rndbytes(1) - Linux man page

Name

rndbytes - Create random bytes

Synopsis

rndbytes [<options>]

Description

The program generates pseudo-random bytes and writes to standard output. The typical use of the program is redirect the output of this program to a ''dd'' command to overwrite a disk.

Options

-h Show a help text.
Long option: --help
-v Show the version number.
Long option: --version
-c Configure the program (set the options in the command line as permanent options).
Long option: --configure
-C Show the permanent options.
Long option: --show-configuration
-u Unconfigure, remove the permanent options set by the user.
Long option: --unconfigure
-r Reset the program, skip permanent options set by the user and defaults set by the administrator, use built-in defaults instead.
This option must appear before any of the following options.
Long option: --reset
-b blocksize: Specify the block size.
Long option: --blocksize=size
-n number: Specify the number of blocks (use 0 for an ''endless'' sequence until the program is aborted by a signal on Linux/Unix systems or by pressing a key on a Windows system).
Long option: --nblocks=number
-a prngs: Allow a set of PRNGs (pseudo random number generators). The arguments is either ''all'' or a comma-separated list of ''openssl'' (OpenSSL PRNG ), ''random'' (initstate()/setstate()/random() functions), ''rand48'' (nrand48() function), ''rand'' (rand() function).
Long option: --prngs=prngs

Return Value

The program returns exit status 0 on success, any other exit status indicates an error.

Examples

rndbytes -b 512 -n 0 -a openssl | dd of=/dev/sda

overwrites an entire hard disk using pseudo random data.

Caveats

Generating a large amount of pseudo random data is a slow process.

Unless you are in a military environment or top-secret banking environment it should be sufficient to run several passes of edbp to write fixed patterns to the disk.

For high security environments: If you want to make a hard disk unreadable visit your facility management unit and use a drilling machine and/or a hammer.

Author

Dirk Krause

History

Copyright And License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the following
  disclaimer in the documentation and/or other materials
  provided with the distribution.

* Neither the name of the Dirk Krause nor the names of
  contributors may be used to endorse or promote products
  derived from this software without specific prior written
  permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED . IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT , INDIRECT , INCIDENTAL , SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE , DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT ( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE , EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE .

Referenced By

rshdown(1)