Use the following command: 17z a -p -mem=AES256 -tzip file.zip source-file1.txt source-file2.txt It will ask for a password but will obviously not be echoed. To decrypt: 17za e file.zip You need to install as well associated tools. Shown are for Redhat-like Linux: 1sudo yum install p7zip p7zip-plugins Some details …

in /etc/postfix/main.cf, add: 1smtpd_tls_security_level = may 2smtp_tls_security_level = may 3smtp_tls_loglevel = 1 4smtpd_tls_loglevel = 1 Details from From http://blog.snapdragon.cc/2013/07/07/setting-postfix-to-encrypt-all-traffic-when-talking-to-other-mailservers/