In today’s fast-paced world, people and companies store large amounts of data, often confidential, on laptops, servers, hard drives, memory cards and other storage media. So, whether you are upgrading your machine, repurposing systems, or disposing of old drives, it is important to make sure that sensitive data cannot be accessed or recovered by others. For this, you will need an efficient and secure data sanitization method, that is, cryptographic erase.
This technology has been widely adopted since it presents a faster, more efficient, and economical way of making stored data unreadable. Unlike conventional erasure, which overwrites data sectors, cryptographic erase makes data unreadable by deleting the keys that decrypt it.
In this guide, we will cover what cryptographic erase is, how it works, its advantages, how to implement it and how it compares with secure erase.
What Is Cryptographic Erase?
The technique saves a lot of time compared with traditional ways to wipe drives.
How Does Cryptographic Erase Work?
Step 1: Data Encryption
During writing of the data into the storage media, automatic encryption takes place using a data encryption key (DEK). The encryption process happens within the storage media itself.
Step 2: Key Management
Encryption keys are held in the drive controller of a self-encrypting drive, or in an external key manager such as a hardware security module (HSM) or a cloud key management service. It is impossible to decrypt the data without knowing the key.
Step 3: Erasure Procedure Initiation
When storage media reaches end of life or is reused, an administrator can start the erasure.
Step 4: Key Destruction
The key that enables decryption of the data is deleted. It is the most important step in cryptographic erasing since the key is the means of decrypting the data.
Step 5: Verification
Verification checks on most enterprise-grade solutions ensure successful key deletion. After successful verification, the encrypted data can no longer be accessed.
Because only the key is deleted and not every data block on the drive, the operation can be performed in mere seconds to minutes, irrespective of the size of the drive.
Advantages of Cryptographic Erasure
Cryptographic erasure is becoming more popular due to the various benefits it offers.
- Fast Data Sanitization
Overwriting takes time, especially on large storage drives. Since cryptographic erasure simply deletes encryption keys, sanitizing terabytes of data is possible in no time.
- More Secure
Deleting the keys makes the data practically impossible to recover if no copy of the key exists. Even powerful forensic recovery programs cannot recover data without the key.
- Reduced Hardware Wear
Overwriting multiple times may result in deterioration of SSDs or flash drives. The use of key deletion avoids unnecessary write cycles and increases hardware longevity.
- Economical Process
As the process does not take much time or effort, it is a very economical approach for corporations dealing with substantial storage capacities.
- Compliance
Many regulations mandate that organizations dispose of their data securely. Cryptographic sanitization is a recognized method in NIST SP 800-88 and may assist corporations in meeting data protection rules such as the GDPR.
Reference: NIST SP 800-88 Rev. 2: Guidelines for Media Sanitization
Methods of Implementation for Cryptographic Erase
Depending on the environment, there are different ways to implement cryptographic sanitization of data.
#1: Self-Encrypting Drives (SEDs)
Self-Encrypting Drives automatically encrypt all data written on the drive through hardware-based encryption.
Process:
- Data encryption occurs during writing to the drive.
- Encryption keys are saved inside the drive.
- An erase instruction leads to deletion of encryption keys.
- Sanitization of the drive is automatic.
Advantages:
- Very quick sanitization process.
- Little consumption of system resources.
- Excellent security controls.
#2: Software Encryption Systems
This method uses software-based encryption, for example BitLocker.
Approach:
- Data is encrypted with keys generated by software.
- Keys are kept in secure vaults.
- Keys are destroyed by administrators for sanitization purposes.
- Encrypted data is rendered unintelligible.
Pros:
- Simple integration with existing systems.
- Suitable for endpoints and servers.
- Can be centrally managed.
Note: BitLocker recovery keys can also be saved in a Microsoft account, Microsoft Entra ID, Active Directory or on a printout. Delete every copy of the key, or the data can still be unlocked.
#3: Enterprise Storage Arrays
Enterprise storage arrays use encryption and key management features.
Process:
- Data is encrypted across all storage systems.
- The encryption keys are centrally stored.
- Key deletion is performed through management consoles.
- Storage devices can be easily re-tasked.
Benefits:
- Scalability in a larger deployment scenario.
- Central management.
- Ensures compliance.
#4: Cloud-Based Environment
Encryption is commonly used by cloud vendors to secure their client data.
Process:
- The data is encrypted prior to storage.
- Cloud key management services control the encryption keys.
- The keys are deleted when the data needs sanitizing.
- The encrypted data becomes unreadable.
Benefits:
- Ideal for virtual environments.
- Can be used for large cloud infrastructures.
- Makes secure data deletion easier.
Cryptographic Erase vs. Secure Erase
One of the most common comparisons in data sanitization is that of cryptographic erase vs. secure erase.
| Feature | Cryptographic Erase | Secure Erase |
| Method | Deletes encryption keys | Overwrites storage blocks |
| Speed | Very fast | Slower for large drives |
| SSD Wear | Minimal | Can increase wear |
| Requirement | Encrypted storage | Works on encrypted and non-encrypted drives |
| Data Recovery | Practically impossible without key | Practically impossible to recover after overwriting |
| Scalability | Highly scalable | Time-consuming for large environments |
In the comparison between cryptographic erasure and secure erasure, what needs to be considered is the presence of encryption. For the former, encryption allows the quick erasure of data through the destruction of keys.
On the other hand, secure erasure is still an acceptable technique for non-encrypted storage devices.
Alternative Solution for Secure Data Wiping
Best Practices to Follow While Conducting Cryptographic Erase
Follow these best practices when you run a cryptographic erasure:
- Ensure that encryption is enabled from the beginning.
- Use approved algorithms for encryption.
- Adopt a key management system.
- Confirm the success of key destruction process.
- Keep track of all log files.
- Review your data disposal policy regularly.
What Are the Limitations of Cryptographic Erase?
Despite the high effectiveness and safety associated with cryptographic erase, there are certain issues related to this sanitization approach. Businesses should take them into account when deciding whether to use cryptographic erase as the main approach to destroying data.
- It Needs Prior Encryption
The main drawback of cryptographic erase is that it only works on encrypted data. Without proper data encryption, even deletion of encryption keys will not make the data unavailable.
Impact: If data is not encrypted, it might still be available on the storage medium after performing cryptographic erase.
- It Is Vulnerable to Key Management Issues
As cryptographic erase is completely dependent on encryption keys, proper management of these keys becomes very important.
Impact: Poor key management might lead to failure of the entire data sanitization procedure.
- Not Supported by All Storage Devices
Some of the older hard drives, storage systems, and consumer-level devices lack the capability to enable SED technology and the feature of cryptographic erase.
Impact: Other forms of disk sanitization such as secure erase or data overwriting may have to be employed.
- Verification May Prove Difficult
Overwriting changes data at the sector level. Cryptographic erasure removes the keys instead, so the change is not visible on the disk. In some cases, verification of the elimination process can pose difficulties.
Impact: Audits and other forms of validation will be required for compliance purposes.
- Unsuitable for Damaged Devices
When the storage drive is damaged or has hardware issues or cannot be accessed due to corruption, cryptographic erasure may prove impossible.
Impact: Physical destruction may have to be performed.
- Risk of Key Recovery
If the encryption keys have been stored in backups, backup tools, key escrow or other storage, it is possible to decrypt the data after erasure.
Impact: The failure to eliminate keys leads to vulnerabilities.
- Residual Metadata Can Be Available
There are cases where some system metadata, logs, or configuration settings may be found outside the scope of the encrypted data.
Impact: Even though the data itself is not available anymore, some traces can reveal what happened before.
Final Takeaway
Cryptographic erase has proved to be one of the most effective ways of wiping out the information from storage media that have been encrypted with the help of encryption keys. By eliminating the encryption keys instead of erasing the data on the whole drive, companies can make their information unusable quickly.
As storage grows, the conventional overwriting method is becoming less practical because of the time it needs. Cryptographic erase is especially useful for companies, in the cloud and on self-encrypting drives. Understanding the difference between cryptographic erase and secure erase becomes quite useful too.
By understanding both concepts effectively, you can make an informed decision about which process is best for you.