fmsg, an open distributed messaging protocol and its Go implementation (fmsgd).

This protocol addresses fundamental security and integrity gaps inherent in legacy messaging systems like email. The market demand for verifiable, tamper-proof communication is increasing, driven by regulatory compliance and rising cyber threats. By integrating cryptographic hashes and DAG structures, fmsg offers a robust foundation for secure B2B communication. Its distributed nature and self-hosting capability reduce vendor lock-in and enhance data sovereignty, critical for enterprise adoption. The "out-of-the-box" security features simplify deployment compared to complex email authentication configurations. This could disrupt sectors reliant on secure, auditable message exchange, provided it achieves sufficient network effect and client tooling. The Go implementation and Docker setup lower initial friction for developers.