---
name: "Crypt::DSA::Key"
section: "3pm"
platform: "linux"
package: "libcrypt-dsa-perl"
version: "1.19-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Crypt::DSA::Key"
---

# Crypt::DSA::Key(3pm)

DSA key

## NAME

Crypt::DSA::Key - DSA key

## SYNOPSIS

```
    use Crypt::DSA::Key;
    my $key = Crypt::DSA::Key->new;
    $key->p($p);
```

## DESCRIPTION

*Crypt::DSA::Key* contains a DSA key, both the public and private portions. Subclasses of *Crypt::DSA::Key* implement *read* and *write* methods, such that you can store DSA keys on disk, and read them back into your application.

## USAGE

Any of the key attributes can be accessed through combination get/set methods. The key attributes are: *p*, *q*, *g*, *priv\_key*, and *pub\_key*. For example:

```
    $key->p($p);
    my $p2 = $key->p;
```

### $key = Crypt::DSA::Key-\>new(%arg)

Creates a new (empty) key object. All of the attributes are initialized to 0.

Alternately, if you provide the *Filename* parameter (see below), the key will be read in from disk. If you provide the *Type* parameter (mandatory if *Filename* is provided), be aware that your key will actually be blessed into a subclass of *Crypt::DSA::Key*. Specifically, it will be the class implementing the specific read functionality for that type, eg. *Crypt::DSA::Key::PEM*.

Returns the key on success, `"undef"` otherwise. (See *Password* for one reason why *new* might return `"undef"`).

*%arg* can contain:

- •

  Type

  The type of file where the key is stored. Currently the only option is *PEM*, which indicates a PEM file (optionally encrypted, ASN.1-encoded object). Support for reading/writing PEM files comes from *Convert::PEM*; if you don't have this module installed, the *new* method will die.

  This argument is mandatory, *if* you're either reading the file from disk (ie. you provide a *Filename* argument) or you've specified the *Content* argument.

- •

  Filename

  The location of the file from which you'd like to read the key. Requires a *Type* argument so the decoder knows what type of file it is.  You can't specify *Content* and *Filename* at the same time.

- •

  Content

  The serialized version of the key.  Requires a *Type* argument so the decoder knows how to decode it.  You can't specify *Content* and *Filename* at the same time.

- •

  Password

  If your key file is encrypted, you'll need to supply a passphrase to decrypt it. You can do that here.

  If your passphrase is incorrect, *new* will return `"undef"`.

### $key-\>write(%arg)

Writes a key (optionally) to disk, using a format that you define with the *Type* parameter.

If your *$key* object has a defined *priv\_key* (private key portion), the key will be written as a DSA private key object; otherwise, it will be written out as a public key. Note that not all serialization mechanisms can produce public keys in this version--currently, only PEM public keys are supported.

*%arg* can include:

- •

  Type

  The type of file format that you wish to write. *PEM* is one example (in fact, currently, it's the only example).

  This argument is mandatory, *unless* your *$key* object is already blessed into a subclass (eg. *Crypt::DSA::Key::PEM*), and you wish to write the file using the same subclass.

- •

  Filename

  The location of the file on disk where you want the key file to be written.

- •

  Password

  If you want the key file to be encrypted, provide this argument, and the ASN.1-encoded string will be encrypted using the passphrase as a key.

### $key-\>size

Returns the size of the key, in bits. This is actually the number of bits in the large prime *p*.

## AUTHOR & COPYRIGHTS

Please see the Crypt::DSA manpage for author, copyright, and license information.