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seen Aug 16 '13 at 18:37

Generalist. Systems guy. Security Engineer. Frequent schneier.com contributor.


Apr
13
awarded  Yearling
Aug
11
answered Tor via Python - can the real IP address leak?
Jul
21
answered How does storing GPG/SSH private keys on smart cards compare to plain USB drives?
Jul
21
answered What would be the application-level equivalent of dynamic communication secrets?
Jul
14
comment How does formal verification guarantee secure, error-free code?
Actually, that's inside the scope. The scope is an isolation kernel with control of CPU, memory and IPC flows. Such a proof shows that, with certain restrictions on the code, anything it does won't render the system unsafe beyond that code's partition. Proving more than that requires more effort. Which is the point of isolation kernels: you only pay for what you use in the final system.
Jul
14
comment How does formal verification guarantee secure, error-free code?
I do agree with you, though, that sh4d0w is just extrapolating what happens with poorly assured software to software that used formal methods. I also haven't heard of any 0-days found in a product verified down to the code.
Jul
14
comment How does formal verification guarantee secure, error-free code?
CompCert was formally proven. It had errors in the front end and back end IIRC. One Orange Book A1 used DES for MLS enforcement. Many formally proven codes also assume hardware works correctly. It often has bugs that can affect security. That goes all the way back to MULTICS days and certain intel chips have MMU issues. Then there's the cases where the verifier/prover don't work right. Those issues have occurred in the past.
Jun
15
awarded  Commentator
Jun
15
comment Can a hard drive be destroyed by drowning?
For D3C4FF. You have to get the mixture right. Look up Skunkwork's thermite presentation for help in that regard. His was thorough and datacenter safe. ;)
Jun
4
comment How secret are secret forums?
It's of smaller use than the other suggestions. Many people don't like leaving all their private information on a server that might be used by another person. Anything stored on a regular filesystem is still there upon delete. This can be picked up by the next user, by a drive thief, etc. Encryption by default eliminates these and other worries. You're right that a person might screw up a backup. Yet, truecrypt is very reliable and using it means the entire forum (maybe software too) can be backed up by downloading one file: the volume. (Or a diff of it.) OP can leave crypto out if desired.
Jun
4
answered AppEngine Sandbox
Jun
4
answered Can a hard drive be destroyed by drowning?
Jun
4
answered How to validate if a JavaScript library is secure?
Jun
4
answered Is it worth following OWASP AppSensor for an open source web application?
Jun
4
answered How secret are secret forums?
Apr
28
comment Using MD5 for file integrity checks?
Short answer: no. Long answer: we can't believe any construction is secure unless its been analysed and proven over time. A specific, truncated SHA-256 output? Hopefully secure, but no proof. MD5 for 2nd preimage attacks? Decent in theory and proven in 20+ years field use. MD5's speed and digest size trumps SHA256. I mean, an opponent good enough to second preimage MD5 in coming years could penetrate your system in dozens of easier ways. That's my whole point. Certain crypto issues get more focus than they deserve.
Apr
19
comment Using MD5 for file integrity checks?
We can. However, this could affect the security properties of the resultant hash. Uniqueness would be my main concern. Cryptographers in the past have warned me against customizing crypto algorithms and being clever with them. So, the non-clever solution was using a compact, superfast, well-understood algorithm that will survive this use case, if not others.
Apr
18
comment Remote System Administration of an Encryption-Switch-Encrypted Infrastructure
then hopefully my answer will help
Apr
18
comment Is Using MD5 Sufficient Reason to Reject This Payment Processor?
I assumed an HMAC. It's good that you explicitly said it, though.
Apr
18
comment Can Skype chat be protected from snooping? Are there safe alternatives?
Yeah they have a nice solution. I probably forgot to mention it b/c I got into it with the company over their marketing. They kept implying their hiring Navy SEALs meant something about their product's security. I slammed them for it.