Why Data Erasure Matters: A Beginner’s Guide (Deletion vs. Erasure)

When you sell, return, or dispose of a smartphone or PC, the biggest risk is simple:
data that looks “deleted” can sometimes be recovered.
This article explains the difference between deletion and erasure, common leak scenarios, and a practical checklist.

What is data erasure?

Data erasure is a technical process that makes stored data unrecoverable in practice.
It is not the same as removing files from view.

Deletion vs. erasure

Regular deletion / reset

• Often removes references to data, while the underlying data may remain
• Recovery can be possible depending on the media and methods used

Data erasure

• Uses overwriting or media-appropriate methods to reduce recoverability
• Can produce records (logs/certificates) for governance and audits

What can go wrong (information leak impact)

• Individuals: photos, contacts, messages, social and financial account exposure
• Enterprises: customer data, contracts, trade secrets, partner trust and audit issues

Common scenarios where erasure is required

• Device resale / trade-in
• Lease returns and vendor returns
• Server refresh and storage replacement
• Employee offboarding and device collection
• Office closure and disposal

A practical erasure checklist

1. Backup: copy data you need to keep
2. Unlink accounts: cloud services, MDM, device bindings
3. Confirm encryption: check device encryption state
4. Run erasure: choose a method suitable for HDD/SSD/mobile devices
5. Verify & record: confirm outcomes; keep logs/certificates if required

FAQ

Q. Is factory reset enough?

In many cases, reset alone does not guarantee unrecoverability.
The right approach depends on your device type and operational context (encryption, backups, MDM, etc.).

Q. Is overwriting always safe for SSDs?

SSD behavior differs from HDDs, and overwriting may not affect all physical areas as intended.
Consider media-specific approaches where appropriate.

Next steps

If you operate at scale or need certificates for partners/audits, process design matters.
Share your requirements via Contact. For pricing, see Pricing.

GDPR & Japan’s Personal Data Protection Law: Practical Data Erasure Obligations for Enterprises

For organizations handling personal data, data erasure is not a “cleanup task.”
It sits at the intersection of regulatory compliance, internal governance, and partner requirements.
This article summarizes practical points for designing an erasure process that you can execute and explain.

Disclaimer: This article is general information and not legal advice. Please consult official sources and professionals for final decisions.

Key takeaways

• How to think about retention, minimization, and deletion requests under GDPR
• What to focus on in Japan’s Personal Information Protection Act: security controls and vendor oversight
• Why evidence (logs/certificates) matters for audits and accountability

Erasure = compliance + accountability

In practice, “we erased it” is not enough. You often need to demonstrate:
what was erased, when, by whom, by which method, and with what result.

GDPR: what to pay attention to

• Storage limitation: avoid retaining data longer than necessary for its purpose
• Data minimization: collect/retain only what you need
• Deletion requests: establish a workflow and keep records of actions taken

GDPR includes enforcement mechanisms, and risk cannot be ignored.
Enforcement outcomes depend on context and specifics, so use official sources and professional review when designing policies.

Japan’s Personal Information Protection Act: what to pay attention to

• Security management measures: organizational, human, physical, and technical controls
• Vendor oversight: governance over processors, subcontractors, and operational controls
• After purpose fulfillment: do not keep unnecessary data—operate deletion/disposal routines

Practical checklist for enterprises

1) Create an erasure policy

• Retention periods by data type (rationale, owner, exceptions)
• Workflows for disposal/return/transfer
• Partner requirements (proof, witness, chain-of-custody)

2) Choose methods that match the media

• Logical erasure: overwriting, where appropriate for the media and threat model
• Cryptographic erasure: key destruction, assuming encryption is correctly implemented
• Physical destruction: for final disposal when reuse is not required

3) Keep evidence (logs / certificates)

• Device identifiers linked to your asset ledger
• Method, timestamp, operator, and result (success/failure)
• Erasure certificates (e.g., PDF) when required

How MASAMUNE helps (general)

Beyond choosing an erasure method, you need a process that reliably runs at scale.
MASAMUNE supports operations with execution records and audit-friendly evidence management.

• Searchable execution logs
• Certificate issuance/storage for audit trails
• Process design aligned with return/transfer/disposal workflows

Summary

Data erasure is a core governance process. The most effective practical approach is building a system where you can
explain “what, when, how, by whom, and with what outcome.”

Next steps

If you want to design an erasure process aligned with your devices, workflows, and evidence requirements,
contact us via Contact. For pricing, see Pricing.

NIST SP 800-88 Explained: Clear / Purge / Destroy (Media Sanitization)

One of the most common causes of post-disposal incidents is simple: data that was “deleted” can still be recovered.
A widely referenced guideline for preventing this is NIST SP 800-88, published by NIST (the U.S. National Institute of Standards and Technology).

What you’ll learn (Key takeaways)

• What “media sanitization” means in NIST SP 800-88
• The 3 levels: Clear, Purge, Destroy — and how they differ
• How to choose the right level for reuse, transfer, or disposal
• What evidence/logging you should keep for audits and compliance

What is NIST SP 800-88?

NIST SP 800-88 is a guideline for sanitizing storage media (HDD/SSD/mobile devices/removable media, etc.)
in a way that matches your threat model and device characteristics.
The key point is that “factory reset” or “file deletion” is not the same as being unrecoverable.

The three sanitization levels

1) Clear

A logical approach intended to reduce the likelihood of recovery using typical software tools.
Examples include full-area overwriting and using OS-provided secure erase functions where appropriate.

• Best for: Internal reuse, low-to-medium sensitivity data
• Note: The correct method depends on the media type (especially SSDs)

2) Purge

A stronger level intended to address more capable adversaries and media-specific behavior.
For SSDs, this may include device-specific commands (e.g., Secure Erase) or cryptographic erasure.

• Best for: External transfer/sale, data containing personal or sensitive information
• Note: Choosing the wrong approach can create a “false sense of erasure”

3) Destroy

Physical destruction where the media is not intended to be reused.
This is considered when the goal is to practically eliminate recovery by destroying the storage medium.

• Best for: Final disposal, extremely high sensitivity scenarios
• Note: Operational controls (chain-of-custody, witness, records) matter as much as the act itself

How to choose the right level

• Data type: personal data, customer records, contracts, trade secrets
• Disposition: reuse internally vs. transfer outside vs. disposal
• Media: HDD/SSD/mobile/tablet/external/server
• Evidence requirements: do you need proof for audits or partners?

Audit-ready evidence: what to record

For audits and incident response, the most important question is: “What happened, to which device, how, and with what result?”
Having consistent records makes compliance and partner communication much easier.

• Execution logs (device identifier, method, result, errors)
• Operator/location tracking and asset ledger linkage
• Erasure certificates when required (e.g., PDF)

FAQ

Q. Isn’t factory reset / deletion enough?

In general, deletion or reset does not guarantee unrecoverability.
The proper method depends on the threat model and the type of media.

Q. Is overwriting always safe for SSDs?

SSD behavior differs from HDDs due to wear leveling and internal mapping.
Media-specific approaches such as Secure Erase or cryptographic erasure should be considered.

Next steps

If you need help designing an erasure process that matches your devices, workflow, and evidence requirements,
start by listing your media types, volumes, return/disposal flow, and proof needs.
See Pricing and Contact for next actions.