14 [B<-keyform PEM|DER|ENGINE>]
31 The B<rsautl> command can be used to sign, verify, encrypt and decrypt
32 data using the RSA algorithm.
40 Print out a usage message.
44 This specifies the input filename to read data from or standard input
45 if this option is not specified.
47 =item B<-out filename>
49 Specifies the output filename to write to or standard output by
54 The input key file, by default it should be an RSA private key.
56 =item B<-keyform PEM|DER|ENGINE>
58 The key format PEM, DER or ENGINE.
62 The input file is an RSA public key.
66 The input is a certificate containing an RSA public key.
70 Sign the input data and output the signed result. This requires
75 Verify the input data and output the recovered data.
79 Encrypt the input data using an RSA public key.
83 Decrypt the input data using an RSA private key.
85 =item B<-rand file...>
87 A file or files containing random data used to seed the random number
89 Multiple files can be specified separated by an OS-dependent character.
90 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
93 =item [B<-writerand file>]
95 Writes random data to the specified I<file> upon exit.
96 This can be used with a subsequent B<-rand> flag.
98 =item B<-pkcs, -oaep, -ssl, -raw>
100 The padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP,
101 special padding used in SSL v2 backwards compatible handshakes,
102 or no padding, respectively.
103 For signatures, only B<-pkcs> and B<-raw> can be used.
107 Hex dump the output data.
111 Parse the ASN.1 output data, this is useful when combined with the
118 B<rsautl> because it uses the RSA algorithm directly can only be
119 used to sign or verify small pieces of data.
123 Sign some data using a private key:
125 openssl rsautl -sign -in file -inkey key.pem -out sig
127 Recover the signed data
129 openssl rsautl -verify -in sig -inkey key.pem
131 Examine the raw signed data:
133 openssl rsautl -verify -in file -inkey key.pem -raw -hexdump
135 0000 - 00 01 ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
136 0010 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
137 0020 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
138 0030 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
139 0040 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
140 0050 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
141 0060 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff ................
142 0070 - ff ff ff ff 00 68 65 6c-6c 6f 20 77 6f 72 6c 64 .....hello world
144 The PKCS#1 block formatting is evident from this. If this was done using
145 encrypt and decrypt the block would have been of type 2 (the second byte)
146 and random padding data visible instead of the 0xff bytes.
148 It is possible to analyse the signature of certificates using this
149 utility in conjunction with B<asn1parse>. Consider the self signed
150 example in certs/pca-cert.pem . Running B<asn1parse> as follows yields:
152 openssl asn1parse -in pca-cert.pem
154 0:d=0 hl=4 l= 742 cons: SEQUENCE
155 4:d=1 hl=4 l= 591 cons: SEQUENCE
156 8:d=2 hl=2 l= 3 cons: cont [ 0 ]
157 10:d=3 hl=2 l= 1 prim: INTEGER :02
158 13:d=2 hl=2 l= 1 prim: INTEGER :00
159 16:d=2 hl=2 l= 13 cons: SEQUENCE
160 18:d=3 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
161 29:d=3 hl=2 l= 0 prim: NULL
162 31:d=2 hl=2 l= 92 cons: SEQUENCE
163 33:d=3 hl=2 l= 11 cons: SET
164 35:d=4 hl=2 l= 9 cons: SEQUENCE
165 37:d=5 hl=2 l= 3 prim: OBJECT :countryName
166 42:d=5 hl=2 l= 2 prim: PRINTABLESTRING :AU
168 599:d=1 hl=2 l= 13 cons: SEQUENCE
169 601:d=2 hl=2 l= 9 prim: OBJECT :md5WithRSAEncryption
170 612:d=2 hl=2 l= 0 prim: NULL
171 614:d=1 hl=3 l= 129 prim: BIT STRING
174 The final BIT STRING contains the actual signature. It can be extracted with:
176 openssl asn1parse -in pca-cert.pem -out sig -noout -strparse 614
178 The certificate public key can be extracted with:
180 openssl x509 -in test/testx509.pem -pubkey -noout >pubkey.pem
182 The signature can be analysed with:
184 openssl rsautl -in sig -verify -asn1parse -inkey pubkey.pem -pubin
186 0:d=0 hl=2 l= 32 cons: SEQUENCE
187 2:d=1 hl=2 l= 12 cons: SEQUENCE
188 4:d=2 hl=2 l= 8 prim: OBJECT :md5
189 14:d=2 hl=2 l= 0 prim: NULL
190 16:d=1 hl=2 l= 16 prim: OCTET STRING
191 0000 - f3 46 9e aa 1a 4a 73 c9-37 ea 93 00 48 25 08 b5 .F...Js.7...H%..
193 This is the parsed version of an ASN1 DigestInfo structure. It can be seen that
194 the digest used was md5. The actual part of the certificate that was signed can
197 openssl asn1parse -in pca-cert.pem -out tbs -noout -strparse 4
199 and its digest computed with:
202 MD5(tbs)= f3:46:9e:aa:1a:4a:73:c9:37:ea:93:00:48:25:08:b5
204 which it can be seen agrees with the recovered value above.
208 L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>
212 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
214 Licensed under the OpenSSL license (the "License"). You may not use
215 this file except in compliance with the License. You can obtain a copy
216 in the file LICENSE in the source distribution or at
217 L<https://www.openssl.org/source/license.html>.