---
name: "Mail::DKIM::SigningFilter"
section: "3pm"
platform: "linux"
package: "libmail-dkim-perl"
version: "0.19-3"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/Mail::DKIM::SigningFilter"
---

# Mail::DKIM::SigningFilter(3pm)

signs email with a DKIM signature

## NAME

Mail::DKIM::SigningFilter - signs email with a DKIM signature

## SYNOPSIS

```
  use Mail::DKIM::SigningFilter;
```

```
  # create a signing filter object
  my $dkim = Mail::DKIM::SigningFilter->new_object(
                  Algorithm => "rsa-sha1",
                  Method => "nowsp",
                  Domain => "example.org",
                  Selector => "selector1",
                  KeyFile => "private.key");
             );
```

```
  # read an email from stdin, pass it into the signing filter.
  # the resulting message will be output on STDOUT.
  while (<STDIN>)
  {
      # remove local line terminators
      chomp;
      s/\015$//;
```

```
      # use SMTP line terminators
      $dkim->PRINT("$_\015\012");
  }
  $dkim->CLOSE;
```

## DESCRIPTION

The "Signing Filter" is fed an email address and outputs to the specified file handle the same message with a DKIM-Signature prepended.

The steps done are:\
  1\. Parse all headers\
  2\. Modify headers if desired (e.g. remove existing DKIM-Signature?)\
  3\. Determine signature parameters\
  4\. Feed (possibly modified) headers into selected canonicalization/algorithm\
  5\. Receive rest of message and feed it into canonicalization/algorithm\
  6\. Generate signature\
  7\. Write prepended DKIM-Signature header\
  8\. Write (possibly modified in step 2) headers\
  9\. Write body