Data Sanitization Standard
Purpose
The purpose of this standard is to provide instructions on proper sanitization of data in
both electronic and paper form. This standard also provides instruction on secure disposal
of electronic storage media.
Scope
This standard applies to any electronic information storage or paper-based media
containing sensitive or confidential data repurposed or transferred outside of Michigan
Tech. This standard also applies to all University personnel who are responsible for the
sanitization of potentially sensitive information and/or the disposal of electronic storage
media.
Definitions
The National Institute of Standards and Technology (NIST) has defined four methods of
data sanitization. These four methods are as follows:
• Disposal is defined as the act of discarding media with no other sanitization
considerations. Examples of Disposal include discarding paper in a recycling
container, deleting electronic documents using standard file deletion methods and
discarding electronic storage media in a standard trash receptacle.
• Clearing is defined as a level of sanitization that renders media unreadable through
normal means. Clearing is typically accomplished through an overwriting process
that replaces actual data with 0’s or random characters. Clearing prevents data
from being recovered using standard disk and file recovery utilities.
• Purging is defined as a more advanced level of sanitization that renders media
unreadable even through an advanced laboratory attack. In traditional thinking,
Purging consists of using specialized utilities that repeatedly overwrite data;
however, with advancements in electronic storage media, the definitions of Clearing
and Purging are converging. For example, purging a hard drive manufactured after
2001 only requires a single overwrite. For the purpose of this Guideline, Clearing
and Purging will be considered the same. Degaussing is also an acceptable method
of purging electronic storage media; however, this typically renders the media
unusable in the future.
• Destroying is defined as rendering media unusable. Destruction techniques include
but are not limited to disintegration, incineration, pulverizing, shredding and
melting. This is a common sanitization method for single-write storage media such
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as a CD or DVD for which other sanitization methods would be ineffective. This is
also a common practice when permanently discarding hard drives.
• Electronic Storage Media is defined as any electronic device that can be used to store
data. This includes but is not limited to internal and external hard drives, CDs,
DVDs, Floppy Disks, USB drives, ZIP disks, magnetic tapes and SD cards.
• Non-public Information is defined as any information that is classified as
Confidential (Tier I) or Internal/Private (Tier II) according to the Information
Security Plan.
Regulatory Requirements
The Family Educational Rights and Privacy Act (FERPA), the Gramm-Leach-Bliley Act
(GLBA), the Health Insurance Portability and Accountability Act of 1996 (HIPAA), and
Payment Card Industry Data Security Standards (PCI DSS) require formal documentation of
disposal procedures to ensure specific types of information is properly sanitized prior to
being discarded.
Guidelines
The following are recommendations for when data sanitization should occur:
• All paper-based media should be disposed of when it is no longer necessary for
business use, provided that the disposal does not conflict with University data
retention policies or any regulatory requirements. Questions about retention
requirements should be directed toward the appropriate data owner.
• All electronic storage media should be sanitized when it is no longer necessary for
business use, provided that the sanitization does not conflict with University data
retention policies, or any regulatory requirements. Questions about retention
requirements should be directed toward the appropriate data owner.
• All electronic storage media should be sanitized prior to sale, donation or transfer of
ownership. A transfer of ownership may include transitioning media to someone in
your department with a different role, relinquishing media to another department,
or replacing media as part of a lease agreement.
The following are recommended for sanitization and disposal of paper-based media:
• Cross shredding should be used for Clearing and Purging of paper-based media.
• A third-party document destruction services should be leveraged for destroying
paper-based media. A Certificate of Destruction should be requested, as evidence
that documents were destroyed, and retained for future reference.
The following are recommended for sanitization and disposal of Electronic Storage Media:
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• Cross shredding should be used for Destroying non-writeable CDs, DVDs and Floppy
Disks.
• In situations where a third-party warranty or repair contract prevents proper
sanitization of Electronic Storage Media, ITS should be contacted for further
guidance.
Data Removal and Destruction Management
It is important to maintain an effective method of managing the process of data destruction.
This ensures that all media requiring cleaning or destruction is correctly organized and
properly audited. Please contact ITS for further instruction.
A record of all destruction/disposal of all sensitive data should be retained permanently.
The log should contain a section for destruction or removal certificates; these provide
evidence guaranteeing the destruction or sanitization of the media and the date on which
the destruction occurred.
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