License Update: UltrafastSecp256k1 → MIT

The initial licensing under AGPL, while protective of open-source contributions, was identified as a barrier to its utilization in key areas such as Bitcoin Core, Lightning networks, nodes, and various research projects. The move to MIT licensing is a strategic alignment with the predominant standards within the ecosystem, aiming to reduce legal uncertainties and enable wider experimentation and use of the library.

UltrafastSecp256k1 has been developed with a focus on high performance, correctness, and broad compatibility. It is designed as a zero-dependency solution that can be ported across different hardware platforms including CPUs, GPUs, MCUs, and SBCs, offering a unified API for all platforms. This approach underscores the project's commitment to delivering a versatile secp256k1 engine that supports extensive experimentation and application without compromising on performance or correctness.

In addition to licensing changes, the project continues to evolve with the latest release, UltrafastSecp256k1 v3.21, emphasizing enhancements in security and efficiency. This version introduces constant-time hardening alongside improvements in SafeGCD scalar inversion and signing performance, further solidifying the library's foundation in providing secure and high-performing cryptographic functionalities. For more details, interested parties can explore the project's repository available at GitHub.

These developments reflect a responsive approach to community feedback, underscoring a commitment to both innovation and alignment with the broader Bitcoin development community's norms and expectations.