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GENRSA(1)			    OpenSSL			     GENRSA(1)

NAME
       openssl-genrsa, genrsa -	generate an RSA	private	key

SYNOPSIS
       openssl genrsa [-help] [-out filename] [-passout	arg] [-aes128]
       [-aes192] [-aes256] [-aria128] [-aria192] [-aria256] [-camellia128]
       [-camellia192] [-camellia256] [-des] [-des3] [-idea] [-f4] [-3] [-rand
       file...]	 [-writerand file] [-engine id]	[-primes num] [numbits]

DESCRIPTION
       The genrsa command generates an RSA private key.

OPTIONS
       -help
	   Print out a usage message.

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

       -passout	arg
	   The output file password source. For	 more  information  about  the
	   format of arg see "Pass Phrase Options" in openssl(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|-3
	   The public exponent to use, either  65537  or  3.  The  default  is
	   65537.

       -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.

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

       -engine id
	   Specifying an engine	(by its	unique id string) will cause genrsa to
	   attempt  to	obtain a functional reference to the specified engine,
	   thus	initialising it	if needed. The engine will then	be set as  the
	   default for all available algorithms.

       -primes num
	   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.

       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.

NOTES
       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.

SEE ALSO
       gendsa(1)

COPYRIGHT
       Copyright 2000-2021 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>.

1.1.1w				  2023-09-11			     GENRSA(1)

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