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May
15
answered Is what i'm trying to do safe?
May
6
comment Brute-force attack given small search-space and hash prefix
This answer is incorrect. It assumes we only have 8 bits of the hash, but as the OP has clarified, we actually have 32 bits of the hash.
May
6
comment Brute-force attack given small search-space and hash prefix
I encourage you to edit the question to incorporate this information. Comments exist to help you improve the question; clarifications shouldn't be left in the comments, as they can disappear at any time, and readers shouldn't need to read the comments to understand what you're asking.
May
6
answered Brute-force attack given small search-space and hash prefix
May
6
comment Brute-force attack given small search-space and hash prefix
What's a character, in terms of bits, in your implementation? Is the output of sha1_hex() in hex, so each character is 4 bits of the hash, and the first 8 characters are the first 32 bits of the SHA1 hash?
Apr
27
comment Can cycle finding techniques reduce the memory usage of the MitM attack against 2DES and 3DES?
Yes, it works. It's a standard trick; kudos for re-discovering it. I see no reason the table size would amount to $2^{n/2}$. The complications in working out exact parameters arise when you work out the details of (a) parallelism, (b) distinguished points, (c) the cost of memory and routing networks, to get the exact optimal tradeoff (if you care about constant factors).
Apr
26
comment Adding two public keys
@RickyDemer, I don't know. I guess that's a different question. If you're suggesting that might be what the OP wanted, if so, he needs to specify his requirements or goals in the question. Right now the question only asks for "another, more widely used" scheme. I can only answer the question that was asked....
Apr
26
comment Is there are code hidden in Wired Magazine's December 2014 Issue?
@jww, are you sure you've got the right site? This question is clearly off-topic for PP&CG: codegolf.stackexchange.com/help/on-topic
Apr
26
answered Adding two public keys
Apr
15
awarded  Popular Question
Apr
9
awarded  Guru
Apr
8
awarded  Nice Answer
Apr
5
comment Will ANY prior knowledge assist in determining contents of a SHA1 hash?
@InfernusDoleo, you'll be fine, if that 26-character secret key is truly secret and chosen uniformly using a crypto-quality randomness source. That large secret key means that the space of candidate inputs is very large, so brute-force won't work. The fact that you can see many outputs with related inputs doesn't help given that the secret key is so large.
Apr
4
comment Will ANY prior knowledge assist in determining contents of a SHA1 hash?
@InfernusDoleo, I can't answer that, because it's not clear what you intend the full input to the hash to be. If you want a more detailed answer, list all the parts of the input to the hash and what is known about each. An incrementing nonce counts as a known/predictable part of the input, since it can be predicted.
Apr
4
answered Will ANY prior knowledge assist in determining contents of a SHA1 hash?
Apr
4
comment Will ANY prior knowledge assist in determining contents of a SHA1 hash?
You mean knowing some of the input to SHA1, or knowing some of the output? (you talk about knowing parts of the hash, but usually when we say "the hash" we mean the output of SHA1, not the input)
Apr
1
comment How can mega store my login details and still be secure?
@tagyro, thank you for the pointer. Unfortunately, a source code repository is not a substitute for a design document that describes how the architecture addresses these threats. (That said, from xemacs' answer, it sounds like they did exactly what I speculated in my answer.) I think the links to vulnerabilities in early versions of the system are relevant to understanding the history of the system. If there are public documents that respond to that analysis and explain why they're wrong or how they've been fixed, with technical details, I'd gladly update my answer with that information.
Mar
28
awarded  Nice Question
Mar
27
reviewed Approve Practical brute-force attack on 128 bit encryption
Mar
25
answered Discrete log accumulator without pairings