openssl-genrsa - generate an RSA private key

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       Licensed under the Apache License 2.0 (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>.

3.4.1                                              2025-04-03                               OPENSSL-GENRSA(1SSL)

       This command generates an RSA private key.

       openssl-genrsa - generate an RSA private key

       RSA  private  key  generation  essentially  involves  the  generation  of two or more prime numbers. When
       generating a private key various symbols will be output to indicate the progress of the generation.  A  .
       represents each number which has passed an initial sieve test, + means a number has passed a single round
       of  the Miller-Rabin primality test, * means the current prime starts a regenerating progress due to some
       failed tests. A newline means that the number has passed all the prime tests (the actual  number  depends
       on the key size).

       Because  key  generation  is  a random process the time taken to generate a key may vary somewhat. But in
       general, more primes lead to less generation time of a key.

-help
           Print out a usage message.

       -outfilename
           Output the key to the specified file. If this argument is not specified then standard output is used.

       -passoutarg
           The    output    file    password    source.    For   more   information   about   the   format   see
           openssl-passphrase-options(1).

       -aes128, -aes192, -aes256, -aria128, -aria192, -aria256, -camellia128, -camellia192, -camellia256, -des,
       -des3, -idea
           These options encrypt the private key with specified cipher before outputting it. If  none  of  these
           options is specified no encryption is used. If encryption is used a pass phrase is prompted for if it
           is not supplied via the -passout argument.

       -F4, -f4, -3
           The  public  exponent  to  use,  either  65537  or  3.  The default is 65537.  The -3 option has been
           deprecated.

       -primesnum
           Specify the number of primes to use while generating the  RSA  key.  The  num  parameter  must  be  a
           positive  integer  that  is  greater  than  1  and  less than 16.  If num is greater than 2, then the
           generated key is called a 'multi-prime' RSA key, which is defined in RFC 8017.

       -verbose
           Print extra details about the operations being performed.

       -quiet
           Print fewer details about the operations being performed, which may be handy during batch scripts and
           pipelines.

       -traditional
           Write the key using the traditional PKCS#1 format instead of the PKCS#8 format.

       -randfiles, -writerandfile
           See "Random State Options" in openssl(1) for details.

       -engineid
           See "Engine Options" in openssl(1).  This option is deprecated.

       -providername-provider-pathpath-propquerypropq
           See "Provider Options" in openssl(1), provider(7), and property(7).

       numbits
           The size of the private key to generate in bits. This must be the last option specified. The  default
           is 2048 and values less than 512 are not allowed.

openssl(1), openssl-genpkey(1), openssl-gendsa(1)

opensslgenrsa [-help] [-outfilename] [-passoutarg] [-aes128] [-aes192] [-aes256] [-aria128] [-aria192]
       [-aria256] [-camellia128] [-camellia192] [-camellia256] [-des] [-des3] [-idea] [-F4] [-f4] [-3] [-primesnum] [-verbose] [-quiet] [-traditional] [-randfiles] [-writerandfile] [-engineid] [-providername]
       [-provider-pathpath] [-propquerypropq] [numbits]