Skip to content


dc3dd is a patched version of GNU dd with added features for computer forensics. It was developed at the DoD Cyber Crime Center by Jesse Kornblum. The first release, corresponding to Coreutils version 6.9.91, was published on 1 Feb 2008.

Comparison to GNU dd

The following features are available in dc3dd that are not found in GNU dd:

  • On the fly hashing with multiple algorithms (md5, SHA-1, SHA-256, and SHA-512) with variable sized piecewise hashing
  • Able to write errors directly to a file
  • Combined error log. Groups errors together (e.g. Had 1,023 'Input/ouput errors' between blocks 17-233')
  • Pattern wiping. Wipe output files with a single hex digit or a text pattern
  • Verify mode
  • Progress reports. See the progress of the operation while it's running
  • Split output. Able to split output files into fixed size chunks

The following changes to GNU dd's behavior were made:

  • On a partial read, the whole block is wiped with zeros. This allows for repeatable reads/hashes of a drive with errors.

Comparison to dcfldd

Although there are definitely similarities between dc3dd and dcfldd, the programs are based on slightly different code bases and have different feature sets. dcfldd is a fork of GNU dd, whereas dc3dd is a patch to the current version. This means that dc3dd will be updated every time GNU dd is updated, whereas dcfldd has its own release schedule. Certain features added to GNU dd after dcfldd forked, such as direct input/output mode, are not found in dcfldd.

On the other hand, dcfldd supports more hashing algorithms than dc3dd, allows the user greater control over how hashes are displayed, supports wiping output files with random patterns, and is supported on the Cygwin platform.

See Also