Encryption techniques are used mainly to protect data from unauthorized access. There are many algorithms available and we have discussed the most commonly used ones. There are a few tools available in a Linux environment for performing encryption and decryption. Sometimes we use encryption algorithm hashes for verifying data integrity. This section will introduce a few commonly used cryptographic tools and a general set of algorithms that these tools can handle.
Let us see how to use tools such as crypt
, gpg
, base64
, md5sum
, sha1sum
, and openssl
:
The
crypt
command is a simple and relatively insecure cryptographic utility that takes a file fromstdin
and a passphrase as input and output encrypted data intostdout
(and, hence, we use redirection for the input and output files):$ crypt <input_file >output_file Enter passphrase:
It will interactively ask for a passphrase. We can also provide a passphrase through command-line arguments:
$ crypt...