1DSA(1)                              OpenSSL                             DSA(1)
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NAME

6       dsa - DSA key processing
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SYNOPSIS

9       openssl dsa [-inform PEM|DER] [-outform PEM|DER] [-in filename]
10       [-passin arg] [-out filename] [-passout arg] [-des] [-des3] [-idea]
11       [-text] [-noout] [-modulus] [-pubin] [-pubout] [-engine id]
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DESCRIPTION

14       The dsa command processes DSA keys. They can be converted between
15       various forms and their components printed out. Note This command uses
16       the traditional SSLeay compatible format for private key encryption:
17       newer applications should use the more secure PKCS#8 format using the
18       pkcs8
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COMMAND OPTIONS

21       -inform DER|PEM
22           This specifies the input format. The DER option with a private key
23           uses an ASN1 DER encoded form of an ASN.1 SEQUENCE consisting of
24           the values of version (currently zero), p, q, g, the public and
25           private key components respectively as ASN.1 INTEGERs. When used
26           with a public key it uses a SubjectPublicKeyInfo structure: it is
27           an error if the key is not DSA.
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29           The PEM form is the default format: it consists of the DER format
30           base64 encoded with additional header and footer lines. In the case
31           of a private key PKCS#8 format is also accepted.
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33       -outform DER|PEM
34           This specifies the output format, the options have the same meaning
35           as the -inform option.
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37       -in filename
38           This specifies the input filename to read a key from or standard
39           input if this option is not specified. If the key is encrypted a
40           pass phrase will be prompted for.
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42       -passin arg
43           the input file password source. For more information about the
44           format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
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46       -out filename
47           This specifies the output filename to write a key to or standard
48           output by is not specified. If any encryption options are set then
49           a pass phrase will be prompted for. The output filename should not
50           be the same as the input filename.
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52       -passout arg
53           the output file password source. For more information about the
54           format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
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56       -des|-des3|-idea
57           These options encrypt the private key with the DES, triple DES, or
58           the IDEA ciphers respectively before outputting it. A pass phrase
59           is prompted for.  If none of these options is specified the key is
60           written in plain text. This means that using the dsa utility to
61           read in an encrypted key with no encryption option can be used to
62           remove the pass phrase from a key, or by setting the encryption
63           options it can be use to add or change the pass phrase.  These
64           options can only be used with PEM format output files.
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66       -text
67           prints out the public, private key components and parameters.
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69       -noout
70           this option prevents output of the encoded version of the key.
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72       -modulus
73           this option prints out the value of the public key component of the
74           key.
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76       -pubin
77           by default a private key is read from the input file: with this
78           option a public key is read instead.
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80       -pubout
81           by default a private key is output. With this option a public key
82           will be output instead. This option is automatically set if the
83           input is a public key.
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85       -engine id
86           specifying an engine (by its unique id string) will cause dsa to
87           attempt to obtain a functional reference to the specified engine,
88           thus initialising it if needed. The engine will then be set as the
89           default for all available algorithms.
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NOTES

92       The PEM private key format uses the header and footer lines:
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94        -----BEGIN DSA PRIVATE KEY-----
95        -----END DSA PRIVATE KEY-----
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97       The PEM public key format uses the header and footer lines:
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99        -----BEGIN PUBLIC KEY-----
100        -----END PUBLIC KEY-----
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EXAMPLES

103       To remove the pass phrase on a DSA private key:
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105        openssl dsa -in key.pem -out keyout.pem
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107       To encrypt a private key using triple DES:
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109        openssl dsa -in key.pem -des3 -out keyout.pem
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111       To convert a private key from PEM to DER format:
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113        openssl dsa -in key.pem -outform DER -out keyout.der
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115       To print out the components of a private key to standard output:
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117        openssl dsa -in key.pem -text -noout
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119       To just output the public part of a private key:
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121        openssl dsa -in key.pem -pubout -out pubkey.pem
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SEE ALSO

124       dsaparam(1), gendsa(1), rsa(1), genrsa(1)
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1281.0.1e                            2013-02-11                            DSA(1)
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