/ENCRYPT=([key] [,ALGORITHM=algorithm])

    Creates and restores encrypted save sets. Specify the /ENCRYPT
    qualifier anywhere on the BACKUP command line.

                                   NOTE

       Standalone BACKUP, which is a version of the BACKUP utility
       that runs without the support of the OpenVMS operating
       system, does not support the /ENCRYPT qualifier.

    Optionally, you can specify either a key name or a key value, but
    not both. If you have already defined a key value using the DCL
    command ENCRYPT/CREATE_KEY, you can specify /ENCRYPT=NAME=key-
    name to identify the key name that was created and stored in the
    key storage table.

    To define a key value interactively, specify /ENCRYPT=VALUE=key-
    value,
    where key-value is one of the following:

    o  1 to 243 alphanumeric characters enclosed in quotation
       marks (""). Dollar signs ($) and underscores (_) are valid
       characters. The key is not case sensitive.

    o  A hexadecimal constant using the digits 0 to 9 and A to F.

                                   NOTE

       For additional security, specify the /ENCRYPT qualifier with
       no parameters and press Return. The command prompts you for
       a key value. When you enter a value, the software does not
       echo what you type and, for verification, prompts you to
       retype the value.