Road to CISA? — Last Week in Bitcoin (Jul 06 - 12)

Published BIPs

btc_insider_edition

13. Juli 2026July 13, 2026 · 5 Min. Lesezeit5 min read

Hi Insiders. This is Tuma, open-source reporter from the Insider Edition.

In this week update we feature the ongoing effort to migrate LDK from GitHub to a self-hosted instance, after the company banned the Lightning implementation from running CI.

We also cover a new BIP being published, BIP95, which defines a new testnet to replace testnet4, and six new BIPs being assigned a number. In particular, BIP453, provides common terminology for transaction components, BIPs 455, 456, and 457 compose the specifications for the SwiftSync protocol for faster IBD, and BIPs 458 and 459 describe half and full signatureaggregation, an important building block towards CISA.

Finally, we cover some interesting news from the Bitcoin ecosystem. In particular, we present some interviews from Nairobi, mempool(.)space joining the SV2 working group, and some useful information about how to protect yourself during the upcoming forks.

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Highlights from the bitcoin developer ecosystem

I spent 10+ hours in open-source developer calls in the Bitcoin ecosystem last week. Here is what caught my eye:


A BIPs Update

In the last days there was some movement in the BIP repository. Specifically, one new BIP has been published and six new BIPs have been assigned a number by BIP maintainer Murchandamus.

Published BIPs#

A list of recently published BIPs

BIP95: Testnet 5#

Published On: Jun 25th, 2026

Layer: Applications

BIP95 defines a new testnet to replace the current testnet4. The new testnet removes the difficulty exception defined in the previous iteration, due to its sustained exploitation that has historically made testing difficult. Moreover, testnet5 raises the minimum difficulty and enforces the consensus rules specified in BIP54 from block 1

Numbered BIPs#

A list of BIPs that recently got assigned a number

BIP453: Terminology of Transaction Components#

Assigned On: Jun 20th, 2026

Type: Informational

PR2195 introduces BIP453, an informational BIP that aims to provide a common terminology for transaction components to be used in Bitcoin-related technical writing and future BIPs.

BIP455: Peer sharing of block spent coins#

Assigned On: Jun 22th, 2026

Layer: Peer Services

PR2152 introduces BIP455, the first BIP that composes the specifications for SwiftSync, a protocol for clients to parallelize initial block download (IBD). BIP455 defines how additional data can be shared over the P2P network to allow a client to validate blocks in arbitrary order.

BIP456: Hints for unspent coins#

Assigned On: Jun 22th, 2026

Layer: Peer Services

PR2152 introduces BIP456, the second BIP that composes the specifications for SwiftSync. BIP456 defines a representation of the UTXO set to be used as “hint” to verify the correctness of the set of unspent coins that a client arrived at through SwiftSync.

BIP457: SwiftSync initial block download#

Assigned On: Jun 22th, 2026

Layer: Applications

PR2152 introduces BIP457, the main BIP that composes the specifications for SwiftSync. BIP457 describes the different components of the protocol and the way it tries to achieve faster IBD through parallelization.

BIP458: Half-Aggregation of BIP 340 Signatures#

Assigned On: Jul 2nd, 2026

Layer: Applications

PR2205 introduces BIP458, which describes how to perform half-aggregation of Schnorr signatures, as per BIP340. Half-aggregation is a non-interactive process for aggregating a collection of signatures into a single signature, whose size is approximately half of the combined size of the original signatures. This approach could also be leveraged for signatures in the inputs of Bitcoin transactions, a process known as cross-input signature aggregation (CISA).

BIP459: Full-Aggregation of BIP 340 Signatures#

Assigned On: Jul 10th, 2026

Layer: Applications

PR2210 introduces BIP459, which describes full-aggregation of Schnorr signatures, as per BIP340, a standard for Discrete Logarithm-Based Interactive Aggregate Signatures (DahLIAS) interactive aggregate signature scheme. Full-aggregation is an interactive process for aggregating a certain number of signatures into a single one, whose final size is the same as a single BIP 340 signature (64 bytes), regardless of the number of signers.

One of the most interesting applications of this BIP is CISA. However, the author notes that this would require a consensus change, which is outside of the scope of this proposal.


Other News from the Bitcoin World


Looking for an opportunity to join up with some bitcoin devs in person? Join us in Toronto this July 22- 24 to talk about finding consensus in Bitcoin!

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Contents

3 sections

  1. Published BIPs
  2. Numbered BIPs