1,367 reputation
1313
bio website
location Madrid, Spain
age
visits member for 1 year, 4 months
seen 14 mins ago

Jun
10
comment Prepend information about encryption implementation to the stored data
@Klathmon - can you cite these resources that claim that keeping the IV secret can be more secure?
Jun
8
comment Prepend information about encryption implementation to the stored data
Appending/prepending metadata to facilitate authentication and/or decryption (such as you've described) is commonplace. The only issue I see is that if you're using CBC mode, then you need to include the IV also, and be sure that this is included in the MAC as well.
May
14
comment CSPRNG in JavaScript using Audio and Video
Speaking of hacky - it's possible to leverage flash APIs via javascript: code.google.com/p/jpegcam . It's more likely that flash will be available on a user's system (excluding iOS, which is a big exclusion) as opposed to window.crypto.getRandomValues(), but if that's the case, then using a webcam might be redundant anyway as flash offers (as of v11) CS random numbers which give direct access to '/dev/random' ... more info here.
May
14
answered CSPRNG in JavaScript using Audio and Video
Apr
10
revised What does “adaptively secure” mean?
Corrected the title's grammar
Apr
10
suggested suggested edit on What does “adaptively secure” mean?
Apr
8
comment Given a certain entrophy per character, how long should a passphrase be to guarantee key strength?
This Wikipedia article is a good resource.
Apr
7
comment Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
That makes sense - thanks for clearing it up.
Apr
7
comment Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
Part of the question asks; "how is the mode of operation transmitted along with the encrypted file?". If you don't think I've answered that succinctly, then keep your upvote. If you think my answer is dangerously-misinformative, then downvote me. But frankly, I don't see much of a distinction between "Most systems have a predefined mode of operation", and @Poncho's assertion that "the mode of operation isn't usually explicitly transmitted in the ciphertext", yet I don't see you nitpicking his answer.
Apr
7
comment Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
I see what's going on here...
Apr
7
comment Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
Would encrypting the mode and algorithm add any significant security in the context you mentioned? Or is it simply a matter of convenience to store the mode/algo with the encrypted key (which must be encrypted)? I had understood that encrypting non-sensitive data (such as an IV, mode, etc) is generally discouraged.
Apr
7
comment Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
I would quantify 'most systems' as there being more systems (at a guess) that use pre-defined protocols (version-dependent or otherwise) than those that don't.
Apr
6
answered Do I need to know the “mode of operation” to decrypt a message encrypted with a block cipher?
Apr
5
comment How can mega store my login details and still be secure?
Be reasonable. Nobody is asking anyone to reverse-engineer anything. If participants in this forum (especially new ones) can't ask questions such as: "How can they (mega) do this without compromising their encryption?" without being told to go away and ask someone else, then what is the point of the forum?
Apr
5
revised How can mega store my login details and still be secure?
trying to mitigate a $hit$torm
Apr
5
comment How can mega store my login details and still be secure?
"Doubly incorrect", you mean, like a double-negative? "Too time-consuming" is subjective, it depends on the attacker's patience, and what is known about the encrypted data. Anyway, in the interest of putting an end to this insufferable thread, I've edited my answer. Downvote if you disagree.
Apr
5
revised How can mega store my login details and still be secure?
trying to mitigate a $hit$torm
Apr
4
comment How can mega store my login details and still be secure?
And by the way - you're right about that link - the answer assumes brute-forcing 256 or 512 bits of high entropy psuedo-random data, but in fact the question is in regard to brute-forcing a low-entropy password.
Apr
4
comment How can mega store my login details and still be secure?
I was referring to using something like SHA256 or SHA512 as the underlying algorithm for a PBKDF, (as per my original answer), but re-reading, I can see that I should have made that clearer in my comments.
Apr
4
comment How can mega store my login details and still be secure?
Well yes, regardless of the hash algorithm used (MD5, SHA512, Keccak, or whatever), if the password is only 8 characters long then brute-forcing it would be trivial. Using a slow-hash such as PBKDF2 or Scrypt was mentioned in my answer, but given all this talk about brute-forcing hashes, it's worth underscoring it.