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danilo
Asked: 2021-10-08 12:57:38 +0800 CST

What is the meaning of the three numbers 741 in "openssl rand -base64 741"?

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I'm creating an auth keyfile for mongodb and one way to do that is using: /usr/bin/openssl rand -base64 741 > $TMPFILE

I want to understand what is going on, I understood everything minus the meaning of three numbers 741

I couldn't find an explanation in the documentation.

openssl

1 Answers

  1. Best Answer

    It means it will use 741 bytes of random data and base64 it.

    Example with -hex 20 as this will be 40 long.

    $ /usr/bin/openssl rand -hex 20
51b40b347dfccefa9b4f8a13d36c4564760c2f82

    It is explained in the man page. See num at the end and the description:

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

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