DSA(1) OpenSSL DSA(1)

NAME
       dsa - DSA key processing

SYNOPSIS
       ooppeennssssll ddssaa [-iinnffoorrmm PPEEMM||DDEERR] [-oouuttffoorrmm PPEEMM||DDEERR] [-iinn ffiilleennaammee]
       [-ppaassssiinn aarrgg] [-oouutt ffiilleennaammee] [-ppaassssoouutt aarrgg] [-ddeess] [-ddeess33] [-iiddeeaa]
       [-tteexxtt] [-nnoooouutt] [-mmoodduulluuss] [-ppuubbiinn] [-ppuubboouutt] [-eennggiinnee iidd]

DESCRIPTION
       The ddssaa command processes DSA keys. They can be converted between
       various forms and their components printed out. NNoottee This command uses
       the traditional SSLeay compatible format for private key encryption:
       newer applications should use the more secure PKCS#8 format using the
       ppkkccss88

CCOOMMMMAANNDD OOPPTTIIOONNSS
       -iinnffoorrmm DDEERR||PPEEMM
           This specifies the input format. The DDEERR 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 PPEEMM form is the default format: it consists of the DDEERR format
           base64 encoded with additional header and footer lines. In the case
           of a private key PKCS#8 format is also accepted.

       -oouuttffoorrmm DDEERR||PPEEMM
           This specifies the output format, the options have the same meaning
           as the -iinnffoorrmm option.

       -iinn ffiilleennaammee
           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.

       -ppaassssiinn aarrgg
           the input file password source. For more information about the
           format of aarrgg see the PPAASSSS PPHHRRAASSEE AARRGGUUMMEENNTTSS section in openssl(1).

       -oouutt ffiilleennaammee
           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 nnoott
           be the same as the input filename.

       -ppaassssoouutt aarrgg
           the output file password source. For more information about the
           format of aarrgg see the PPAASSSS PPHHRRAASSEE AARRGGUUMMEENNTTSS section in openssl(1).

       -ddeess||-ddeess33||-iiddeeaa
           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 ddssaa 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.

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

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

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

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

       -ppuubboouutt
           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.

       -eennggiinnee iidd
           specifying an engine (by it's unique iidd string) will cause rreeqq 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.

NNOOTTEESS
       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:

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

EEXXAAMMPPLLEESS
       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)



0.9.7l                            2003-01-30                            DSA(1)