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