5 genrsa - generate an RSA private key
30 The B<genrsa> command generates an RSA private key.
38 Print out a usage message.
40 =item B<-out filename>
42 Output the key to the specified file. If this argument is not specified then
43 standard output is used.
47 the output file password source. For more information about the format of B<arg>
48 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
50 =item B<-aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea>
52 These options encrypt the private key with specified
53 cipher before outputting it. If none of these options is
54 specified no encryption is used. If encryption is used a pass phrase is prompted
55 for if it is not supplied via the B<-passout> argument.
59 the public exponent to use, either 65537 or 3. The default is 65537.
61 =item B<-rand file(s)>
63 a file or files containing random data used to seed the random number
64 generator, or an EGD socket (see L<RAND_egd(3)>).
65 Multiple files can be specified separated by an OS-dependent character.
66 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
71 specifying an engine (by its unique B<id> string) will cause B<genrsa>
72 to attempt to obtain a functional reference to the specified engine,
73 thus initialising it if needed. The engine will then be set as the default
74 for all available algorithms.
78 the size of the private key to generate in bits. This must be the last option
79 specified. The default is 512.
85 RSA private key generation essentially involves the generation of two prime
86 numbers. When generating a private key various symbols will be output to
87 indicate the progress of the generation. A B<.> represents each number which
88 has passed an initial sieve test, B<+> means a number has passed a single
89 round of the Miller-Rabin primality test. A newline means that the number has
90 passed all the prime tests (the actual number depends on the key size).
92 Because key generation is a random process the time taken to generate a key
97 A quirk of the prime generation algorithm is that it cannot generate small
98 primes. Therefore the number of bits should not be less that 64. For typical
99 private keys this will not matter because for security reasons they will
100 be much larger (typically 1024 bits).
108 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
110 Licensed under the OpenSSL license (the "License"). You may not use
111 this file except in compliance with the License. You can obtain a copy
112 in the file LICENSE in the source distribution or at
113 L<https://www.openssl.org/source/license.html>.