⚠️Nostr practical security — attack vulnerabilities ⚠️

Researchers’ quote:

" Our results on Nostr show that their use of cryptographic technologies is simple and immature, showing a sharp difference from the modern messaging applications that the research community has scrutinised.

We think there is a significant lack of understanding on the secure design and analysis of distributed SNSs: what security property should be set, and what about the security of popular growing services other than Nostr, such as Mastodon and BlueSky? "

A new research paper (Aug 2025) analysed Nostr and found basic cryptographic and design weaknesses that allow attackers to abuse the protocol in ways that real users and services should be concerned about.

👉In plain terms:

attackers can trick clients and servers, steal funds or impersonate users in practical scenarios unless fixes are applied.

👉Key impacts everyone must know

1) Financial risk — attackers can hijack or manipulate keys or requests, causing loss of funds (wallet integrations, invoice relays, LN payflows).

2) Account and reputation risk — impersonation and message forgery can damage user identity, enable scams, or undermine trust models.

3) Ecosystem availability and privacy risk — attacks can de-anonymise users or flood/poison relays, degrading service and exposing metadata.

👉Call to action for developers and users

- Developers: audit signing and verification flows, wallet integrations, relay filtering and threat models; prioritise fixes for key handling and message-authentication weaknesses.

- Users: assume higher risk for money-related actions; avoid new integrations until maintainers publish mitigations; verify payments and identity out-of-band.

Looping in relevant parties below. Regardless of whether the source is trustworthy, the attacks described are worth investigating.