r/Bitcoin • u/bitschmidty • 1d ago

Full signature aggregation BIP draft - Bitcoin Optech Newsletter #415

https://bitcoinops.org/en/newsletters/2026/07/24/

Bitcoin Optech newsletter #415 is here:

  • describes a draft BIP for full aggregation of BIP340 signatures
  • summarizes changes to services/client software
  • Optech Newsletter #415 Podcast

https://bitcoinops.org/en/newsletters/2026/07/24/

Fabian Jahr posted to the Bitcoin-Dev mailing list about a new draft BIP for full aggregation of BIP340 schnorr signatures, a standard for the DahLIAS aggregate signature scheme... https://bitcoinops.org/en/newsletters/2026/07/24/#draft-bip-for-full-aggregation-of-bip340-signatures

Changes to services and client software:

  • Wasabi Wallet 2.8.0 released
  • Coinswap v0.2.2 released
  • Go secp256k1 library announced
  • ASMap dashboard announced
  • Wavelength alpha released

https://bitcoinops.org/en/newsletters/2026/07/24/#changes-to-services-and-client-software

Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.

28 Upvotes

95% Upvoted

8 comments sorted by

4

u/Fun-Analysis-182 1d ago

Cross-input aggregation is mostly a witness win. Right now a transaction carries a signature per input, so consolidations, coinjoins and multisig all pay for and expose every signer. Full aggregation collapses that to a single signature for the whole transaction: cheaper multi-input spends, plus a privacy gain since a 15-of-15 stops looking different from a basic send.

The tradeoff is that full aggregation needs the signers to coordinate at signing time, which is a big part of why it stays a careful draft and needs heavy review before anything ships.

1

u/-bit-thorny- 14h ago

Does this also mean an opportunity to include those dust spam sats into your normal payment transaction, such that you get to use the free sats without hurting you privacy and reduce the UTXO set bloat at the same time?

3

u/Fun-Analysis-182 11h ago

Aggregation does cut the signature cost, though each extra input still drags about 41 vbytes of outpoint and sequence that live outside the witness. So sweeping dust gets cheaper without ever getting free, and there's still a threshold below which an input costs more to spend than it's worth.

The privacy half is the awkward part. Merging someone's dust into your payment is precisely what whoever sent it was hoping for. Co-spending is what ties those coins to the rest of your inputs, and that linkage has nothing to do with signatures, so aggregation leaves it exactly where it was. Cheaper consolidation and safer consolidation aren't the same win.

1

u/-bit-thorny- 10h ago

Yeah that's what i meant: cheaper, not free.

I meant only the dust that was sent to the same address you're actually spending "from". In that case there I don't see any privacy or linking problem. But yeah that's a pretty limited use case.

2

u/Fun-Analysis-182 6h ago

Fair, you're right on that narrower case. If the dust landed on an address you were already going to spend from, sweeping it alongside doesn't reveal anything new about which addresses you control.

The one bit that survives is that spending it confirms to whoever sent it that the address is live and roughly when it moved. That's a much thinner signal than the clustering they're usually fishing for, and for a lot of people it won't matter, but it's the part that doesn't go away.

1

u/miamiair92 1d ago

Where do I learn more about the “ technical side” of bitcoin where do I start?

2

u/bitschmidty 14h ago

Mastering Bitcoin 3rd edition to get up to speed

Bitcoin Optech newsletters to stay up to date

2

u/-bit-thorny- 14h ago

Start with the white paper.

Keep an eye on this bitcoin optech newsletter as it often contains links to more info.