mirror of
https://github.com/openssl/openssl.git
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97 lines
2.5 KiB
Plaintext
97 lines
2.5 KiB
Plaintext
=pod
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=head1 NAME
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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<-out filename>]
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[B<-passout arg>]
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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(s)>]
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[B<-engine id>]
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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<-out filename>
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the output filename. If this argument is not specified then standard output is
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used.
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=item B<-passout arg>
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the output file password source. For more information about the format of B<arg>
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see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
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=item B<-des|-des3|-idea>
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These options encrypt the private key with the DES, triple DES, or the
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IDEA ciphers respectively 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(s)>
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a file or files containing random data used to seed the random number
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generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
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Multiple files can be specified separated by a 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<-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<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 512.
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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 prime
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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. A newline means that the number has
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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.
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=head1 BUGS
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A quirk of the prime generation algorithm is that it cannot generate small
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primes. Therefore the number of bits should not be less that 64. For typical
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private keys this will not matter because for security reasons they will
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be much larger (typically 1024 bits).
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=head1 SEE ALSO
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L<gendsa(1)|gendsa(1)>
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=cut
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