484 reputation
27
bio website chiark.greenend.org.uk/~armb
location Cambridge, UK
age 50
visits member for 2 years, 2 months
seen 2 days ago

Apr
15
comment Why does the user pick the password?
@Vality - that's not entirely true. If I pick a weak password on a web service, anyone in the world can try and guess it. If I use a strong password and write it on a post-it note on my monitor at work, a very small number of people I generally have to trust anyway have access to it. If I write it down in a password manager application that's protected by a password I don't write down, it's even harder for anyone else to access.
Mar
26
comment Hide the fact of e-mail communication
@vojta - I think that "when not overcoming any obstacles" is a spurious qualification, and that the UK's Computer Misuse Act 1990 doesn't say anything about overcoming obstacles to gain unauthorised access anyway. There are situations where Eve might have authorised access to all the potential girlfriend's mail and is merely abusing it, but it's unlikely.
Mar
25
comment Hide the fact of e-mail communication
I know you said divorce is not an answer, but Eve monitoring Alice's mail (and all the other potential girlfriends) is almost certainly a criminal offence. Bob can probably use that as justification for a divorce, and once Alice is in jail she can't monitor Bob any more.
Mar
25
comment Hide the fact of e-mail communication
@sebleblanc But with the problem as stated, Alice will start suspecting Bob is married if he stops using the email address she (and Alice) already know as Bob's. Even if her boss is also called Bob, the pseudonym is going to be hard to pull off without Eve actively co-operating.
Mar
20
comment Can an old operating system webserver be made secure?
He could run a user-space TCP stack and ignore the OS one completely, at least in theory....
Mar
18
comment Is it possible to wrap and export RSA private key in FIPS 140-2 Level 3 compliant hardware?
Sorry, I don't have any suggestions. But at least you now have an existence proof that a PKCS#11 implementation can allow unbounded private key export, only protected with an externally provided AES key, with a FIPS 140-2 level 3 HSM.
Mar
18
answered Is it possible to wrap and export RSA private key in FIPS 140-2 Level 3 compliant hardware?
Mar
13
comment Is it legal to start a private website for you and your friends to hack?
As well as the free level of CTF365, you could try microcorruption.com/about (and/or forthcoming kalzumeus.com/2015/03/09/announcing-starfighter)
Mar
13
comment Why for some SSL websites browsers show extra info, while for others dont
Might be worth adding an explicit statement that "EV" stands for "Extended Validation", and there are guidelines for them defined by the CA/Browser Forum, so CAs and browser manufacturers agree what is meant. en.wikipedia.org/wiki/Extended_Validation_Certificate
Mar
9
comment How to estimate the time needed to crack RSA encryption?
Some years later, 512 bits is down to "about 7.5 hours": blog.cryptographyengineering.com/2015/03/… (Typical users still aren't anywhere near breaking 1024-bit keys, and won't be within the remaining time of the "ten years" of the answer. The sort of organizations who might possibly be don't make public announcements: crypto.stackexchange.com/a/1982/5249)
Jan
31
awarded  Yearling
Jan
2
comment How can I know that the CA certificates in my computer have not been spoofed?
They don't have to manipulate the browser, they can edit the results page from GRC so that they appear to match. That's unlikely, but to test against it you need to compare with a machine outside the employer's network. (Also, there are legitimate (but unlikely) scenarios where you will get a mismatch - if the site is actually using multiple load balanced servers around the world, they could use different valid certificates for different machines. Or a server might have both RSA and ECDSA signed certificates, and your browser use one that GRC doesn't ask for.)
Oct
20
comment How can I know that the CA certificates in my computer have not been spoofed?
Thanks - link fixed
Oct
20
revised How can I know that the CA certificates in my computer have not been spoofed?
Updated dead link
Oct
15
comment SSL3 “POODLE” Vulnerability
The SSL 3.0 symmetric cipher that doesn't use CBC mode is RC4, which may well be disabled for reasons also well explained by Thomas (and the NULL "cipher") - security.stackexchange.com/questions/32497/tls-rc4-or-not-rc4/…
Sep
17
comment Trying to understand why signatures in root certs “are not used”?
Or, from the other direction, if you can alter the root certificate store (for example by saying "employee, install this corporate root certificate if you want to keep your job", or by patching the browser), you can insert your own certificate regardless of which signature algorithm you use, and regardless of which algorithms legitimate CA certificates used.
Jul
10
comment Generic error message for wrong password or username - is this really helpful?
You could do it this way if your per-row salt was generated from the user name, say by feeding it into HMAC with a secret key. Obviously to avoid timing attacks you need to make sure the password hashing is done whether the username exists or not, but that's trivial.
May
22
comment What's to stop someone from 3D print cloning a key?
I know someone who works in a prison, and he once said he knew several prisoners capable of making a working copy of a key from having seen it across a room.
May
12
comment Key management in cloud datacenters
If the keys are kept on an HSM, VMs snooping on each other won't see the actual key operations. However technet.microsoft.com/en-us/library/dn440580.aspx suggests that all the HSM protected keys in a datacenter are in the same Security World, and that the "Bring Your Own Key" management still needs the key to be exported from your own world into Microsoft's. Security Worlds do allow separation of key protection within the world though, so other users shouldn't be able to use your keys.
May
2
comment Key management in cloud datacenters
Apparently the Microsoft Azure key import used to require you to fly to Redmond yourself, but that's no longer the case: blogs.technet.com/b/rms/archive/2014/03/05/…