OpenSL                                             dsa(1openssl)



NAME
     dsa - DSA key processing

SYNOPSIS
     openssl dsa [-inform PEMDER] [-outform PEMDER] [-in
     filename] [-passin arg] [-out filename] [-passout arg]
     [-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 SLeay compatible format
     for private key encryption: newer applications should use
     the more secure PKCS#8 format using the pkcs8

COMAND OPTIONS
     -inform DERPEM
         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 DERPEM
         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 PAS 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.




OpenSL-0.9.8       Last change: Oct 11 2005                    1






OpenSL                                             dsa(1openssl)



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

     -des-des3-idea
         These options encrypt the private key with the DES,
         triple DES, or the IDEA ciphers respectively 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 it's unique id string) will
         cause req 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-----





OpenSL-0.9.8       Last change: Oct 11 2005                    2






OpenSL                                             dsa(1openssl)



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

      -----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)


























OpenSL-0.9.8       Last change: Oct 11 2005                    3