Cryptographic Vulnerabilities in the Protocol
A 2025 academic study identified practical cryptographic flaws in the Nostr protocol and its implementations. These vulnerabilities allow a malicious user or relay to conduct active attacks, including the forgery of certain message types and, under specific conditions, even breaching the confidentiality of encrypted direct messages. This directly contradicts the security and robustness claims often associated with the protocol, revealing a dangerous gap between the theoretical ideal and the practical implementation.