Enhanced version of dd for forensics and security.
Copy a disk to a raw image file and hash the image using SHA256
dcfldd if=/dev/disk_device of=file.img hash=sha256 hashlog=file.hash
Copy a disk to a raw image file, hashing each 1 GB chunk
dcfldd if=/dev/disk_device of=file.img hash=sha512|sha384|sha256|sha1|md5 hashlog=file.hash hashwindow=1G