DSA(1) OpenSSL DSA(1)
NAME
dsa - DSA key processing
SYNOPSIS
openssl dsa [-inform PEM|DER] [-outform PEM|DER] [-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 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.
-passout arg
the output file password source. For more information about the format of arg see the PASS 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 KEY---------END
-----END DSA PRIVATE KEY-----The KEY----The
The PEM public key format uses the header and footer lines:
-----BEGIN PUBLIC KEY----------END KEY---------END
-----END PUBLIC KEY-----EXAMPLES KEY----EXAMPLES
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)
0.9.7l 2003-01-30 DSA(1)
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