OpenSSL

OpenSSL is an open-source software library that provides a robust, full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It's widely used to secure communications over computer networks and for encrypting sensitive data.

OpenSSL supports various encryption algorithms, allowing for both symmetric (e.g., AES, DES) and asymmetric (e.g., RSA, ECC) encryption. This makes it suitable for a range of security needs, from encrypting data in transit to securing files on disk.

It offers comprehensive support for SSL and TLS protocols, essential for secure communication over the internet, like in HTTPS. OpenSSL can create and manage SSL/TLS certificates. It's often used for generating private keys, creating Certificate Signing Requests (CSRs), and managing certificate authorities (CAs).

It includes a library of cryptographic functions, such as hashing, digital signatures, and random number generation.

It is used to implement SSL/TLS for securing websites, particularly in popular web servers like Apache and Nginx. Developers use OpenSSL in a variety of programming languages to add encryption and secure communication capabilities to their applications.

OpenSSL also provides a powerful command-line tool for performing a multitude of cryptographic operations, such as encrypting/decrypting files, managing SSL/TLS certificates, and testing SSL/TLS connections.