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

In this week update we feature a security patch released by Fedimint to fix several vulnerabilities in the federated ecash protocol. No funds were lost, nor any federation was affected.

We also cover several important news from the Bitcoin ecosystem. We discuss first stable release of Payjoin, the Boltz team stepping down, a new library for SHRINCS, and a new Bitcoin node implementation in Rust, rbitcoin.

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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:

• Fedimint released a security patch on August 13th which fixes several vulnerabilities on the federated ecash protocol.
  • During the weekly call, on Monday 10th, Fedimint contributors discussed a security patch applied to fix some vulnerabilities. The patch was backported to previous versions and two new releases, v0.10.1 and v0.11.2, were published soon after.
  • According to the Fedimint team, the vulnerabilities were responsibly disclosed by the Red Team and Loupe. Devs contacted all known federations and had all of them upgrade to the new patched version. No funds were lost, nor any federation was affected.
  • The security patch fixes around 30 small vulnerabilities. According to PR8997, the various issues can fall in different categories, such as contract funding and claiming on the LNv1/LNv2 modules, consensus version gating, panic containment, gateway module correctness, and wallet module.

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A BIPs Update

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

Numbered BIPs#

A list of BIPs that recently got assigned a number

BIP461: Deterministic ECDSA Signatures#

Assigned On: Aug 13th, 2026

Layer: Applications

PR2224 introduces BIP461, which defines how to obtain deterministic ECDSA signatures. A signature is now encoded using the Distinguish Encoding Rule (DER), which results in two numbers r and s , treated as big-endian signed integers. Due to the sign, in case a r number has its most significant bit set to 1 , hence treated as negative, a null byte is added to keep it positive. BIP461 describes how to do low r grinding of an ECDSA signature, to avoid adding an additional byte to it. The described process is deterministic, following RFC6979.

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Other News from the Bitcoin World

• Stable Payjoin: On August 12th, Payjoin contributors announced the release of the first stable version of the payment batching protocol, v1.0.0.

  • The release includes support for both the legacy Payjoin, described in BIP78, and the most recent asynchronous version, defined in BIP77.
  • The Rust crate comes also with UniFFI bindings for several programming languages, such as Python, Dart, C#, and JavaScript.
  • The first stable release comes after more than three years of development and integration with several wallets.

• The Boltz team steps down: On August 12th, Boltz announced that the whole founders team had step down from the company.

  • In the X post, the team explained that the decision was taken due to the impossibility “to withstand the current level of attacks in the long run,” given the limited resources with which they have been operating over the years.
  • According to the team, a new group of veteran bitcoiners is taking on Boltz. The identities of the new team have not been revealed yet.

• A library for SHRINC: Blockstream’s Head of Research Jonas Nick announced the release of libshrincs, a hand-written and formally-verified C implementation of WOTS+C , the one-time signature scheme used by SHRINCS.

• A Rust Bitcoin Node: Rearden announced on X that he has been working on a new Bitcoin node implementation in Rust, called rbitcoin. While it is not deemed production ready yet, it already supports Electrum, Esplora, and core RPC interfaces.

• Listen to the Insider: The Insider Edition now has a dedicated podcast feed where you can listen to our audio-only interviews. Check it out!

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Looking for an opportunity to join up with some bitcoin devs in person? Join us in Berlin this October 1- 3 to talk about payments in Bitcoin!