Erase or Shred Hard Disk Drives

Is it more secure to erase or shred hard drives for data sanitization? NIST 800-88 suggests physically shredding hard drives is the most secure.  A study by the students at the Massachusetts Institute of Technology (MIT) may suggest the same.

The MIT students report called “A Remembrance of Data Passed: A Study of Disk Sanitization Practices,” analyzed 158 disk drives purchased through eBay Inc.’s online auction site, at computer stores, salvage companies and swap meets.  The study showed: 74% of the drives contained old data that could be recovered and read, 17% contained fully installed and functional operating systems with user data that required no particular effort to recover and , 9% had been properly cleaned.

The National Institute of Standards and Technology has developed guidelines for Computer Security and Media Sanitization (NIST 800-88). These guidelines have defined the most secure way to destroy data contained on computer hard drives and data backup tapes. Organizations regulated by data privacy laws such as HIPAA, HITECH and GLBA should be aware of these hard drive destruction guidelines when disposing of IT equipment such as servers and computers.

Shredded Hard Drives


Ensuring that confidential data is not released outside the company is the main concern when embarking on a digital media sanitization project. Watch the hard drive shredding video and see if you agree with NIST 800-88 digital media sanitization guidelines.  The three media sanitization methods described in NIST 800-88 are:

Digital Media Sanitization Methods

IRS Hard Drive Sanitization Requirements

ERASING is appropriate for removing information from digital media that is considered low level information. The erasing, or wiping, process is approved for protection against simple non-evasive recovery techniques. This process consists of using hardware or software products to write data over the current confidential information. Basically, the overwriting, or ‘wiping’ software, will write 0’s and 1’s over the existing data on the hard drive. Overwriting or wiping is NOT erasing, computer hard drives cannot be erased only overwritten.

DEGUASSING is the second level of security when destroying digital data. The technique of degaussing – applying a strong magnetic field to the hard drive – would fall under the Purge method.  Purging data from computer hard drive should make data recovery infeasible using state of the art laboratory techniques.

SHREDDING, incinerating or crushing is the most secure form of digital media data destruction. This method renders data recovery infeasible using state of the art laboratory techniques and results in the inability for the drive to work at all.

IRS Publication 1075 clarifies the implementation of electronic media sanitization. In general, IRS 1075 follows the guidelines set forth in NIST SP 800-88, Guidelines for Media Sanitization. However, IRS 1075 looks at two specific factors in determining action, 1) whether or not the media is to be reused by the agency, and2) Whether or not the media will be leaving agency control

The IRS policy provides specific guidance on techniques that should be used for Federal Tax Information (FTI) by clearing, purging and destroying the FTI based on the type of media housing the FTI. Verifying the selected information sanitization and disposal process is an essential step in maintaining confidentiality. Generally, destruction should be witnessed by an agency employee.

The decision to erase or physically destroy hard drives should be based on your organization’s policies and procedures governing data security and destruction. Many business and organizations are now required to have a written Identity Theft Prevention Program per the Federal Trade Commission’s Red Flags Rule.