$ sudo apt-get install openssl  
$ openssl version
$ openssl enc -aes-256-cbc -in message.txt -out message.bin 
$ ls -ltr
$ openssl enc -base64 -in message.bin -out message.b64
$ ls -ltr
$ cat message.b64
$ openssl enc -d -aes-256-cbc -in message.bin -out message.dec
$ cat message.dec 
$ openssl enc -d -base64 -in message.b64 -out message.ptx
$ ls -ltr
$ cat message.ptx