/usr/man/cat.1/openssl-dsa.1

DSA(1)                       OpenSSL                       DSA(1)

NAME

     openssl-dsa, dsa - DSA key processing

SYNOPSIS

     openssl dsa [-inform PEM|DER] [-outform PEM|DER] [-in
     filename] [-passin arg] [-out filename] [-passout arg]
     [-aes128] [-aes192] [-aes256] [-camellia128] [-camellia192]
     [-camellia256] [-des] [-des3] [-idea] [-text] [-noout]
     [-modulus] [-pubin] [-pubout] [-engine id]

DESCRIPTION

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

COMMAND OPTIONS

     -inform DER|PEM
         This specifies the input format. The DER option with a
         private key uses an ASN1 DER encoded form of an ASN.1
         SEQUENCE consisting of the values of version (currently
         zero), p, q, g, the public and private key components
         respectively as ASN.1 INTEGERs. When used with a public
         key it uses a SubjectPublicKeyInfo structure: it is an
         error if the key is not DSA.

         The PEM form is the default format: it consists of the
         DER format base64 encoded with additional header and
         footer lines. In the case of a private key PKCS#8 format
         is also accepted.

     -outform DER|PEM
         This specifies the output format, the options have the
         same meaning as the -inform option.

     -in filename
         This specifies the input filename to read a key from or
         standard input if this option is not specified. If the
         key is encrypted a pass phrase will be prompted for.

     -passin arg
         the input file password source. For more information
         about the format of arg see the PASS PHRASE ARGUMENTS
         section in openssl(1).

     -out filename
         This specifies the output filename to write a key to or
         standard output by is not specified. If any encryption
         options are set then a pass phrase will be prompted for.
         The output filename should not be the same as the input
         filename.

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DSA(1)                       OpenSSL                       DSA(1)

     -passout arg
         the output file password source. For more information
         about the format of arg see the PASS PHRASE ARGUMENTS
         section in openssl(1).

     -aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea
         These options encrypt the private key with the specified
         cipher before outputting it. A pass phrase is prompted
         for.  If none of these options is specified the key is
         written in plain text. This means that using the dsa
         utility to read in an encrypted key with no encryption
         option can be used to remove the pass phrase from a key,
         or by setting the encryption options it can be use to
         add or change the pass phrase.  These options can only
         be used with PEM format output files.

     -text
         prints out the public, private key components and
         parameters.

     -noout
         this option prevents output of the encoded version of
         the key.

     -modulus
         this option prints out the value of the public key
         component of the key.

     -pubin
         by default a private key is read from the input file:
         with this option a public key is read instead.

     -pubout
         by default a private key is output. With this option a
         public key will be output instead. This option is
         automatically set if the input is a public key.

     -engine id
         specifying an engine (by its unique id string) will
         cause dsa to attempt to obtain a functional reference to
         the specified engine, thus initialising it if needed.
         The engine will then be set as the default for all
         available algorithms.

NOTES

     The PEM private key format uses the header and footer lines:

      -----BEGIN DSA PRIVATE KEY-----
      -----END DSA PRIVATE KEY-----

     The PEM public key format uses the header and footer lines:

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DSA(1)                       OpenSSL                       DSA(1)

      -----BEGIN PUBLIC KEY-----
      -----END PUBLIC KEY-----

EXAMPLES

     To remove the pass phrase on a DSA private key:

      openssl dsa -in key.pem -out keyout.pem

     To encrypt a private key using triple DES:

      openssl dsa -in key.pem -des3 -out keyout.pem

     To convert a private key from PEM to DER format:

      openssl dsa -in key.pem -outform DER -out keyout.der

     To print out the components of a private key to standard
     output:

      openssl dsa -in key.pem -text -noout

     To just output the public part of a private key:

      openssl dsa -in key.pem -pubout -out pubkey.pem

SEE ALSO

     dsaparam(1), gendsa(1), rsa(1), genrsa(1)

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See also dsa(1)