The openssl package contains c_rehash, openssl, libcrypto libraries and libssl libraries. c_rehash is a perl script that scans all files in a directory and adds symbolic links to their hash values. The openssl program is a command line tool for using the various cryptography functions of OpenSSL's crypto library from the shell. It can be used for various functions which are documented in man 1 openssl. The OpenSSL crypto library implements a wide range of cryptographic algorithms used in various Internet standards. The services provided by this library are used by the OpenSSL implementations of SSL, TLS and S/MIME, and they have also been used to implement OpenSSH, OpenPGP, and other cryptographic standards. The OpenSSL SSL library implements the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols. It provides a rich API, documentation on which can be found by running man 3 ssl.