openssl-rand(1ssl) - phpMan

RAND(1SSL)                                   OpenSSL                                   RAND(1SSL)

NAME
       openssl-rand, rand - generate pseudo-random bytes

SYNOPSIS
       openssl rand [-help] [-out file] [-rand file...]  [-writerand file] [-base64] [-hex] num

DESCRIPTION
       This command generates num random bytes using a cryptographically secure pseudo random
       number generator (CSPRNG).

       The random bytes are generated using the RAND_bytes(3) function, which provides a security
       level of 256 bits, provided it managed to seed itself successfully from a trusted
       operating system entropy source.  Otherwise, the command will fail with a nonzero error
       code.  For more details, see RAND_bytes(3), RAND(7), and RAND_DRBG(7).

OPTIONS
       -help
           Print out a usage message.

       -out file
           Write to file instead of standard output.

       -rand file...
           A file or files containing random data used to seed the random number generator.
           Multiple files can be specified separated by an OS-dependent character.  The separator
           is ; for MS-Windows, , for OpenVMS, and : for all others.  Explicitly specifying a
           seed file is in general not necessary, see the "NOTES" section for more information.

       [-writerand file]
           Writes random data to the specified file upon exit.  This can be used with a
           subsequent -rand flag.

       -base64
           Perform base64 encoding on the output.

       -hex
           Show the output as a hex string.

NOTES
       Prior to OpenSSL 1.1.1, it was common for applications to store information about the
       state of the random-number generator in a file that was loaded at startup and rewritten
       upon exit. On modern operating systems, this is generally no longer necessary as OpenSSL
       will seed itself from a trusted entropy source provided by the operating system. The -rand
       and -writerand  flags are still supported for special platforms or circumstances that
       might require them.

       It is generally an error to use the same seed file more than once and every use of -rand
       should be paired with -writerand.

SEE ALSO
       RAND_bytes(3), RAND(7), RAND_DRBG(7)

COPYRIGHT
       Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use this file except in
       compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.

1.1.1f                                      2024-02-16                                 RAND(1SSL)

Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2024-04-23 08:30 @18.118.12.222 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)