genrsa.pod 3.5 KB

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  1. =pod
  2. =head1 NAME
  3. openssl-genrsa,
  4. genrsa - generate an RSA private key
  5. =head1 SYNOPSIS
  6. B<openssl> B<genrsa>
  7. [B<-help>]
  8. [B<-out filename>]
  9. [B<-passout arg>]
  10. [B<-aes128>]
  11. [B<-aes192>]
  12. [B<-aes256>]
  13. [B<-aria128>]
  14. [B<-aria192>]
  15. [B<-aria256>]
  16. [B<-camellia128>]
  17. [B<-camellia192>]
  18. [B<-camellia256>]
  19. [B<-des>]
  20. [B<-des3>]
  21. [B<-idea>]
  22. [B<-f4>]
  23. [B<-3>]
  24. [B<-rand file...>]
  25. [B<-writerand file>]
  26. [B<-engine id>]
  27. [B<-primes num>]
  28. [B<numbits>]
  29. =head1 DESCRIPTION
  30. The B<genrsa> command generates an RSA private key.
  31. =head1 OPTIONS
  32. =over 4
  33. =item B<-help>
  34. Print out a usage message.
  35. =item B<-out filename>
  36. Output the key to the specified file. If this argument is not specified then
  37. standard output is used.
  38. =item B<-passout arg>
  39. The output file password source. For more information about the format
  40. of B<arg> see L<openssl(1)/Pass Phrase Options>.
  41. =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>
  42. These options encrypt the private key with specified
  43. cipher before outputting it. If none of these options is
  44. specified no encryption is used. If encryption is used a pass phrase is prompted
  45. for if it is not supplied via the B<-passout> argument.
  46. =item B<-F4|-3>
  47. The public exponent to use, either 65537 or 3. The default is 65537.
  48. =item B<-rand file...>
  49. A file or files containing random data used to seed the random number
  50. generator.
  51. Multiple files can be specified separated by an OS-dependent character.
  52. The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
  53. all others.
  54. =item [B<-writerand file>]
  55. Writes random data to the specified I<file> upon exit.
  56. This can be used with a subsequent B<-rand> flag.
  57. =item B<-engine id>
  58. Specifying an engine (by its unique B<id> string) will cause B<genrsa>
  59. to attempt to obtain a functional reference to the specified engine,
  60. thus initialising it if needed. The engine will then be set as the default
  61. for all available algorithms.
  62. =item B<-primes num>
  63. Specify the number of primes to use while generating the RSA key. The B<num>
  64. parameter must be a positive integer that is greater than 1 and less than 16.
  65. If B<num> is greater than 2, then the generated key is called a 'multi-prime'
  66. RSA key, which is defined in RFC 8017.
  67. =item B<numbits>
  68. The size of the private key to generate in bits. This must be the last option
  69. specified. The default is 2048 and values less than 512 are not allowed.
  70. =back
  71. =head1 NOTES
  72. RSA private key generation essentially involves the generation of two or more
  73. prime numbers. When generating a private key various symbols will be output to
  74. indicate the progress of the generation. A B<.> represents each number which
  75. has passed an initial sieve test, B<+> means a number has passed a single
  76. round of the Miller-Rabin primality test, B<*> means the current prime starts
  77. a regenerating progress due to some failed tests. A newline means that the number
  78. has passed all the prime tests (the actual number depends on the key size).
  79. Because key generation is a random process the time taken to generate a key
  80. may vary somewhat. But in general, more primes lead to less generation time
  81. of a key.
  82. =head1 SEE ALSO
  83. L<gendsa(1)>
  84. =head1 COPYRIGHT
  85. Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
  86. Licensed under the OpenSSL license (the "License"). You may not use
  87. this file except in compliance with the License. You can obtain a copy
  88. in the file LICENSE in the source distribution or at
  89. L<https://www.openssl.org/source/license.html>.
  90. =cut