cac19d19e7
As per documentation, the RSA keys should not be smaller than 64bit (the documentation mentions something about a quirk in the prime generation algorithm). I am adding check into the code which used to be 16 for some reason. My primary motivation is to get rid of the last sentence in the documentation which suggest that typical keys have 1024 bits (instead updating it to the now default 2048). I *assume* that keys less than the 2048 bits (say 512) are used for education purposes. The 512 bits as the minimum have been suggested by Bernd Edlinger. Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Reviewed-by: Tim Hudson <tjh@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/4547)
128 lines
3.5 KiB
Text
128 lines
3.5 KiB
Text
=pod
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=head1 NAME
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openssl-genrsa,
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genrsa - generate an RSA private key
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=head1 SYNOPSIS
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B<openssl> B<genrsa>
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[B<-help>]
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[B<-out filename>]
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[B<-passout arg>]
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[B<-aes128>]
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[B<-aes192>]
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[B<-aes256>]
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[B<-aria128>]
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[B<-aria192>]
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[B<-aria256>]
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[B<-camellia128>]
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[B<-camellia192>]
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[B<-camellia256>]
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[B<-des>]
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[B<-des3>]
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[B<-idea>]
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[B<-f4>]
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[B<-3>]
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[B<-rand file...>]
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[B<-writerand file>]
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[B<-engine id>]
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[B<-primes num>]
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[B<numbits>]
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=head1 DESCRIPTION
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The B<genrsa> command generates an RSA private key.
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=head1 OPTIONS
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=over 4
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=item B<-help>
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Print out a usage message.
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=item B<-out filename>
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Output the key to the specified file. If this argument is not specified then
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standard output is used.
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=item B<-passout arg>
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The output file password source. For more information about the format
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of B<arg> see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
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=item B<-aes128|-aes192|-aes256|-aria128|-aria192|-aria256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea>
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These options encrypt the private key with specified
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cipher before outputting it. If none of these options is
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specified no encryption is used. If encryption is used a pass phrase is prompted
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for if it is not supplied via the B<-passout> argument.
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=item B<-F4|-3>
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The public exponent to use, either 65537 or 3. The default is 65537.
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=item B<-rand file...>
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A file or files containing random data used to seed the random number
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generator.
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Multiple files can be specified separated by an OS-dependent character.
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The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
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all others.
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=item [B<-writerand file>]
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Writes random data to the specified I<file> upon exit.
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This can be used with a subsequent B<-rand> flag.
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=item B<-engine id>
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Specifying an engine (by its unique B<id> string) will cause B<genrsa>
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to attempt to obtain a functional reference to the specified engine,
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thus initialising it if needed. The engine will then be set as the default
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for all available algorithms.
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=item B<-primes num>
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Specify the number of primes to use while generating the RSA key. The B<num>
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parameter must be a positive integer that is greater than 1 and less than 16.
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If B<num> is greater than 2, then the generated key is called a 'multi-prime'
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RSA key, which is defined in RFC 8017.
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=item B<numbits>
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The size of the private key to generate in bits. This must be the last option
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specified. The default is 2048 and values less than 512 are not allowed.
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=back
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=head1 NOTES
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RSA private key generation essentially involves the generation of two or more
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prime numbers. When generating a private key various symbols will be output to
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indicate the progress of the generation. A B<.> represents each number which
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has passed an initial sieve test, B<+> means a number has passed a single
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round of the Miller-Rabin primality test, B<*> means the current prime starts
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a regenerating progress due to some failed tests. A newline means that the number
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has passed all the prime tests (the actual number depends on the key size).
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Because key generation is a random process the time taken to generate a key
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may vary somewhat. But in general, more primes lead to less generation time
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of a key.
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=head1 SEE ALSO
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L<gendsa(1)>
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=head1 COPYRIGHT
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Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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