In-Depth

Sharing Hardware Cryptography No Longer Enough

It's no longer enough just to use encryption. Now what's important is how well you've used encryption, how well you administer it, and how well you can prove to auditors what you're doing.

• By Mathew Schwartz
• 10/22/2003

New technologies are giving security managers hardware cryptography at a lower price point. The “hardware” part of the mix is crucial, especially in large environments that must quickly and reliably encrypt and decrypt massive amounts of data. While “64-bit computers are designed to handle data, they're not architecturally designed to handle 1000 bit keys or 2000 bit keys,” notes Richard Moulds, vice president of marketing for cryptography provider nCipher.

Ever watch a server try? It can slow the machine to a 50th (or less) of normal speed. “Performance is a major issue when you start deploying cryptography, particularly if you start to deploy asymmetric cryptography—SSL, or public key cryptography where you’re signing documents.”

Historically, companies tapped outside hardware—security modules—to handle encryption and circumvent any slowdown. “These things have quite a long history,” Moulds notes. “Way back in the days of mainframes, there were host security modules connected to mainframes.” Then, however, “in the e-commerce rush, hardware cryptography wasn’t available.” That is to say, companies’ desire to invent and get e-commerce systems online rapidly outpaced hardware cryptography companies’ ability to secure them. They needed time to catch up, and did, in what’s now known as hardware security modules (HSM), “peripheral devices … that sit inside servers, that allow the hardware platform to overcome their deficiencies in cryptography.”

Without hardware encryption, whenever a server terminates an SSL session or signs a certificate, the keys used are in the memory space, leaving the machine susceptible to a key-finding attack. As it turns out, discerning a key from the other information floating around the memory is relatively easy, providing an attacker gets access to the memory (think insider attack).

The problem is that if a key is compromised, it can unlock historical secrets. “If [an attacker] can find the key, they can pretty well replay any SSL session that’s occurred since the digital certificate was issued, which [typically] is about two years; SSL keys don't change very often,” Mould cautions.

This goes beyond e-commerce, too. “SSL is not just about browsers over the Internet; a lot of companies are using it to hook up their internal servers. That means you have authentication, internal keys, and those keys can be abused if you're not careful.”

Typically, each server gets its own HSM, an expensive proposition that relegated them to ultra-security conscious industries such as government and financial services. The paradigm, however, has recently gone a step further with HSMs that can be shared. For example, nCipher released netHSM, “a secure cryptographic module that is compatible with existing nCipher HSMs and that can be shared by multiple servers,” says Graham Titterington, principal analyst and security expert with Ovum. In short, it’s a network-attached hardware security module that can be shared by multiple servers or applications that need to perform any cryptographic-related functions—SSL, user authentication, remote access to digital rights management, or Web services.

Introducing a modular—as opposed to dedicated—approach, says Titterington, “opens up new opportunities to deploy hardware security in areas that organizations would previously have found difficult to justify."

“If you were going to buy four or five HSMs, then it's probably cheaper to buy a shared HSM,” says Mould.

One impetus for using hardware-based encryption could come from regulations such as the Health Insurance Portability and Accountability Act. “A lot of these newer standards are saying, think about encryption—it's not good enough to use encryption, it's how well you've done it, how well you administer it, and how well you can prove to auditors what you're doing,” says Mould.

“The hygiene around how companies manage keys is becoming one of the major issues for administering servers.”