In order to simplify our TLS implementation and as part of our support for strong encryption for everyone, we are pleased to announce availability of a new Open Source implementation of the TLS protocol: s2n.  s2n is a library that has been designed to be small, fast, with simplicity as a priority. s2n avoids implementing rarely used options and extensions, and today is just more than 6,000 lines of code. As a result of this, we’ve found that it is easier to review s2n; we have already completed three external security evaluations and penetration tests on s2n, a practice we will be continuing.

Source: Introducing s2n, a New Open Source TLS Implementation – AWS Security Blog

If you are interested in using or contributing to s2n, the source code, documentation, commits and enhancements are all publically available under the terms of the Apache Software License 2.0 from the s2n GitHub repository.