doc/man1/openssl-genrsa.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 openssl-genrsa - generate an RSA private key
   6
   7 =head1 SYNOPSIS
   8
   9 B<openssl> B<genrsa>
  10 [B<-help>]
  11 [B<-out> I<filename>]
  12 [B<-passout> I<arg>]
  13 [B<-aes128>]
  14 [B<-aes192>]
  15 [B<-aes256>]
  16 [B<-aria128>]
  17 [B<-aria192>]
  18 [B<-aria256>]
  19 [B<-camellia128>]
  20 [B<-camellia192>]
  21 [B<-camellia256>]
  22 [B<-des>]
  23 [B<-des3>]
  24 [B<-idea>]
  25 [B<-f4>|B<-3>]
  26 [B<-rand> I<files>]
  27 [B<-writerand> I<file>]
  28 [B<-engine> I<id>]
  29 [B<-primes> I<num>]
  30 [B<-verbose>]
  31 [B<numbits>]
  32
  33 =for openssl ifdef engine
  34
  35 =head1 DESCRIPTION
  36
  37 This command generates an RSA private key.
  38
  39 =head1 OPTIONS
  40
  41 =over 4
  42
  43 =item B<-help>
  44
  45 Print out a usage message.
  46
  47 =item B<-out> I<filename>
  48
  49 Output the key to the specified file. If this argument is not specified then
  50 standard output is used.
  51
  52 =item B<-passout> I<arg>
  53
  54 The output file password source. For more information about the format
  55 see L<openssl(1)/Pass Phrase Options>.
  56
  57 =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>
  58
  59 These options encrypt the private key with specified
  60 cipher before outputting it. If none of these options is
  61 specified no encryption is used. If encryption is used a pass phrase is prompted
  62 for if it is not supplied via the B<-passout> argument.
  63
  64 =item B<-F4>|B<-3>
  65
  66 The public exponent to use, either 65537 or 3. The default is 65537.
  67
  68 =item B<-rand> I<files>, B<-writerand> I<file>
  69
  70 See L<openssl(1)/Random State Options> for more information.
  71
  72 =item B<-engine> I<id>
  73
  74 Specifying an engine (by its unique I<id> string) will cause this command
  75 to attempt to obtain a functional reference to the specified engine,
  76 thus initialising it if needed. The engine will then be set as the default
  77 for all available algorithms.
  78
  79 =item B<-primes> I<num>
  80
  81 Specify the number of primes to use while generating the RSA key. The I<num>
  82 parameter must be a positive integer that is greater than 1 and less than 16.
  83 If I<num> is greater than 2, then the generated key is called a 'multi-prime'
  84 RSA key, which is defined in RFC 8017.
  85
  86 =item B<-verbose>
  87
  88 Print extra details about the operations being performed.
  89
  90 =item B<numbits>
  91
  92 The size of the private key to generate in bits. This must be the last option
  93 specified. The default is 2048 and values less than 512 are not allowed.
  94
  95 =back
  96
  97 =head1 NOTES
  98
  99 RSA private key generation essentially involves the generation of two or more
 100 prime numbers. When generating a private key various symbols will be output to
 101 indicate the progress of the generation. A B<.> represents each number which
 102 has passed an initial sieve test, B<+> means a number has passed a single
 103 round of the Miller-Rabin primality test, B<*> means the current prime starts
 104 a regenerating progress due to some failed tests. A newline means that the number
 105 has passed all the prime tests (the actual number depends on the key size).
 106
 107 Because key generation is a random process the time taken to generate a key
 108 may vary somewhat. But in general, more primes lead to less generation time
 109 of a key.
 110
 111 =head1 SEE ALSO
 112
 113 L<openssl(1)>,
 114 L<openssl-gendsa(1)>
 115
 116 =head1 COPYRIGHT
 117
 118 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
 119
 120 Licensed under the Apache License 2.0 (the "License").  You may not use
 121 this file except in compliance with the License.  You can obtain a copy
 122 in the file LICENSE in the source distribution or at
 123 L<https://www.openssl.org/source/license.html>.
 124
 125 =cut