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 Introduction
Using the utility
 
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Data Wiper
Wipe out confidential data
 
by Giovanni B. Perotti (Italy)
Your highly condidential data may not need to permanently reside on your system. For security reason, you may need to save them to some offline media, delete them from disk and restore them when needed.
However, your data files, though "deleted", remain for some time in unallocated disk areas and there are ways they could still be read. How can you make them truly unreadable?

1-About it

When you delete any DASD data set or release part of the space, the system makes the space available for allocation for new data sets.
There are ways that the creator of the new data set can read residual data that was in the previous data set.
To prevent others from reading your deleted data, you may run a program that overwrites the data before you delete it.

Our DataWiper utility provides a command to overwrite physical files, thus making them unreadable.
You may use this command after saving your files and before deleting them. Though they may stay for some time in the unallocated disk space, they would no longer contain confidential data.

2-Prerequisites

  • IBMi OS release V5R3 or any subsequent one
  • Library QHTTPSVR, product 57xx-DG1
  • Compiler ILE RPG IV, product 57xxWDS, opt. 31
Once installed, you may remove its sources, save and restore it to another IBMi partition.

3-Installation

  • Download file DATAWIPER.zip from the Easy400 download page and unzip it.
  • Follow the DATAWIPER.txt instructions to upload and to restore library DATAWIPER.
  • On the IBMi, sign on with a class *SECOFR user profile and run the following procedure:
    STRREXPRC SRCMBR(INSTALL) SRCFILE(DATAWIPER/QREXSRC) .
    It does the following:
    • creates objects in library DATAWIPER
    • restores IFS directory /datawiper, which includes this manual both in HTML and in PDF format
    • creates a local data library named DATAWIPLCL
    • revokes public access from the utility objects, so that only a class *QSECOFR user profile may access them.

4-Post-installation warning

An uncontrolled use of this tool may result in some unrecoverable dataloss.
You are therefore strongly suggested to implement the following preventative measures:
  1. (minimum) - Remove from library DATAWIPER its 7 source files (QCLSRC, QCMDSRC, QDDSSRC, QPNLSRC, QREXSRC, QRPGLESRC, QSRVSRC) in order to protect utility objects from malicious changes.
    This can be easily done with command DATAWIPER/EXPSRCF. This command moves those source files to a user specified library, that you may then save and delete.
    Should you ever need to bring back those source files, just restore your user library and run command DATAWIPER/IMPSRCF. This command duplicates the source files to library DATAWIPER.
  2. (best) - Save library DATAWIPER to some offline media and lock it away. Then delete library DATAWIPER from your system.
    Restore library DATAWIPER for some just temporary use under your full control.

5-Maintenance

This utility is maintained on request, both for applying fixes and for adding enhancements.
Send your requests to the author. To know what is new, just take a look at its Change Log.