genrsa.pod revision 111147 
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<-des>]
13[B<-des3>]
14[B<-idea>]
15[B<-f4>]
16[B<-3>]
17[B<-rand file(s)>]
18[B<-engine id>]
19[B<numbits>]
20
21=head1 DESCRIPTION
22
23The B<genrsa> command generates an RSA private key.
24
25=head1 OPTIONS
26
27=over 4
28
29=item B<-out filename>
30
31the output filename. If this argument is not specified then standard output is
32used.  
33
34=item B<-passout arg>
35
36the output file password source. For more information about the format of B<arg>
37see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
38
39=item B<-des|-des3|-idea>
40
41These options encrypt the private key with the DES, triple DES, or the 
42IDEA ciphers respectively before outputting it. If none of these options is
43specified no encryption is used. If encryption is used a pass phrase is prompted
44for if it is not supplied via the B<-passout> argument.
45
46=item B<-F4|-3>
47
48the public exponent to use, either 65537 or 3. The default is 65537.
49
50=item B<-rand file(s)>
51
52a file or files containing random data used to seed the random number
53generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
54Multiple files can be specified separated by a OS-dependent character.
55The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
56all others.
57
58=item B<-engine id>
59
60specifying an engine (by it's unique B<id> string) will cause B<req>
61to attempt to obtain a functional reference to the specified engine,
62thus initialising it if needed. The engine will then be set as the default
63for all available algorithms.
64
65=item B<numbits>
66
67the size of the private key to generate in bits. This must be the last option
68specified. The default is 512.
69
70=back
71
72=head1 NOTES
73
74RSA private key generation essentially involves the generation of two prime
75numbers. When generating a private key various symbols will be output to
76indicate the progress of the generation. A B<.> represents each number which
77has passed an initial sieve test, B<+> means a number has passed a single
78round of the Miller-Rabin primality test. A newline means that the number has
79passed all the prime tests (the actual number depends on the key size).
80
81Because key generation is a random process the time taken to generate a key
82may vary somewhat.
83
84=head1 BUGS
85
86A quirk of the prime generation algorithm is that it cannot generate small
87primes. Therefore the number of bits should not be less that 64. For typical
88private keys this will not matter because for security reasons they will
89be much larger (typically 1024 bits).
90
91=head1 SEE ALSO
92
93L<gendsa(1)|gendsa(1)>
94
95=cut
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97