Canadian CSEC ITSG-06 erase method

Overview

Full name: ITSG-06 — Clearing and Declassifying Electronic Data Storage Devices

Issued by: Communications Security Establishment Canada (CSEC)

Purpose: To ensure that sensitive or classified data is irrecoverable from storage media before reuse, downgrade, or disposal.

Technical Description

The ITSG-06 erase method provides detailed procedures for clearing and purging magnetic media (e.g., hard drives, tapes) and solid-state storage (e.g., SSDs, flash drives).

While implementations can vary slightly based on media type and classification level, the general overwrite method for magnetic media is as follows:

Magnetic Storage (HDDs, tapes):

• First pass: Overwrite all addressable storage locations with a fixed pattern (e.g., binary 0s).
• Verification: Verify that the last overwrite pass was successful (bit-level verification on a sample or full-drive basis).
• Third pass: Overwrite all addressable storage locations with random data.
• Second pass: Overwrite all addressable storage locations with the complementary pattern (e.g., binary 1s).

This is effectively similar to the DoD 5220.22-M (3-pass) method, with CSEC validation requirements.

Solid-State Storage (SSDs, Flash, Hybrid Drives):

• ITSG-06 discourages overwriting due to wear-leveling and remapping mechanisms in SSDs.

• Instead, it recommends:

  • Using built-in ATA Secure Erase or cryptographic erase functions.

  • Physical destruction (e.g., shredding, degaussing, or incineration) if the device handled highly classified data.

Rationale and Effectiveness

The ITSG-06 standard is based on the principle that residual data (remanence) on magnetic domains or flash cells can potentially be recovered with advanced forensic techniques.

Multiple overwriting passes or hardware-supported secure erase ensures that no readable magnetic signature of the original data remains.

Use Cases

• Canadian federal departments and agencies:

  To securely sanitize storage media containing Protected or Classified information before re-use or release.

• Defense contractors and critical infrastructure operators:

  When handling Canadian government or NATO-classified data that falls under CSEC oversight.

• Private sector and IT asset disposal firms:

  Implementing ITSG-06 erasure processes to comply with Canadian privacy laws and data protection standards (e.g., PIPEDA).

• Cross-border compliance:

  Companies operating in both the U.S. and Canada may adopt ITSG-06 alongside DoD 5220.22-M or NIST 800-88 for harmonized data sanitization.

Modern Considerations

• Like DoD 5220.22-M, ITSG-06 is being phased out in favor of newer approaches aligned with NIST SP 800-88 Rev.1 and CSE’s updated guidance for data destruction.

• For SSDs and encrypted media, CSEC recommends cryptographic erase or physical destruction as the most reliable methods.

Summary