

Ideally, it would be cool to do it with a single click. If the wallet contains +1 BTC, then generate a single hash that proves this somehow. For example I like to think that in 2030 or so, there will be clubs in which you cannot access if you don't own 1+ BTC, then you bring this signature with you like a VIP pass, bouncer verifies it and you are in. I think this may be impossible but just asking if it could somehow be made.
1558751666
Hero Member
*
Offline Offline

Posts: 1558751666

View Profile Personal Message (Offline)

Ignore
1558751666
Reply with quote  #2

1558751666
Report to moderator
1558751666
Hero Member
*
Offline Offline

Posts: 1558751666

View Profile Personal Message (Offline)

Ignore
1558751666
Reply with quote  #2

1558751666
Report to moderator
GET 25 FREE SPINS AT REGISTRATION
GET 100% BONUS ON FIRST DEPOSIT
PLAY NOW
Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.
1558751666
Hero Member
*
Offline Offline

Posts: 1558751666

View Profile Personal Message (Offline)

Ignore
1558751666
Reply with quote  #2

1558751666
Report to moderator
HCP
Legendary
*
Offline Offline

Activity: 980
Merit: 1508

<insert witty quote here>


View Profile
October 05, 2018, 10:02:58 PM
Merited by bones261 (2)
 #2

This BIP seems like it might be addressing this general scenario amongst several others: https://github.com/bitcoin/bips/blob/master/bip-0322.mediawiki#Multiple_Proofs

However, it seems that it will still "expose" all the UTXOs required to make up the sum, as opposed to just proving a sum total.

Thirdspace
Hero Member
*****
Offline Offline

Activity: 994
Merit: 653


Mixing reinvented for your privacy | chipmixer.com


View Profile
October 05, 2018, 10:29:26 PM
 #3

Is it possible to somehow get a sum of a bunch of different inputs and then generate a single resulting signature that could prove you own for instance 1 BTC?
I don't think it is possible because signing requires a private key of a public address
so even if there is a way to sign sum of multi inputs, to verify it people will (need to) know all input addresses
why didn't you consolidate your utxo and have your bitcoin in one address?

cellard
Legendary
*
Offline Offline

Activity: 1372
Merit: 1209


View Profile
October 06, 2018, 01:06:15 AM
 #4

Is it possible to somehow get a sum of a bunch of different inputs and then generate a single resulting signature that could prove you own for instance 1 BTC?
I don't think it is possible because signing requires a private key of a public address
so even if there is a way to sign sum of multi inputs, to verify it people will (need to) know all input addresses
why didn't you consolidate your utxo and have your bitcoin in one address?

This would require you to spend money into fees to do that. While it may be affordable now, it may not be economically sound in the future, just to present some cryptographic proof, unless you really need to. Also like I said before, consolidating it all into a single address can break privacy sometimes.
Coding Enthusiast
Hero Member
*****
Offline Offline

Activity: 625
Merit: 851


Novice C♯ Coder


View Profile WWW
October 06, 2018, 04:05:10 AM
Merited by bones261 (2), ETFbitcoin (1)
 #5

If you want to define something that does not exist then you also have to define a standard for it too. For example in this case you can define it like this:
1. Append all the transaction outputs you want to sign together. (Lets assume it is 5 UTXO belonging to 3 keys). Put transactions that belong to one key together and the order is important.
Code:
[Tx1_key1][Tx2_key1][Tx3_key2][Tx4_key3][Tx5_key3]
Perform a SHA256 on the whole thing to make it 32 bytes.
2. Sign with key1, key2, key3 and then concatenate 3 resulting signatures together. You can DER encode it if you like:
Code:
[Seq][size]
  [Seq][size][int][size][r][int][size][s]
  [Seq][size][int][size][r][int][size][s]
  [Seq][size][int][size][r][int][size][s]
* Seq and int are DER flags.
** There is an additional part in signatures for recovering public key that I am not familiar with yet but assume we added that to the signature Tongue

Projects List+Suggestion box
Donation link using BIP21
Bech32 Donation link!
BitcoinTransactionTool (0.9.2):  Ann - Source Code
Watch Only Bitcoin Wallet (supporting SegWit) (3.1.0):  Ann - Source Code
SharpPusher (broadcast transactions) (0.10.0): Ann - Source Code

bones261
Legendary
*
Offline Offline

Activity: 1568
Merit: 1539


My hat is in storage. https://ibb.co/YLkPgXb


View Profile
October 06, 2018, 03:35:26 PM
 #6

Won't Schnorr signatures pave the way to make this possible? (When and if it gets integrated.)

......
.L I V E C O I N . N E T.
.
..PROFITBOX..
██  █████████████████████████
  █████████▄      ▄██████████
█████████████▄  ▄████████████
    █████████████████████████
  ██████████▀    ▀█ ▀████████
████  █████▀  ▄▄  ▀█  ▀██████
  ████████▀  ▄██▄  ▀█   ▀████
    ██████   ▀██▀   ██   ████
  █████████▄      ▄██████████
██  █████████▄  ▄████████████
  ███████████████████████████
██  █████████████████████████
  █████████████████████▀ ███
█████████████████████▀   ███
    █████████████▀     ████
  █████████████▀   ██    ████
████  █████▀     ██    ████
  ███████▀   ██    ██    ████
    █████    ██    ██    ████
  ███████    ██    ██    ████
██  █████    ██    ██    ████
  ███████████████████████████
.....
Pages: [1]
  Print  
 
Jump to:  

Sponsored by , a Bitcoin-accepting VPN.
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!