Results 1 to 6 of 6
  1. #1
    iNET Interactive
    Join Date
    Jan 2010
    Location
    Seattle, WA, USA
    Posts
    376
    Thanks
    1
    Thanked 29 Times in 24 Posts



    LANGALIST PLUS

    Is data-wiping deleted files worthwhile?


    By Fred Langa

    Data-wiping — securely overwriting deleted files with random ones and zeros — makes deleted data much harder to recover. But is it worth the hassle?In most cases, the answer is no. There are much simpler methods for making sure deleted files are truly gone.

    The full text of this column is posted at WindowsSecrets.com/2010/10/14/05 (paid content, opens in a new window/tab).

    Columnists typically cannot reply to comments here, but do incorporate the best tips into future columns.
    Last edited by revia; 2011-01-19 at 15:04.

  2. #2
    Star Lounger
    Join Date
    Dec 2009
    Location
    Syracuse, NY USA
    Posts
    50
    Thanks
    0
    Thanked 2 Times in 2 Posts
    Defragging overwrites the areas that the defragged data was moved to, but the new vacant blocks/clusters still contain data. A defrag leaves data in the now free space where the data was before the defrag, or where data was moved temporarily while making enough free contiguous space to defrag a file.

    Have you ever watched a defragger in operation, including the map of disk free and occupied blocks before and after the defrag?

    If a copy of “live” data is on the system, data wiping won’t help. Instead you should be thinking about physical security of the machine, strong passwords, securing network access, and encryption. It would easy for a data thief to remove the hard drive. If the data is not encrypted then the thief could harvest the data at his leisure, or make a clone copy and return the disk, which would make it very difficult to suspect or detect the theft. (I once had a computer that will tell you that the case has been opened during BIOS POST, but haven’t seen this feature for a long time.)

    If the system is being retired or transferred to another entity (donated, sold, recycled, etc.) then it might make sense to do a wipe.

    Data wiping consists of overwriting disk blocks with one or multiple patterns.
    http://en.wikipedia.org/wiki/Data_remanence: according to the 2006 NIST Special Publication 800-88 (p. 7): "Studies have shown that most of today’s media can be effectively cleared by one overwrite" and "for ATA disk drives manufactured after 2001 (over 15 GB) the terms clearing and purging have converged." An analysis by Wright et al. of recovery techniques, including magnetic force microscopy, also concludes that a single wipe is all that is required for modern drives. They point out that the long time required for multiple wipes "has created a situation where many organizations [sic] ignore the issue all together – resulting in data leaks and loss.”

    RAID, SSDs (Solid State Disk, especially with write balancing), “bad blocks”, journaling file systems and other advanced storage systems may make data overwrite difficult or impossible.

    If the drive ever held government data, the contract may specify disposal requirements or one of the government standards may apply.

    There were about 7 different government standards for data destruction when I worked on a project with secure erase requirements a few years ago on an aircraft system that would hold classified data. We chose a solid state disk drive that supported several MIL STD secure erase command sequences, including one appropriate for the system. (The vendor even included a mode that would electronically destroy the storage chips.) Once the drive was told to secure erase, it went offline and would no longer respond until the secure erase finished. Even power cycling would not interrupt the offline secure erase.

    Current government requirements require degaussing or destruction of the media. (per http://en.wikipedia.org/wiki/Data_remanence)

  3. #3
    New Lounger
    Join Date
    Dec 2009
    Location
    Maryland
    Posts
    3
    Thanks
    0
    Thanked 0 Times in 0 Posts
    re: Networking via your electrical wiring
    Will the power line networking adapters work across split phase wiring?
    For example to use X-10 you need a special device for the signal to reach the other circuits.

  4. #4
    New Lounger
    Join Date
    Oct 2010
    Location
    Rhode Island
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by bellrama View Post
    re: Networking via your electrical wiring
    Will the power line networking adapters work across split phase wiring?
    For example to use X-10 you need a special device for the signal to reach the other circuits.
    [This "networking via electrical wiring" thread needs to be a separate thread from data-wiping one's files]

    I asked a very similar question to the support staff at Actiontec regarding AC hum and working across different circuits and got this response:

    "Negative. Those issues exist with all power line adapters as they are using the home wiring as a substitue [sic] for network cable.
    The breaker in your home is not a network device, it will never be capable of sending an IP address from one circuit to the other circuit."

    I hope Fred's equipment is all on the same circuit.

  5. #5
    Super Moderator Deadeye81's Avatar
    Join Date
    Dec 2009
    Location
    North Carolina, USA
    Posts
    2,654
    Thanks
    7
    Thanked 113 Times in 97 Posts
    Hello Ty and welcome to the Lounge!

    Any topic covered by the columnist is fair to comment on in the Windows Secrets Columns forum. It is intended to be a means of feedback to the Newsletter columnists. In that regard it is unique in the Windows Secrets Forums.
    Deadeye81

    "We make a living by what we get, we make a life by what we give." Sir Winston Churchill

  6. #6
    Lounger
    Join Date
    Dec 2009
    Posts
    38
    Thanks
    0
    Thanked 4 Times in 3 Posts
    Quote Originally Posted by Ty Davis View Post
    [This "networking via electrical wiring" thread needs to be a separate thread from data-wiping one's files]

    I asked a very similar question to the support staff at Actiontec regarding AC hum and working across different circuits and got this response:

    "Negative. Those issues exist with all power line adapters as they are using the home wiring as a substitue [sic] for network cable.
    The breaker in your home is not a network device, it will never be capable of sending an IP address from one circuit to the other circuit."

    I hope Fred's equipment is all on the same circuit.
    What a load of nonsense. Your breaker is a bit of wire and it does NOT stop the powerline signal.

    I was saddened to see Fred mention powerline adaptors. There are HUGE EMC interference problems with these, as a quick web search will reveal. Existing ones block out shortwave reception and the newer Gigabit types threaten to do the same with normal VHF FM reception. Power wiring is unbalanced and not designed to transmit RF signals, being effectively a big aerial. More information at http://www.mds975.co.uk/Content/amat...erference.html and http://www.ukqrm.org/

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •