Re: GNU/Linux is Best for Secure File Deletion

On 4/14/2024 6:26 AM, Lazy Larry Piet wrote:

On Sat, 13 Apr 2024 23:27:15 -0000 (UTC), vallor wrote:
 

>
SHRED(1)                 User Commands                 SHRED(1)
>
NAME
        shred  -  overwrite a file to hide its contents, and op‐
        tionally delete it
>
SYNOPSIS
        shred [OPTION]... FILE...
>
DESCRIPTION
        Overwrite the specified FILE(s) repeatedly, in order  to
        make  it harder for even very expensive hardware probing
        to recover the data.
>

 srm is much better:
 DESCRIPTION
        srm  is  designed to delete data on mediums in a secure manner which can not be recovered by
        thiefs, law enforcement or other threats.  The wipe algorythm is based on the paper  "Secure
        Deletion  of Data from Magnetic and Solid-State Memory" presented at the 6th Usenix Security
        Symposium by Peter Gutmann, one of the leading civilian cryptographers.
         The secure data deletion process of srm goes like this:
         *      1 pass with 0xff
         *      5 random passes. /dev/urandom is used for a secure RNG if available.
         *      27 passes with special values defined by Peter Gutmann.
         *      5 random passes. /dev/urandom is used for a secure RNG if available.
         *      Rename the file to a random value
         *      Truncate the file
         As an additional measure of security, the file is opened in O_SYNC mode and after each  pass
        an fsync() call is done.  srm writes 32k blocks for the purpose of speed, filling buffers of
        disk caches to force them to flush and overwriting old data which belonged to the file.
 ==========

38 passes?  Ridiculous (if it does that many on all types of drives). Totally unnecessary and way too slow.
Gutmann's method is also worthless in some cases:
Table 3
https://www.usenix.org/legacy/events/fast11/tech/full_papers/Wei.pdf
Gutmann himself disavowed the use of 35 passes:
"performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes."
He recommends shred for Linux, and the FOSS program Eraser for Windows
(https://eraser.heidi.ie)
https://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html#Epilogue
Next time do some research before making another of your clownish claims.