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]
fyi: bear/enforcer open-source TCPA project
The Bear/Enforcer Project Dartmouth College http://enforcer.sourceforge.net http://www.cs.dartmouth.edu/~sws/abstracts/msmw03.shtml How can you verify that a remote computer is the real thing, doing the right thing? High-end secure coprocessors are expensive and computationally limited; lower-end desktop enhancements like TCPA and the former Palladium have been mainly limited to Windows and proprietary development. In contrast, this code is part of our ongoing effort to use open source and TCPA to turn ordinary computers into virtual secure coprocessors---more powerful but less secure than their high-assurance cousins. Our current alpha release includes the Linux Enforcer Module, a TCPA enabled LILO, and a user-level TCPA library. All source is available from the SourceForge site. The Linux Enforcer Module is a Linux Security Module designed to help improve integrity of a computer running Linux. The Enforcer provides a subset of Tripwire-like functionality. It runs continuously and as each protected file is opened its SHA1 is calculated and compared to a previously stored value. The Enforcer is designed to integrate with TCPA hardware to provide a secure boot when booted with a TCPA enabled boot loader. TCPA hardware can protect secrets and other sensitive data (for example, the secrets for an encrypted loopback file system) and bind those secrets to specific software. When the Enforcer detects a modified file it can, on a per-file basis, do any combination of the following: deny access to that file, write an entry in the system log, panic the system, or lock the TCPA hardware. If the TCPA hardware is locked then a reboot with a un-hacked system is required to obtain access to the protected secret. We developed our own TCPA support library concurrently with, but independently from, IBM's recently announced TCPA library. Our library was an initial component of the Enforcer project. However, our in-kernel TCPA support and the enforcer-seal tool are derived from IBM's TCPA code because of its ease of adaptation for in-kernel use. We plan to use our more complete library for user-level applications. (IBM's TCPA code and documentation is available from http://www.research.ibm.com/gsal/tcpa/.) For more information on our project, see Dartmouth College Technical Report TR2003-471 available from http://www.cs.dartmouth.edu/~sws/abstracts/msmw03.shtml Or contact Omen Wild at the Dartmouth PKI Lab: Omen Wild [EMAIL PROTECTED] -- 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]
