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seen 22 hours ago

May
15
comment Security of several files all using same password/key (7zip, AES256)
More specifically, in a real worst case scenario, the chaining mode won't matter. Chaining only means that the current state depends on the previous iterations of the algorithm. If the first phrase of the encryption is able to be broken, then any subsequent ones could still be broken though and the IV is going to be known since the IV is not protected data. It is the job of the algorithm to ensure that you can't figure out the key from a set of plaintext and cipher text.
May
15
comment Security of several files all using same password/key (7zip, AES256)
@Ángel- um, no... what you describe is a KPA (known plaintext attack). There currently isn't any major KPA against AES (at least not that I've heard of). There are stronger and weaker block modes for other attacks, but you are talking specifically about KPAs and drastically failing KPAs, of which there are none for AES currently.
May
14
comment Security of several files all using same password/key (7zip, AES256)
@angle - If knowing the plaintext and ciphertext gives away the key, your algorithm is SERIOUSLY broken. Note that I specifically indicated that my answer is only relevant if the key selection and encryption algorithm is strong.
May
6
awarded  Nice Answer
Apr
11
comment Now that CloudFlare offers potentially-insecure free SSL to all users, would a new HTTP header be useful?
@Rushyo - are you saying that Comodo actually gave cloudflare access to their root pki keys? That would be very bad and would be worth stopping trusting them. (Other CAs have been delisted for compromise of the private keys.) Much more likely would be that they signed a code signing key for Cloudflare and you could simply decert the specific delegated key to break chain of trust. IT wouldn't block 90% of the internet, it would only break the certs that Cloudflare generates.
Apr
10
comment Now that CloudFlare offers potentially-insecure free SSL to all users, would a new HTTP header be useful?
@Rushyo - in the case of a load balancer, it should be load balancing across either a physically secure network or should be re-encrypting to the end point. The problem is only when you label something as a secure connection that is not. Providing an SSL gateway to a non-encrypted site across the open internet is a very different thing from providing a load balancer in a secure data center that acts as the SSL head.
Apr
9
awarded  man-in-the-middle
Apr
8
awarded  Enlightened
Apr
8
awarded  Nice Answer
Feb
22
comment Create certificate without private key with OpenSSL
Can't you use the smart card to sign the CSR? Simply produce the unsigned CSR and then submit it to the card for signing. Signing is typically a feature of a smart card since without being able to sign, it can't prove to anything that it has the private key.
Feb
15
comment Why don't mobile operators blacklist stolen phones using their IMEI?
Fair enough, but a permanent fix still isn't a concern for a thief. They just want to get the cash. They are almost never the end user, because they know having stolen property is a bad idea.
Feb
15
comment Why don't mobile operators blacklist stolen phones using their IMEI?
I'm not sure if it is possible to clone with a jtag or similar device against the hardware directly, but a thief doesn't care if it works long term. They care if they can pawn it off on someone before it breaks.
Feb
14
comment Can you say that since one time pad encryption is unbreakable, it is the best if used properly?
@chao it is worth pointing out that using crypto all the time doesn't hide that you sent a message, it just hides if it is interesting. Also, otp isn't limited to the Internet so it could be used through covert channels that are harder to track to you.
Feb
14
comment Why would an attacker try to guess random email usernames on a small domain?
@skaperen Actually there is zero chance because they try the same series of passwords and are blocked before they ever get to a valid password since the initial guesses don't meet complexity requirements.
Feb
14
awarded  Good Answer
Feb
14
comment Can you say that since one time pad encryption is unbreakable, it is the best if used properly?
@Hopelessn00b - Ok, re-reading your comment from earlier, I think I get what you are saying about OTP not maintaining perfect information security (sorry, it is 2am here). It does leak that you may have sent a message (but you may not have). But that in no way aids in breaking the cryptography itself. My statement is very clearly about being "impossible to break", not "impossible to make any observation about your action". There is no information leaked which is useful in breaking the cryptographic protection of the message.
Feb
12
awarded  Nice Answer
Feb
11
answered Can you say that since one time pad encryption is unbreakable, it is the best if used properly?
Jan
8
reviewed Close Ruby OpenSSL vs Linux openssl
Jan
8
reviewed Close How do I avoid drawing the ire of the Department of Homeland Security when prepping to run my RPG?