The OpenSSL Project is an effort to develop an open-source toolkit that implements the SSL and TLS protocols, as well as a cryptographic library.
The available commands of the openssl tool include the following:
The pkcs12 command parses or generates a PKCS #12 file.
The req command creates and processes certificate requests in PKCS #10 format.
You can download the current version of OpenSSL at http://www.openssl.org.