openssl/doc/man1/openssl-rsa.pod

=pod

=head1 NAME

openssl-rsa - RSA key processing tool

=head1 SYNOPSIS

B<openssl> B<rsa>
[B<-help>]
[B<-inform> B<DER>|B<PEM>]
[B<-outform> B<DER>|B<PEM>]
[B<-in> I<filename>]
[B<-passin> I<arg>]
[B<-out> I<filename>]
[B<-passout> I<arg>]
[B<-aes128>]
[B<-aes192>]
[B<-aes256>]
[B<-aria128>]
[B<-aria192>]
[B<-aria256>]
[B<-camellia128>]
[B<-camellia192>]
[B<-camellia256>]
[B<-des>]
[B<-des3>]
[B<-idea>]
[B<-text>]
[B<-noout>]
[B<-modulus>]
[B<-check>]
[B<-pubin>]
[B<-pubout>]
[B<-RSAPublicKey_in>]
[B<-RSAPublicKey_out>]
[B<-engine> I<id>]

=for openssl ifdef pvk-strong pvk-weak pvk-none engine

=head1 DESCRIPTION

This command processes RSA keys. They can be converted between
various forms and their components printed out. B<Note> this command uses the
traditional SSLeay compatible format for private key encryption: newer
applications should use the more secure PKCS#8 format using the
L<openssl-pkcs8(1)> command.

=head1 OPTIONS

=over 4

=item B<-help>

Print out a usage message.

=item B<-inform> B<DER>|B<PEM>

This specifies the input format. The B<DER> option uses an ASN1 DER encoded
form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format.
The B<PEM> form is the default format: it consists of the B<DER> format base64
encoded with additional header and footer lines. On input PKCS#8 format private
keys are also accepted.

=item B<-outform> B<DER>|B<PEM>

This specifies the output format, the options have the same meaning and default
as the B<-inform> option.

=item B<-in> I<filename>

This specifies the input filename to read a key from or standard input if this
option is not specified. If the key is encrypted a pass phrase will be
prompted for.

=item B<-passin> I<arg>, B<-passout> I<arg>

The password source for the input and output file.
For more information about the format of B<arg>
see L<openssl(1)/Pass Phrase Options>.

=item B<-out> I<filename>

This specifies the output filename to write a key to or standard output if this
option is not specified. If any encryption options are set then a pass phrase
will be prompted for. The output filename should B<not> be the same as the input
filename.

=item B<-aes128>, B<-aes192>, B<-aes256>, B<-aria128>, B<-aria192>, B<-aria256>, B<-camellia128>, B<-camellia192>, B<-camellia256>, B<-des>, B<-des3>, B<-idea>

These options encrypt the private key with the specified
cipher before outputting it. A pass phrase is prompted for.
If none of these options is specified the key is written in plain text. This
means that this command can be used to remove the pass phrase from a key
by not giving any encryption option is given, or to add or change the pass
phrase by setting them.
These options can only be used with PEM format output files.

=item B<-text>

Prints out the various public or private key components in
plain text in addition to the encoded version.

=item B<-noout>

This option prevents output of the encoded version of the key.

=item B<-modulus>

This option prints out the value of the modulus of the key.

=item B<-check>

This option checks the consistency of an RSA private key.

=item B<-pubin>

By default a private key is read from the input file: with this
option a public key is read instead.

=item B<-pubout>

By default a private key is output: with this option a public
key will be output instead. This option is automatically set if
the input is a public key.

=item B<-RSAPublicKey_in>, B<-RSAPublicKey_out>

Like B<-pubin> and B<-pubout> except B<RSAPublicKey> format is used instead.

=item B<-engine> I<id>

Specifying an engine (by its unique I<id> string) will cause this command
to attempt to obtain a functional reference to the specified engine,
thus initialising it if needed. The engine will then be set as the default
for all available algorithms.

=back

=head1 NOTES

The PEM private key format uses the header and footer lines:

 -----BEGIN RSA PRIVATE KEY-----
 -----END RSA PRIVATE KEY-----

The PEM public key format uses the header and footer lines:

 -----BEGIN PUBLIC KEY-----
 -----END PUBLIC KEY-----

The PEM B<RSAPublicKey> format uses the header and footer lines:

 -----BEGIN RSA PUBLIC KEY-----
 -----END RSA PUBLIC KEY-----

=head1 EXAMPLES

To remove the pass phrase on an RSA private key:

 openssl rsa -in key.pem -out keyout.pem

To encrypt a private key using triple DES:

 openssl rsa -in key.pem -des3 -out keyout.pem

To convert a private key from PEM to DER format:

 openssl rsa -in key.pem -outform DER -out keyout.der

To print out the components of a private key to standard output:

 openssl rsa -in key.pem -text -noout

To just output the public part of a private key:

 openssl rsa -in key.pem -pubout -out pubkey.pem

Output the public part of a private key in B<RSAPublicKey> format:

 openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem

=head1 BUGS

There should be an option that automatically handles F<.key> files,
without having to manually edit them.

=head1 SEE ALSO

L<openssl(1)>,
L<openssl-pkcs8(1)>,
L<openssl-dsa(1)>,
L<openssl-genrsa(1)>,
L<openssl-gendsa(1)>

=head1 COPYRIGHT

Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut