NIST SP 800-88 4: Cryptographic Erase, Key Management, and Verification of Erase

Implement Cryptographic Erase (CE) per NIST SP 800-88 Rev 1 Section 2.5.2 + Appendix A as a Purge method where applicable. CE prerequisites per Section 2.5.2: (a) data has been encrypted from the moment of first write to the storage + or all data has been read and re-written through the encryption layer, (b) the encryption implementation is sufficiently strong (AES-128 or AES-256 with proper mode + key strength + key management), (c) all instances of the data encryption key are destroyed including backups + key escrow + recovery copies + hardware security module copies, (d) sanitization of the data encryption key is verified. Key management for CE must include (a) key inventory mapping keys to data and media + (b) controlled key generation + storage + use + (c) tamper-evident key destruction procedures per FIPS 140 validated cryptographic module where possible + (d) audit trail of key destruction events linked to the data + media sanitized. Verification of sanitization per Chapter 4 Section 4.7 requires (a) representative sampling for Clear and Purge with documented sampling methodology, (b) full verification where feasible, (c) destruction verification via visual inspection + chain-of-custody documentation + third-party witness where applicable.