Provided by: openssl_1.0.1f-1ubuntu2_amd64
dsa - DSA key processing
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]
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
-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 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.
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-----
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