xref: /openssl/doc/man1/openssl-rsautl.pod.in (revision da1c088f) 
1=pod
2{- OpenSSL::safe::output_do_not_edit_headers(); -}
3
4=head1 NAME
5
6openssl-rsautl - RSA command
7
8=head1 SYNOPSIS
9
10B<openssl> B<rsautl>
11[B<-help>]
12[B<-in> I<file>]
13[B<-passin> I<arg>]
14[B<-rev>]
15[B<-out> I<file>]
16[B<-inkey> I<filename>|I<uri>]
17[B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>]
18[B<-pubin>]
19[B<-certin>]
20[B<-sign>]
21[B<-verify>]
22[B<-encrypt>]
23[B<-decrypt>]
24[B<-pkcs>]
25[B<-x931>]
26[B<-oaep>]
27[B<-raw>]
28[B<-hexdump>]
29[B<-asn1parse>]
30{- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_r_synopsis -}
31{- $OpenSSL::safe::opt_provider_synopsis -}
32
33=head1 DESCRIPTION
34
35This command has been deprecated.
36The L<openssl-pkeyutl(1)> command should be used instead.
37
38This command can be used to sign, verify, encrypt and decrypt
39data using the RSA algorithm.
40
41=head1 OPTIONS
42
43=over 4
44
45=item B<-help>
46
47Print out a usage message.
48
49=item B<-in> I<filename>
50
51This specifies the input filename to read data from or standard input
52if this option is not specified.
53
54=item B<-passin> I<arg>
55
56The passphrase used in the output file.
57See see L<openssl-passphrase-options(1)>.
58
59=item B<-rev>
60
61Reverse the order of the input.
62
63=item B<-out> I<filename>
64
65Specifies the output filename to write to or standard output by
66default.
67
68=item B<-inkey> I<filename>|I<uri>
69
70The input key, by default it should be an RSA private key.
71
72=item B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>
73
74The key format; unspecified by default.
75See L<openssl-format-options(1)> for details.
76
77=item B<-pubin>
78
79By default a private key is read from the key input.
80With this option a public key is read instead.
81If the input contains no public key but a private key, its public part is used.
82
83=item B<-certin>
84
85The input is a certificate containing an RSA public key.
86
87=item B<-sign>
88
89Sign the input data and output the signed result. This requires
90an RSA private key.
91
92=item B<-verify>
93
94Verify the input data and output the recovered data.
95
96=item B<-encrypt>
97
98Encrypt the input data using an RSA public key.
99
100=item B<-decrypt>
101
102Decrypt the input data using an RSA private key.
103
104=item B<-pkcs>, B<-oaep>, B<-x931>, B<-raw>
105
106The padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP,
107ANSI X9.31, or no padding, respectively.
108For signatures, only B<-pkcs> and B<-raw> can be used.
109
110Note: because of protection against Bleichenbacher attacks, decryption
111using PKCS#1 v1.5 mode will not return errors in case padding check failed.
112Use B<-raw> and inspect the returned value manually to check if the
113padding is correct.
114
115=item B<-hexdump>
116
117Hex dump the output data.
118
119=item B<-asn1parse>
120
121Parse the ASN.1 output data, this is useful when combined with the
122B<-verify> option.
123
124{- $OpenSSL::safe::opt_engine_item -}
125
126{- $OpenSSL::safe::opt_r_item -}
127
128{- $OpenSSL::safe::opt_provider_item -}
129
130=back
131
132=head1 NOTES
133
134Since this command uses the RSA algorithm directly, it can only be
135used to sign or verify small pieces of data.
136
137=head1 EXAMPLES
138
139Examples equivalent to these can be found in the documentation for the
140non-deprecated L<openssl-pkeyutl(1)> command.
141
142Sign some data using a private key:
143
144 openssl rsautl -sign -in file -inkey key.pem -out sig
145
146Recover the signed data
147
148 openssl rsautl -verify -in sig -inkey key.pem
149
150Examine the raw signed data:
151
152 openssl rsautl -verify -in sig -inkey key.pem -raw -hexdump
153
154 0000 - 00 01 ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
155 0010 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
156 0020 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
157 0030 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
158 0040 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
159 0050 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
160 0060 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff   ................
161 0070 - ff ff ff ff 00 68 65 6c-6c 6f 20 77 6f 72 6c 64   .....hello world
162
163The PKCS#1 block formatting is evident from this. If this was done using
164encrypt and decrypt the block would have been of type 2 (the second byte)
165and random padding data visible instead of the 0xff bytes.
166
167It is possible to analyse the signature of certificates using this
168command in conjunction with L<openssl-asn1parse(1)>. Consider the self signed
169example in F<certs/pca-cert.pem>. Running L<openssl-asn1parse(1)> as follows
170yields:
171
172 openssl asn1parse -in pca-cert.pem
173
174    0:d=0  hl=4 l= 742 cons: SEQUENCE
175    4:d=1  hl=4 l= 591 cons:  SEQUENCE
176    8:d=2  hl=2 l=   3 cons:   cont [ 0 ]
177   10:d=3  hl=2 l=   1 prim:    INTEGER           :02
178   13:d=2  hl=2 l=   1 prim:   INTEGER           :00
179   16:d=2  hl=2 l=  13 cons:   SEQUENCE
180   18:d=3  hl=2 l=   9 prim:    OBJECT            :md5WithRSAEncryption
181   29:d=3  hl=2 l=   0 prim:    NULL
182   31:d=2  hl=2 l=  92 cons:   SEQUENCE
183   33:d=3  hl=2 l=  11 cons:    SET
184   35:d=4  hl=2 l=   9 cons:     SEQUENCE
185   37:d=5  hl=2 l=   3 prim:      OBJECT            :countryName
186   42:d=5  hl=2 l=   2 prim:      PRINTABLESTRING   :AU
187  ....
188  599:d=1  hl=2 l=  13 cons:  SEQUENCE
189  601:d=2  hl=2 l=   9 prim:   OBJECT            :md5WithRSAEncryption
190  612:d=2  hl=2 l=   0 prim:   NULL
191  614:d=1  hl=3 l= 129 prim:  BIT STRING
192
193
194The final BIT STRING contains the actual signature. It can be extracted with:
195
196 openssl asn1parse -in pca-cert.pem -out sig -noout -strparse 614
197
198The certificate public key can be extracted with:
199
200 openssl x509 -in test/testx509.pem -pubkey -noout >pubkey.pem
201
202The signature can be analysed with:
203
204 openssl rsautl -in sig -verify -asn1parse -inkey pubkey.pem -pubin
205
206    0:d=0  hl=2 l=  32 cons: SEQUENCE
207    2:d=1  hl=2 l=  12 cons:  SEQUENCE
208    4:d=2  hl=2 l=   8 prim:   OBJECT            :md5
209   14:d=2  hl=2 l=   0 prim:   NULL
210   16:d=1  hl=2 l=  16 prim:  OCTET STRING
211      0000 - f3 46 9e aa 1a 4a 73 c9-37 ea 93 00 48 25 08 b5   .F...Js.7...H%..
212
213This is the parsed version of an ASN1 DigestInfo structure. It can be seen that
214the digest used was md5. The actual part of the certificate that was signed can
215be extracted with:
216
217 openssl asn1parse -in pca-cert.pem -out tbs -noout -strparse 4
218
219and its digest computed with:
220
221 openssl md5 -c tbs
222 MD5(tbs)= f3:46:9e:aa:1a:4a:73:c9:37:ea:93:00:48:25:08:b5
223
224which it can be seen agrees with the recovered value above.
225
226=head1 SEE ALSO
227
228L<openssl(1)>,
229L<openssl-pkeyutl(1)>,
230L<openssl-dgst(1)>,
231L<openssl-rsa(1)>,
232L<openssl-genrsa(1)>
233
234=head1 HISTORY
235
236This command was deprecated in OpenSSL 3.0.
237
238The B<-engine> option was deprecated in OpenSSL 3.0.
239
240=head1 COPYRIGHT
241
242Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
243
244Licensed under the Apache License 2.0 (the "License").  You may not use
245this file except in compliance with the License.  You can obtain a copy
246in the file LICENSE in the source distribution or at
247L<https://www.openssl.org/source/license.html>.
248
249=cut
250