| =pod |
| |
| =head1 NAME |
| |
| openssl-genrsa, |
| genrsa - generate an RSA private key |
| |
| =head1 SYNOPSIS |
| |
| B<openssl> B<genrsa> |
| [B<-help>] |
| [B<-out filename>] |
| [B<-passout arg>] |
| [B<-aes128>] |
| [B<-aes192>] |
| [B<-aes256>] |
| [B<-aria128>] |
| [B<-aria192>] |
| [B<-aria256>] |
| [B<-camellia128>] |
| [B<-camellia192>] |
| [B<-camellia256>] |
| [B<-des>] |
| [B<-des3>] |
| [B<-idea>] |
| [B<-f4>] |
| [B<-3>] |
| [B<-rand file...>] |
| [B<-writerand file>] |
| [B<-engine id>] |
| [B<-primes num>] |
| [B<numbits>] |
| |
| =head1 DESCRIPTION |
| |
| The B<genrsa> command generates an RSA private key. |
| |
| =head1 OPTIONS |
| |
| =over 4 |
| |
| =item B<-help> |
| |
| Print out a usage message. |
| |
| =item B<-out filename> |
| |
| Output the key to the specified file. If this argument is not specified then |
| standard output is used. |
| |
| =item B<-passout arg> |
| |
| The output file password source. For more information about the format |
| of B<arg> see L<openssl(1)/Pass Phrase Options>. |
| |
| =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> |
| |
| 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 B<-passout> argument. |
| |
| =item B<-F4|-3> |
| |
| The public exponent to use, either 65537 or 3. The default is 65537. |
| |
| =item B<-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 B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for |
| all others. |
| |
| =item [B<-writerand file>] |
| |
| Writes random data to the specified I<file> upon exit. |
| This can be used with a subsequent B<-rand> flag. |
| |
| =item B<-engine id> |
| |
| Specifying an engine (by its unique B<id> string) will cause B<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. |
| |
| =item B<-primes num> |
| |
| Specify the number of primes to use while generating the RSA key. The B<num> |
| parameter must be a positive integer that is greater than 1 and less than 16. |
| If B<num> is greater than 2, then the generated key is called a 'multi-prime' |
| RSA key, which is defined in RFC 8017. |
| |
| =item B<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. |
| |
| =back |
| |
| =head1 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 B<.> represents each number which |
| has passed an initial sieve test, B<+> means a number has passed a single |
| round of the Miller-Rabin primality test, B<*> 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. |
| |
| =head1 SEE ALSO |
| |
| L<gendsa(1)> |
| |
| =head1 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 |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |