Using the OpenSSL toolkit with Bash
Cryptography is an important part of IT security, and OpenSSL is a well-known cryptography toolkit for Linux. Experts depend on OpenSSL because it is free, it has huge capabilities, and it’s easy to use in Bash scripts.
OpenSSL makes use of standard input and standard output, and it supports a wide range of parameters, such as commandline switches, environment variables, named pipes, file descriptors, and files. You can take advantage of these features to quickly write Bash (Bourne-Again Shell) scripts that automate tasks, such as testing SSL/ TLS (Secure Socket Layer/Transport Layer Security) connections, bulk conversions between different formats of cryptographic keys and certificates, batch signing/ encrypting of files, auditing password protected files, and implementing or testing a PKI (Public Key Infrastructure).
The OpenSSL toolkit provides many modules that each perform a specific task. Each module is not a separate executable, but is, instead, selected with the first parameter of the openssl executable. On the other hand, each module has a separate manual page. For example, a module named x509 manages X.509 digital certificates and a module named pkcs12 manages PKCS12 packages.