LibreSSL is described as 'version of the TLS/crypto stack forked from OpenSSL in 2014, with goals of modernizing the codebase, improving security, and applying best practice development processes' and is an app in the Security & Privacy category. There are five alternatives to LibreSSL for a variety of platforms, including Windows, Linux, Mac, BSD and Android. The best alternative is OpenSSL, which is both free and Open Source. Other great apps like LibreSSL are GnuTLS (Free, Open Source), mbed TLS (Free), wolfSSL (Free, Open Source) and SharkSSL (Free Personal).
mbed TLS (formerly known as PolarSSL) makes it trivially easy for developers to include cryptographic and SSL/TLS capabilities in their (embedded) products, facilitating this functionality with a minimal coding footprint.
The SSL/TLS and Certificate tutorial for Windows enables you to fast track your understanding of the SSL/TLS protocol, Certificate Management, and secure communication. The download includes many C source code examples, including a secure WebSocket tutorial.