Data Center Encryption Is Key To Security

Why bring encryption into the glass house? To paraphrase bank robber Willie Sutton, because that's where the data is.

To date, most data center security efforts have been focused on protecting against Internet threats. However, IT can no longer ignore physical security: Thieves recently broke into the Chicago data center of managed Web hosting provider C I Host and stole server hardware--for the fourth time. Meanwhile, backup tapes are frequent targets for theft because they're often out of IT's direct possession. The Privacy Rights Clearinghouse Web site documents more than 40 cases of tape theft since 2005, and it's likely that far more were never reported. In our 2008 Strategic Security Survey, the theft of computers or storage systems was among the top five breaches seen as most likely to occur in the coming year.

Clearly, encrypting hard drives and tapes is vital to protect data. So why aren't organizations rushing to sign on? The complexity of managing keys is a top deterrent to ubiquitous encryption. After all, there are many ways to encrypt, but key management is where all these projects succeed or fail. And failure is most likely to occur several years out, after the hole has been dug quite deep. Some information must be kept for decades, after all, and storing the keys needed to access that data securely for 10 or 20 years is a challenge.

Fortunately, advances in managing keys as well as new options for encrypting data at each step within the backup process make it much less likely lost keys will come back to haunt you. Most of the vendors we spoke with understand the problem and are working to solve it. RSA's Key Management Suite, for example, works with encryption products from RSA partners to give IT a single management point for all encryption keys.

Encryption vendors also have started to build key management into their products or offer these capabilities as options for companies with modest requirements.

TALES OF THE TAPES
Security analysts love the idea of encrypting all data on the host before it's even sent to a backup server. This guarantees end-to-end privacy and minimizes the number of places where mistakes can be made. And plenty of products provide this capability. Symantec's NetBackup is a good example--just generate a key and click a box within the user interface to enable encryption of any data set. The backup server instructs the client to encrypt on the fly.

This approach has downsides, however. By encrypting data at the host, deduplication has to happen at the server. And encryption adds load to the server, lengthening the backup window and perhaps affecting performance. Moreover, encrypted data is supposed to be indistinguishable from random data, so it tends to render tape-drive compression completely ineffective. Since most tape drives claim a hardware compression rate of at least 2-to-1, server-side encryption can easily double your tape consumption.

But key management may well be the worst problem. Backup vendors are only now starting to add key management capabilities to their software; most still rely on the backup admin to handle management tasks. You'd think someone would take this off our hands.

AUTOMATION, ANYONE?
Moving encryption closer to tape drives are appliances that encrypt data as it heads to the tape library. These devices can be inserted into the Fibre Channel fabric of the SAN, the SCSI connections to the tape drives, or iSCSI networks, providing a tremendous amount of flexibility. Appliances take the processing load off servers and are popular choices in environments with a variety of backup software and hardware, or when speed of installation and ease of setup are priorities. NetApp's Decru division and nCipher's NeoScale CryptoStor Tape even perform compression on the box, and a separate key management appliance or software system provides the key archiving and security needed to trust the system over many years.

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As good as this sounds, do your due diligence before investing in an encryption appliance. Cisco released its Storage Media Encryption blade for its director-class Fibre Channel switches amid turmoil in the field. Customers of one vendor, Kasten Chase, were left holding encrypted tapes with no upgrade cycle or support. Similar woes faced some customers of NeoScale when nCipher bought its tape encryption business but left out the company's disk encryption customers.

Perhaps the most exciting innovation for tape encryption has been the addition of encryption capabilities to the drives themselves. Sun's StorageTek 10000B and LTO4 Ultrium drives from IBM, HP, and Quantum have encryption hardware built in. This adds minimal cost and should have very little impact on performance. Compression can be performed just before encryption, minimizing storage space, and most importantly, encrypted data can be read just after it's written, decrypted, and compared with the original to ensure that there are no errors.

IBM's tape encryption works with RSA's Key Management Suite, and IBM also ships its own simplified Enterprise Key Manager (EKM), which supports a novel twist useful to companies that must ship data to partners. IBM EKM uses public key cryptography to encrypt data on the tape to the partner's public key. The partner can then use its private key to read the data. In this way, no secret key exchange has to happen between the partners, but the tapes remain secure.

(click image for larger view) DON'T FORGET YOUR DISKS
Encrypting disk arrays and SAN storage seems at first like an unnecessary step. Aside from a few spectacular cases, theft of servers from data centers is still rare. What happens to disks as they are retired from the data center is a more frequent concern. Ideally, companies should have a strong program in place to ensure that disks are wiped or destroyed as they leave the premises. But this process is subject to human failings and relies on cooperation with vendors when drives under maintenance need to be replaced.

Ubiquitous disk encryption can delete these concerns.

As with tapes, there are choices and trade-offs in disk storage encryption. While not strictly limited to the data center, PGP's NetShare is an elegant option for companies that can easily wrap their arms around users with sensitive data--for instance, a research group or credit department. These users' computers can be equipped with NetShare, and any time content is written to an encrypted folder or by a specified application, the files are encrypted with the public keys of the authorized users.

This sounds similar to Microsoft's Encrypting File System, but it takes the concept further. Rather than only remaining encrypted while on the intended file system, NetShare-encrypted files can be copied to other folders, servers, or even portable media, and still retain their encryption. This is especially helpful for companies with a diverse server environment or where files are frequently transferred.

Another option is exemplified by SAN company EMC's PowerPath storage management software, which runs on servers and provides full access to the virtualization and redundancy capabilities of EMC's storage systems. By adding data encryption to PowerPath, EMC enables all SAN clients to encrypt data at the server level; encryption is limited to Windows, Solaris, and Linux, although other platform support is expected.

EMC's approach lets storage admins decide which virtual volumes to encrypt and, of course, it's integrated with its RSA division's Key Management Suite. Because encryption is incorporated directly into the storage management software, this method avoids conflicts with storage optimization techniques within the SAN.

Seagate recently introduced enterprise-grade disk drives with hardware encryption. By populating an array with these drives, a storage vendor can offer media encryption with no additional overhead. Key management is still an issue, but vendors such as IBM are integrating these devices into their key management software.

This approach requires the least changes to a company's server or storage architecture, because it occurs after all other storage optimization, such as RAID, virtualization, compression, and deduplication.

Finally, encrypting Ethernet link-layer traffic may seem like overkill, but that's exactly what the IEEE 802.1AE specification does (see story, p. 46). Cisco's TrustSec initiative uses 802.1AE as the basis for a sophisticated role-based access control system in which the network can tag data packets with user identity information that it can use to make access control decisions.