Re: fyi: bear/enforcer open-source TCPA project
You propose to put a key into a physical device and give it to the public, and expect that they will never recover the key from it? Seems unwise. You think the public can crack FIPS devices? This is mass-market, not govt-level attackers. Second, if the key's in hardware you *know* it's been stolen. You don't know that for software. /r$ -- Rich Salz Chief Security Architect DataPower Technology http://www.datapower.com XS40 XML Security Gateway http://www.datapower.com/products/xs40.html XML Security Overview http://www.datapower.com/xmldev/xmlsecurity.html - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: fyi: bear/enforcer open-source TCPA project
Rich Salz [EMAIL PROTECTED] writes: Second, if the key's in hardware you *know* it's been stolen. You don't know that for software. Only for some definitions of stolen. A key held in a smart card that does absolutely everything the untrusted PC it's connected to tells it to is only marginally more secure than a key held in software on said PC, even though you can only steal one of the two without physical access. To put it another way, a lot of the time you don't need to actually steal a key to cause damage - it doesn't matter whether a fraudulent withdrawal is signed on my PC with a stolen key or on your PC with a smart card controlled by a trojan horse, all that matters is that the transaction is signed somewhere. Peter. - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
RE: fyi: bear/enforcer open-source TCPA project
There are roughly 1B GSM/3GPP/3GPP2 SIMs in daily use and the number of keys extracted from them is diminishingly small. -Original Message- From: bear [mailto:[EMAIL PROTECTED] Sent: Thursday, September 11, 2003 3:43 AM To: Sean Smith Cc: [EMAIL PROTECTED] Subject: Re: fyi: bear/enforcer open-source TCPA project On Wed, 10 Sep 2003, Sean Smith wrote: So this doesn't work unless you put a speed limit on CPU's, and that's ridiculous. Go read about the 4758. CPU speed won't help unless you can crack 2048-bit RSA, or figure out a way around the physical security, or find a flaw in the application. You propose to put a key into a physical device and give it to the public, and expect that they will never recover the key from it? Seems unwise. Bear - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED] - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: fyi: bear/enforcer open-source TCPA project
Thus spake Rich Salz ([EMAIL PROTECTED]) [11/09/03 08:51]: You propose to put a key into a physical device and give it to the public, and expect that they will never recover the key from it? Seems unwise. You think the public can crack FIPS devices? This is mass-market, not govt-level attackers. And 'the public' doesn't include people like government level attackers? People like cryptography experts? People who like to play with things like this? 'The public' only includes the sheeple, and nobody else? - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
is secure hardware worth it? (Was: Re: fyi: bear/enforcer open-source TCPA project)
Just to clarify... I'm NOT saying that any particular piece of secure hardware can never be broken. Steve Weingart (the hw security guy for the 4758) used to insist that there was no such thing as tamper-proof. On the HW level, all you can do is talk about what defenses you tried, what attacks you anticipated, and what tests you tried. What I am saying is that using secure coprocessors---defined loosely, to encompass this entire family of tokens---can be a useful tool. Whether one should use this tool in any given context depends on the context. Are there better alternatives that don't require the assumption of physical security? How much flexibility and efficiency do you sacrifice if you go with one of these alternatives? How dedicated is the adversary? What happens if a few boxes get opened? How much money do you want pay for a device? Some cases in point: it's not too hard to find folks who've chosen a fairly weak point on the physical security/cost tradeoff, but still somehow manage to make a profit. Of course his all still leaves unaddressed the fun research questions of how to build effective coprocessors, and how to design and build applications that successfully exploit this security foundation. (Which is some of what I've been looking into the last few years.) --Sean -- Sean W. Smith, Ph.D. [EMAIL PROTECTED] http://www.cs.dartmouth.edu/~sws/ (has ssl link to pgp key) Department of Computer Science, Dartmouth College, Hanover NH USA - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: fyi: bear/enforcer open-source TCPA project
How can you verify that a remote computer is the real thing, doing the right thing? You cannot. Using a high-end secure coprocessor (such as the 4758, but not with a flawed application) will raise the threshold for the adversary significantly. No, there are no absolutes. But there are things you can do. The correct security approach is to never give a remote machine any data that you don't want an untrusted machine to have. So you never buy anything online, or use a medical facility that uses computers? -- Sean W. Smith, Ph.D. [EMAIL PROTECTED] http://www.cs.dartmouth.edu/~sws/ (has ssl link to pgp key) Department of Computer Science, Dartmouth College, Hanover NH USA - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
