1=pod
2{- OpenSSL::safe::output_do_not_edit_headers(); -}
3
4=head1 NAME
5
6openssl-genrsa - generate an RSA private key
7
8=head1 SYNOPSIS
9
10B<openssl> B<genrsa>
11[B<-help>]
12[B<-out> I<filename>]
13[B<-passout> I<arg>]
14[B<-aes128>]
15[B<-aes192>]
16[B<-aes256>]
17[B<-aria128>]
18[B<-aria192>]
19[B<-aria256>]
20[B<-camellia128>]
21[B<-camellia192>]
22[B<-camellia256>]
23[B<-des>]
24[B<-des3>]
25[B<-idea>]
26[B<-F4>]
27[B<-f4>]
28[B<-3>]
29[B<-primes> I<num>]
30[B<-verbose>]
31[B<-traditional>]
32{- $OpenSSL::safe::opt_r_synopsis -}
33{- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_provider_synopsis -}
34[B<numbits>]
35
36=head1 DESCRIPTION
37
38This command generates an RSA private key.
39
40=head1 OPTIONS
41
42=over 4
43
44=item B<-help>
45
46Print out a usage message.
47
48=item B<-out> I<filename>
49
50Output the key to the specified file. If this argument is not specified then
51standard output is used.
52
53=item B<-passout> I<arg>
54
55The output file password source. For more information about the format
56see L<openssl-passphrase-options(1)>.
57
58=item B<-aes128>, B<-aes192>, B<-aes256>, B<-aria128>, B<-aria192>, B<-aria256>, B<-camellia128>, B<-camellia192>, B<-camellia256>, B<-des>, B<-des3>, B<-idea>
59
60These options encrypt the private key with specified
61cipher before outputting it. If none of these options is
62specified no encryption is used. If encryption is used a pass phrase is prompted
63for if it is not supplied via the B<-passout> argument.
64
65=item B<-F4>, B<-f4>, B<-3>
66
67The public exponent to use, either 65537 or 3. The default is 65537.
68The B<-3> option has been deprecated.
69
70=item B<-primes> I<num>
71
72Specify the number of primes to use while generating the RSA key. The I<num>
73parameter must be a positive integer that is greater than 1 and less than 16.
74If I<num> is greater than 2, then the generated key is called a 'multi-prime'
75RSA key, which is defined in RFC 8017.
76
77=item B<-verbose>
78
79Print extra details about the operations being performed.
80
81=item B<-traditional>
82
83Write the key using the traditional PKCS#1 format instead of the PKCS#8 format.
84
85{- $OpenSSL::safe::opt_r_item -}
86
87{- $OpenSSL::safe::opt_engine_item -}
88
89{- $OpenSSL::safe::opt_provider_item -}
90
91=item B<numbits>
92
93The size of the private key to generate in bits. This must be the last option
94specified. The default is 2048 and values less than 512 are not allowed.
95
96=back
97
98=head1 NOTES
99
100RSA private key generation essentially involves the generation of two or more
101prime numbers. When generating a private key various symbols will be output to
102indicate the progress of the generation. A B<.> represents each number which
103has passed an initial sieve test, B<+> means a number has passed a single
104round of the Miller-Rabin primality test, B<*> means the current prime starts
105a regenerating progress due to some failed tests. A newline means that the number
106has passed all the prime tests (the actual number depends on the key size).
107
108Because key generation is a random process the time taken to generate a key
109may vary somewhat. But in general, more primes lead to less generation time
110of a key.
111
112=head1 SEE ALSO
113
114L<openssl(1)>,
115L<openssl-genpkey(1)>,
116L<openssl-gendsa(1)>
117
118=head1 COPYRIGHT
119
120Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
121
122Licensed under the Apache License 2.0 (the "License").  You may not use
123this file except in compliance with the License.  You can obtain a copy
124in the file LICENSE in the source distribution or at
125L<https://www.openssl.org/source/license.html>.
126
127=cut
128