14 [B<-keyform PEM|DER|ENGINE>]
29 The B<rsautl> command can be used to sign, verify, encrypt and decrypt
30 data using the RSA algorithm.
32 =head1 COMMAND OPTIONS
38 Print out a usage message.
42 This specifies the input filename to read data from or standard input
43 if this option is not specified.
45 =item B<-out filename>
47 specifies the output filename to write to or standard output by
52 the input key file, by default it should be an RSA private key.
54 =item B<-keyform PEM|DER|ENGINE>
56 the key format PEM, DER or ENGINE.
60 the input file is an RSA public key.
64 the input is a certificate containing an RSA public key.
68 sign the input data and output the signed result. This requires
73 verify the input data and output the recovered data.
77 encrypt the input data using an RSA public key.
81 decrypt the input data using an RSA private key.
83 =item B<-pkcs, -oaep, -ssl, -raw>
85 the padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP,
86 special padding used in SSL v2 backwards compatible handshakes,
87 or no padding, respectively.
88 For signatures, only B<-pkcs> and B<-raw> can be used.
92 hex dump the output data.
96 asn1parse the output data, this is useful when combined with the
103 B<rsautl> because it uses the RSA algorithm directly can only be
104 used to sign or verify small pieces of data.
108 Sign some data using a private key:
110 openssl rsautl -sign -in file -inkey key.pem -out sig
112 Recover the signed data
114 openssl rsautl -verify -in sig -inkey key.pem
116 Examine the raw signed data:
118 openssl rsautl -verify -in file -inkey key.pem -raw -hexdump
120 0000 - 00 01 ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
121 0010 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
122 0020 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
123 0030 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
124 0040 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
125 0050 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
126 0060 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
127 0070 - ff ff ff ff 00 68 65 6c-6c 6f 20 77 6f 72 6c 64 .....hello world
129 The PKCS#1 block formatting is evident from this. If this was done using
130 encrypt and decrypt the block would have been of type 2 (the second byte)
131 and random padding data visible instead of the 0xff bytes.
133 It is possible to analyse the signature of certificates using this
134 utility in conjunction with B<asn1parse>. Consider the self signed
135 example in certs/pca-cert.pem . Running B<asn1parse> as follows yields:
137 openssl asn1parse -in pca-cert.pem
139 0:d=0 hl=4 l= 742 cons: SEQUENCE
140 4:d=1 hl=4 l= 591 cons: SEQUENCE
141 8:d=2 hl=2 l= 3 cons: cont [ 0 ]
142 10:d=3 hl=2 l= 1 prim: INTEGER :02
143 13:d=2 hl=2 l= 1 prim: INTEGER :00
144 16:d=2 hl=2 l= 13 cons: SEQUENCE
145 18:d=3 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
146 29:d=3 hl=2 l= 0 prim: NULL
147 31:d=2 hl=2 l= 92 cons: SEQUENCE
148 33:d=3 hl=2 l= 11 cons: SET
149 35:d=4 hl=2 l= 9 cons: SEQUENCE
150 37:d=5 hl=2 l= 3 prim: OBJECT :countryName
151 42:d=5 hl=2 l= 2 prim: PRINTABLESTRING :AU
153 599:d=1 hl=2 l= 13 cons: SEQUENCE
154 601:d=2 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
155 612:d=2 hl=2 l= 0 prim: NULL
156 614:d=1 hl=3 l= 129 prim: BIT STRING
159 The final BIT STRING contains the actual signature. It can be extracted with:
161 openssl asn1parse -in pca-cert.pem -out sig -noout -strparse 614
163 The certificate public key can be extracted with:
165 openssl x509 -in test/testx509.pem -pubkey -noout >pubkey.pem
167 The signature can be analysed with:
169 openssl rsautl -in sig -verify -asn1parse -inkey pubkey.pem -pubin
171 0:d=0 hl=2 l= 32 cons: SEQUENCE
172 2:d=1 hl=2 l= 12 cons: SEQUENCE
173 4:d=2 hl=2 l= 8 prim: OBJECT :md5
174 14:d=2 hl=2 l= 0 prim: NULL
175 16:d=1 hl=2 l= 16 prim: OCTET STRING
176 0000 - f3 46 9e aa 1a 4a 73 c9-37 ea 93 00 48 25 08 b5 .F...Js.7...H%..
178 This is the parsed version of an ASN1 DigestInfo structure. It can be seen that
179 the digest used was md5. The actual part of the certificate that was signed can
182 openssl asn1parse -in pca-cert.pem -out tbs -noout -strparse 4
184 and its digest computed with:
187 MD5(tbs)= f3:46:9e:aa:1a:4a:73:c9:37:ea:93:00:48:25:08:b5
189 which it can be seen agrees with the recovered value above.
193 L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>
197 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
199 Licensed under the OpenSSL license (the "License"). You may not use
200 this file except in compliance with the License. You can obtain a copy
201 in the file LICENSE in the source distribution or at
202 L<https://www.openssl.org/source/license.html>.