NZISM — New Zealand Information Security Manual

The New Zealand Information Security Manual (NZISM) establishes information-security controls and guidance for protecting New Zealand Government information and systems.

The NZISM is based on security threat and risk assessment and provides:

• Essential Or Baseline Controls
• Additional Good-Practice Controls
• Recommended Practices
• Security Implementation Guidance
• Information-Security Assurance Requirements
• Media-Management Requirements
• Decommissioning And Disposal Controls

The current NZISM includes dedicated provisions for media and IT equipmentsanitization, making it directly relevant to secure data erasure, storage-media reuse and controlled disposal.

The New Zealand NCSC continues to maintain and update NZISM.

The NCSC announced NZISM v3.9 in May 2025, with updates to several chapters and sections.

For media sanitization, the current NZISM material identifies Section 13.4 — Media and IT EquipmentSanitization and related disposal controls in Section 13.6.

NZISM treats sanitization as a security process rather than simply deleting files or formatting a device.

The current NZISM states that sanitization procedures are intended to prevent unauthorized access to classified information and that approved sanitization methods should provide a high level of assurance that remnant data is not left on the media.

The manual also specifically requires that an overwrite process be read back to verify successful completion. If sanitization cannot be successfully completed, destruction is required.

1. 01Sanitize
2. 02Read Back
3. 03Verify
4. 04Accept

If the sanitization process cannot be successfully completed:

This is one of the most important technical distinctions for the DSP website.

NZISM does not mean:

• Always Use One Pass
• Always Use Three Passes
• Always Use Seven Passes
• Always Use Random Data
• Always Use Zeros
• Always Use A Particular Legacy Overwrite Pattern

Instead, NZISM provides media-specific security controls and sanitization requirements.

The appropriate treatment depends on:

• Media Type
• Storage Technology
• Classification
• Device Condition
• Intended Reuse
• Sanitization Capability
• Verification Result
• Disposal Requirements

The current NZISM explicitly distinguishes between different categories of media and requires destruction for media that cannot be effectively sanitized.

DSP provides a dedicated NZISM Sanitization Method through the DSP Sanitization Engine.

Identify

Identify the storage device.

Classify

Determine media type, storage technology and relevant device characteristics.

Assess

Assess whether the device can be successfully sanitized using an applicable method.

Select

Select the NZISM sanitization profile.

Execute

Run the applicable sanitization operation through the DSP Sanitization Engine.

Verify

Read back and verify the sanitization result.

Validate

Determine whether the device satisfies the defined sanitization requirements.

Document

Record the operation, device and verification information.

Certify

Generate an audit-ready DSP sanitization certificate.

If Sanitization Fails

Flag the device for the applicable destruction/disposal workflow.

The current NZISM contains specific controls for non-volatile magnetic media.

For applicable magnetic media, the historical/current NZISM framework has differentiated requirements according to the age/capacity of the media.

The current manual's sanitization requirements should therefore be implemented according to the applicable NZISM version, media classification and organizational policy, rather than converting NZISM into a generic “three-pass” marketing claim.

This is particularly important because older NZISM versions contained explicit magnetic-media overwrite rules that differed according to media characteristics. The current NZISM should be treated as the controlling reference for current implementations.

One of the strongest technical characteristics of the NZISM sanitization approach is its explicit emphasis on read-back verification.

The current NZISM states that when sanitizing media, it is necessary to read back the contents to verify that the overwrite process completed successfully.

DSP can therefore record:

• Sanitization Completion
• Verification Status
• Read-Back Result
• Read Errors
• Write Errors
• Failed Regions
• Device Response
• Validation Result

1. 01Write / Sanitize
2. 02Read Back
3. 03Compare / Verify
4. 04Pass Or Fail

This provides stronger evidence than a simple application status such as “Wipe Complete.”

NZISM takes a clear position when sanitization cannot be successfully completed.

The current NZISM states that if the sanitization process cannot be successfully completed, destruction will be necessary.

This is particularly relevant for damaged or inaccessible storage.

DSP can identify conditions such as:

• Bad Sectors
• Read Failures
• Write Failures
• Unstable Sectors
• Inaccessible Regions
• Device Communication Errors
• Sanitization Failures

The result can then be documented for an appropriate destroy / dispose decision.

This is a major technical distinction.

Current NZISM specifically identifies certain storage types that cannot be effectively sanitized under its applicable controls and therefore must be destroyed prior to disposal.

The current Section 13.4 lists:

• Flash Memory
• Solid-State Storage Devices
• Hybrid Storage Devices
• Rom
• Prom
• Eprom
• Eeprom
• Optical Discs
• Microfilm
• Microfiche
• Certain Faulty Magnetic Media

among media requiring destruction where effective sanitization is not possible.

Therefore, the DSP website should not claim that a generic software overwrite makes every SSD/NVMe device NZISM-sanitized.

Solid-state storage can use:

• Flash Translation Layers
• Wear Leveling
• Garbage Collection
• Spare NAND Blocks
• Over-Provisioning
• Remapping
• Controller-Managed Physical Locations

A host-level overwrite may therefore address logical storage without necessarily overwriting every historical physical flash location.

The NZISM specifically recognizes the difficulty of effectively sanitizing flash and solid-state storage.

This makes the NZISM approach particularly relevant to modern data-erasure workflows because it does not assume that the same overwrite technique is suitable for every storage technology.

Hybrid storage devices can combine magnetic and solid-state components.

The applicable NZISM controls must therefore be considered according to the actual storage architecture.

DSP can identify the storage type and allow the operator to determine the appropriate sanitization or destruction workflow.

The key principle is:

NZISM addresses not only individual storage media but also IT equipment containing storage media.

This is important for:

• Desktop Computers
• Laptops
• Servers
• Storage Appliances
• Enterprise Systems
• Network Equipment
• Other IT Equipment Containing Information-Bearing Media

The NZISM framework requires agencies to address sanitization or destruction before equipment is declassified and released for disposal.

DSP can support the device-level sanitization component of this process.

Sanitization and declassification are related but should not be treated as identical.

NZISM requires agencies to declassify media and IT equipment before disposal into the public domain. Media that cannot be effectively sanitized or declassified must be destroyed rather than released.

1. 01Identify Asset
2. 02Determine Classification
3. 03Sanitize Or Destroy
4. 04Verify
5. 05Declassification / Approval
6. 06Release / Disposal

This provides a broader lifecycle context around data erasure.

NZISM is particularly relevant to secure IT asset retirement because the NCSC's current asset-lifecycle guidance states that organizations should ensure data is removed before devices are sold, disposed of or reused. It also recommends sanitizing devices before internal reuse.

DSP can support an ITAD workflow such as:

1. 01Asset Intake
2. 02Device Identification
3. 03Storage Assessment
4. 04NZISM Sanitization
5. 05Read-Back Verification
6. 06Validation
7. 07Certificate
8. 08Reuse / Redeploy / Destroy

This provides a documented connection between the physical asset and its sanitization result.

For supported magnetic HDDs, DSP can capture device information before and during sanitization.

Bad sectors can directly affect whether a storage device can be successfully sanitized.

DSP can detect and document:

• Existing Bad Sectors
• Read Failures
• Write Failures
• Unstable Sectors
• Inaccessible Regions
• Sanitization Exceptions

Where the selected sanitization operation cannot successfully address required storage locations, the device can be flagged for the applicable destruction workflow rather than incorrectly marked as successfully sanitized.

This is consistent with the NZISM principle that unsuccessful sanitization requires destruction.

A factory reset should not be presented as equivalent to secure media sanitization.

The current NZISM explicitly states that “factory reset” or similar terminology does not constitutesanitizationof media.

Therefore:

Factory Reset≠NZISM Media Sanitization

A proper sanitization workflow requires an appropriate sanitization operation and verification.

DSP can document the sanitization operation and its read-back verification.

However, NZISM's historical/current guidance has also recognized the value of independent verification: earlier NZISM versions stated that agencies should verify sanitized media using a different product from the one that performed the initial sanitization.

For organizations requiring this additional assurance, an independent verification process can therefore be incorporated into the organization's sanitization policy.

1. 01DSP Sanitization
2. 02DSP Verification
3. 03Independent Verification, Where Required
4. 04Validation
5. 05Final Record

This should be represented as an organizational assurance process, not as a claim that every DSP operation automatically constitutes independent NZISM verification.

Where sanitization is not technically feasible, NZISM provides a destruction path.

The current manual identifies media types that must be destroyed where they cannot be effectively sanitized and includes requirements around destruction equipment and approved destruction facilities.

DSP therefore works best as part of a complete workflow:

This is especially important for:

• SSDs
• Flash Media
• Faulty Storage
• Unrecoverable/inaccessible Media
• Media Subject To Higher Security Requirements

They are therefore not competing wiping algorithms.

NZISM is a broader New Zealand Government security framework containing specific media-management and sanitization controls.

IEEE 2883-2022 focuses on storage sanitization methods and technology-specific requirements.

NZISM provides the broader New Zealand Government information-security context and specifies controls for sanitization, destruction and disposal.

A practical workflow can therefore be:

1. 01NZISM Security Requirement
2. 02Storage Technology Assessment
3. 03Applicable Technical Sanitization Method
4. 04Execution
5. 05Verification
6. 06NZISM Documentation / Assurance

DSP can provide the operational sanitization component within this type of workflow.

NZISM is particularly relevant to:

• New Zealand Government Agencies
• Crown Entities
• Government Contractors
• Government IT Suppliers
• Secure ITAD Providers
• Data Centers
• Enterprise Environments
• Organizations Handling Classified Information

The NCSC states that NZISM is specifically intended for New Zealand Government agencies while also encouraging Crown entities, local government and private-sector organizations to use it.

DSP can support offline sanitization workflows where internet connectivity is restricted or unavailable.

This can be useful for:

• Government Environments
• Air-Gapped Networks
• Secure Facilities
• Restricted Laboratories
• Controlled ITAD Environments
• Sensitive Enterprise Systems

The sanitization operation can be executed locally while maintaining device and verification information for reporting.

DSP can generate an audit-ready sanitization certificate documenting the operation performed by DSP.

NZISM's sanitization requirements are particularly relevant when media is:

• Reused
• Redeployed
• Transferred
• Reclassified
• Disposed
• Released From An Organization

The NCSC's current asset-lifecycle guidance also recommends sanitizing devices before reuse or repurposing.

DSP can provide the operational evidence required to show what sanitization method was executed and what verification result was obtained.

NZISM is one of the government-oriented sanitization frameworks supported through DSP.

The DSP Sanitization Engine can provide separate selectable profiles for modern and historical methodologies such as:

Each methodology remains a separate selectable DSP sanitization profile, with its applicable execution, verification and reporting workflow.

• 01DSP-DPDP India
• 02NIST SP 800-88 Rev. 1 Clear
• 03NIST SP 800-88 Rev. 1 Purge
• 04NIST SP 800-88 Rev. 2 Clear
• 05NIST SP 800-88 Rev. 2 Purge
• 06IEEE 2883-2022
• 07ISO/IEC 27040:2024
• 08Random Overwrite
• 09DoD 5220.22-M
• 10DoD 5220.22-M ECE
• 11NSA/CSS Policy Manual 9-12
• 12HMG IS5 Baseline
• 13HMG IS5 Enhanced
• 14CSEC ITSG-06
• 15BSI-GSE
• 16BSI VSITR
• 17Gutmann Method
• 18Schneier Algorithm
• 19Pfitzner Method
• 20AFSSI-5020
• 21AR 380-19
• 22GOST R 50739-95
• 23NZISM
• 24NAVSO P-5239-26
• 25RCMP TSSIT OPS-II