genrsa.pod revision 291721 
1=pod
2
3=head1 NAME
4
5genrsa - generate an RSA private key
6
7=head1 SYNOPSIS
8
9B<openssl> B<genrsa>
10[B<-out filename>]
11[B<-passout arg>]
12[B<-aes128>]
13[B<-aes192>]
14[B<-aes256>]
15[B<-camellia128>]
16[B<-camellia192>]
17[B<-camellia256>]
18[B<-des>]
19[B<-des3>]
20[B<-idea>]
21[B<-f4>]
22[B<-3>]
23[B<-rand file(s)>]
24[B<-engine id>]
25[B<numbits>]
26
27=head1 DESCRIPTION
28
29The B<genrsa> command generates an RSA private key.
30
31=head1 OPTIONS
32
33=over 4
34
35=item B<-out filename>
36
37the output filename. If this argument is not specified then standard output is
38used.  
39
40=item B<-passout arg>
41
42the output file password source. For more information about the format of B<arg>
43see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
44
45=item B<-aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea>
46
47These options encrypt the private key with specified
48cipher before outputting it. If none of these options is
49specified no encryption is used. If encryption is used a pass phrase is prompted
50for if it is not supplied via the B<-passout> argument.
51
52=item B<-F4|-3>
53
54the public exponent to use, either 65537 or 3. The default is 65537.
55
56=item B<-rand file(s)>
57
58a file or files containing random data used to seed the random number
59generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
60Multiple files can be specified separated by a OS-dependent character.
61The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
62all others.
63
64=item B<-engine id>
65
66specifying an engine (by its unique B<id> string) will cause B<genrsa>
67to attempt to obtain a functional reference to the specified engine,
68thus initialising it if needed. The engine will then be set as the default
69for all available algorithms.
70
71=item B<numbits>
72
73the size of the private key to generate in bits. This must be the last option
74specified. The default is 512.
75
76=back
77
78=head1 NOTES
79
80RSA private key generation essentially involves the generation of two prime
81numbers. When generating a private key various symbols will be output to
82indicate the progress of the generation. A B<.> represents each number which
83has passed an initial sieve test, B<+> means a number has passed a single
84round of the Miller-Rabin primality test. A newline means that the number has
85passed all the prime tests (the actual number depends on the key size).
86
87Because key generation is a random process the time taken to generate a key
88may vary somewhat.
89
90=head1 BUGS
91
92A quirk of the prime generation algorithm is that it cannot generate small
93primes. Therefore the number of bits should not be less that 64. For typical
94private keys this will not matter because for security reasons they will
95be much larger (typically 1024 bits).
96
97=head1 SEE ALSO
98
99L<gendsa(1)|gendsa(1)>
100
101=cut
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