5 dsa - DSA key processing
35 The B<dsa> command processes DSA keys. They can be converted between various
36 forms and their components printed out. B<Note> This command uses the
37 traditional SSLeay compatible format for private key encryption: newer
38 applications should use the more secure PKCS#8 format using the B<pkcs8>
40 =head1 COMMAND OPTIONS
46 Print out a usage message.
48 =item B<-inform DER|PEM>
50 This specifies the input format. The B<DER> option with a private key uses
51 an ASN1 DER encoded form of an ASN.1 SEQUENCE consisting of the values of
52 version (currently zero), p, q, g, the public and private key components
53 respectively as ASN.1 INTEGERs. When used with a public key it uses a
54 SubjectPublicKeyInfo structure: it is an error if the key is not DSA.
56 The B<PEM> form is the default format: it consists of the B<DER> format base64
57 encoded with additional header and footer lines. In the case of a private key
58 PKCS#8 format is also accepted.
60 =item B<-outform DER|PEM>
62 This specifies the output format, the options have the same meaning as the
67 This specifies the input filename to read a key from or standard input if this
68 option is not specified. If the key is encrypted a pass phrase will be
73 the input file password source. For more information about the format of B<arg>
74 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
76 =item B<-out filename>
78 This specifies the output filename to write a key to or standard output by
79 is not specified. If any encryption options are set then a pass phrase will be
80 prompted for. The output filename should B<not> be the same as the input
85 the output file password source. For more information about the format of B<arg>
86 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
88 =item B<-aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea>
90 These options encrypt the private key with the specified
91 cipher before outputting it. A pass phrase is prompted for.
92 If none of these options is specified the key is written in plain text. This
93 means that using the B<dsa> utility to read in an encrypted key with no
94 encryption option can be used to remove the pass phrase from a key, or by
95 setting the encryption options it can be use to add or change the pass phrase.
96 These options can only be used with PEM format output files.
100 prints out the public, private key components and parameters.
104 this option prevents output of the encoded version of the key.
108 this option prints out the value of the public key component of the key.
112 by default a private key is read from the input file: with this option a
113 public key is read instead.
117 by default a private key is output. With this option a public
118 key will be output instead. This option is automatically set if the input is
123 specifying an engine (by its unique B<id> string) will cause B<dsa>
124 to attempt to obtain a functional reference to the specified engine,
125 thus initialising it if needed. The engine will then be set as the default
126 for all available algorithms.
132 The PEM private key format uses the header and footer lines:
134 -----BEGIN DSA PRIVATE KEY-----
135 -----END DSA PRIVATE KEY-----
137 The PEM public key format uses the header and footer lines:
139 -----BEGIN PUBLIC KEY-----
140 -----END PUBLIC KEY-----
144 To remove the pass phrase on a DSA private key:
146 openssl dsa -in key.pem -out keyout.pem
148 To encrypt a private key using triple DES:
150 openssl dsa -in key.pem -des3 -out keyout.pem
152 To convert a private key from PEM to DER format:
154 openssl dsa -in key.pem -outform DER -out keyout.der
156 To print out the components of a private key to standard output:
158 openssl dsa -in key.pem -text -noout
160 To just output the public part of a private key:
162 openssl dsa -in key.pem -pubout -out pubkey.pem
166 L<dsaparam(1)>, L<gendsa(1)>, L<rsa(1)>,
171 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
173 Licensed under the OpenSSL license (the "License"). You may not use
174 this file except in compliance with the License. You can obtain a copy
175 in the file LICENSE in the source distribution or at
176 L<https://www.openssl.org/source/license.html>.