openssl/doc/man1/openssl-rsautl.pod.in
Dr. David von Oheimb 0e89b39619 apps/x509 etc.: allow private key input when public key is expected
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/19076)
2023-03-14 17:26:49 +01:00

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=pod
{- OpenSSL::safe::output_do_not_edit_headers(); -}
=head1 NAME
openssl-rsautl - RSA command
=head1 SYNOPSIS
B<openssl> B<rsautl>
[B<-help>]
[B<-in> I<file>]
[B<-passin> I<arg>]
[B<-rev>]
[B<-out> I<file>]
[B<-inkey> I<filename>|I<uri>]
[B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>]
[B<-pubin>]
[B<-certin>]
[B<-sign>]
[B<-verify>]
[B<-encrypt>]
[B<-decrypt>]
[B<-pkcs>]
[B<-x931>]
[B<-oaep>]
[B<-raw>]
[B<-hexdump>]
[B<-asn1parse>]
{- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_r_synopsis -}
{- $OpenSSL::safe::opt_provider_synopsis -}
=head1 DESCRIPTION
This command has been deprecated.
The L<openssl-pkeyutl(1)> command should be used instead.
This command can be used to sign, verify, encrypt and decrypt
data using the RSA algorithm.
=head1 OPTIONS
=over 4
=item B<-help>
Print out a usage message.
=item B<-in> I<filename>
This specifies the input filename to read data from or standard input
if this option is not specified.
=item B<-passin> I<arg>
The passphrase used in the output file.
See see L<openssl-passphrase-options(1)>.
=item B<-rev>
Reverse the order of the input.
=item B<-out> I<filename>
Specifies the output filename to write to or standard output by
default.
=item B<-inkey> I<filename>|I<uri>
The input key, by default it should be an RSA private key.
=item B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>
The key format; unspecified by default.
See L<openssl-format-options(1)> for details.
=item B<-pubin>
By default a private key is read from the key input.
With this option a public key is read instead.
If the input contains no public key but a private key, its public part is used.
=item B<-certin>
The input is a certificate containing an RSA public key.
=item B<-sign>
Sign the input data and output the signed result. This requires
an RSA private key.
=item B<-verify>
Verify the input data and output the recovered data.
=item B<-encrypt>
Encrypt the input data using an RSA public key.
=item B<-decrypt>
Decrypt the input data using an RSA private key.
=item B<-pkcs>, B<-oaep>, B<-x931> B<-raw>
The padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP,
ANSI X9.31, or no padding, respectively.
For signatures, only B<-pkcs> and B<-raw> can be used.
Note: because of protection against Bleichenbacher attacks, decryption
using PKCS#1 v1.5 mode will not return errors in case padding check failed.
Use B<-raw> and inspect the returned value manually to check if the
padding is correct.
=item B<-hexdump>
Hex dump the output data.
=item B<-asn1parse>
Parse the ASN.1 output data, this is useful when combined with the
B<-verify> option.
{- $OpenSSL::safe::opt_engine_item -}
{- $OpenSSL::safe::opt_r_item -}
{- $OpenSSL::safe::opt_provider_item -}
=back
=head1 NOTES
Since this command uses the RSA algorithm directly, it can only be
used to sign or verify small pieces of data.
=head1 EXAMPLES
Examples equivalent to these can be found in the documentation for the
non-deprecated L<openssl-pkeyutl(1)> command.
Sign some data using a private key:
openssl rsautl -sign -in file -inkey key.pem -out sig
Recover the signed data
openssl rsautl -verify -in sig -inkey key.pem
Examine the raw signed data:
openssl rsautl -verify -in sig -inkey key.pem -raw -hexdump
0000 - 00 01 ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0010 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0020 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0030 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0040 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0050 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0060 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
0070 - ff ff ff ff 00 68 65 6c-6c 6f 20 77 6f 72 6c 64 .....hello world
The PKCS#1 block formatting is evident from this. If this was done using
encrypt and decrypt the block would have been of type 2 (the second byte)
and random padding data visible instead of the 0xff bytes.
It is possible to analyse the signature of certificates using this
command in conjunction with L<openssl-asn1parse(1)>. Consider the self signed
example in F<certs/pca-cert.pem>. Running L<openssl-asn1parse(1)> as follows
yields:
openssl asn1parse -in pca-cert.pem
0:d=0 hl=4 l= 742 cons: SEQUENCE
4:d=1 hl=4 l= 591 cons: SEQUENCE
8:d=2 hl=2 l= 3 cons: cont [ 0 ]
10:d=3 hl=2 l= 1 prim: INTEGER :02
13:d=2 hl=2 l= 1 prim: INTEGER :00
16:d=2 hl=2 l= 13 cons: SEQUENCE
18:d=3 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
29:d=3 hl=2 l= 0 prim: NULL
31:d=2 hl=2 l= 92 cons: SEQUENCE
33:d=3 hl=2 l= 11 cons: SET
35:d=4 hl=2 l= 9 cons: SEQUENCE
37:d=5 hl=2 l= 3 prim: OBJECT :countryName
42:d=5 hl=2 l= 2 prim: PRINTABLESTRING :AU
....
599:d=1 hl=2 l= 13 cons: SEQUENCE
601:d=2 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
612:d=2 hl=2 l= 0 prim: NULL
614:d=1 hl=3 l= 129 prim: BIT STRING
The final BIT STRING contains the actual signature. It can be extracted with:
openssl asn1parse -in pca-cert.pem -out sig -noout -strparse 614
The certificate public key can be extracted with:
openssl x509 -in test/testx509.pem -pubkey -noout >pubkey.pem
The signature can be analysed with:
openssl rsautl -in sig -verify -asn1parse -inkey pubkey.pem -pubin
0:d=0 hl=2 l= 32 cons: SEQUENCE
2:d=1 hl=2 l= 12 cons: SEQUENCE
4:d=2 hl=2 l= 8 prim: OBJECT :md5
14:d=2 hl=2 l= 0 prim: NULL
16:d=1 hl=2 l= 16 prim: OCTET STRING
0000 - f3 46 9e aa 1a 4a 73 c9-37 ea 93 00 48 25 08 b5 .F...Js.7...H%..
This is the parsed version of an ASN1 DigestInfo structure. It can be seen that
the digest used was md5. The actual part of the certificate that was signed can
be extracted with:
openssl asn1parse -in pca-cert.pem -out tbs -noout -strparse 4
and its digest computed with:
openssl md5 -c tbs
MD5(tbs)= f3:46:9e:aa:1a:4a:73:c9:37:ea:93:00:48:25:08:b5
which it can be seen agrees with the recovered value above.
=head1 SEE ALSO
L<openssl(1)>,
L<openssl-pkeyutl(1)>,
L<openssl-dgst(1)>,
L<openssl-rsa(1)>,
L<openssl-genrsa(1)>
=head1 HISTORY
This command was deprecated in OpenSSL 3.0.
The B<-engine> option was deprecated in OpenSSL 3.0.
=head1 COPYRIGHT
Copyright 2000-2021 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