Encrypt and decrypt files

Examples:

openssl enc, openssl enc -d
ansible-vault encrypt, ansible-vault decrypt
sops -d, sops -e

Using OpenSSL[edit]

Encrypt and decrypt a file^[1] (GPG can also be used for encrypting and decrypting files)
Using aes-256-cbc cypher, You will be prompted for a password when encrypting that has to be used for decrypting.^[2]

Encrypt file (openssl enc):

openssl enc -aes-256-cbc -in un_encrypted.data -out encrypted.data

You can use file command to verify file type.

file encrypted.data
encrypted.data: openssl enc'd data with salted password

Encrypt file providing password on the command line, be aware that your password will be store on history of your shell):

openssl aes-256-cbc -a -salt -in twitterpost.txt -out foo.enc -pass file:<( echo -n "someGoodPassword" )

Decrypt file (openssl enc -d):

openssl enc -d -aes-256-cbc -in encrypted.data -out un_encrypted.data

macOS options:

-salt Use a salt in the key derivation routines (the default). When the salt is being used the first eight bytes of the encrypted data are reserved for the salt: it is randomly generated when encrypting a file and read from the encrypted file when it is decrypted.