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 Yearling
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  • 0 posts edited
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  • 37 votes cast
Mar
15
comment What is Deterministic Authenticated Encryption?
Opposite to nonce based authenticated encryption, DAE takes as input only the associated data, the plaintext and the key and outputs a ciphertext. SIV is a good example of this. The point is to use such primitives in a context where the use of a IV is rendered irrelevant because the plaintext distribution is of high entropy (such as key encryption)
Mar
11
comment Would a non-deterministic (read: randomized) compression algorithm be crypto-safe?
If you pad, what's the point of compression ?
Mar
11
comment Would a non-deterministic (read: randomized) compression algorithm be crypto-safe?
Are you in any way referring to the TLS attacks built upon the usage of compression pre-encryption ? If you are then I don't think your solution would help since either your "added randomness" increases the size of the ciphertext and then it defeats the purpose of using encryption or it doesn't and then the BREACH and C.R.I.M.E attacks can proceed as usual since they are mainly focusing on the size of the outputted ciphertext
Mar
11
comment Would a non-deterministic (read: randomized) compression algorithm be crypto-safe?
"so why not compress your file and then encrypt / send it using a stock TLS library like openssl" This is not a good idea... SSL/TLS optionally includes compression of the plaintext before encryption. The problem you open yourself to active attacks such as BREACH or C.R.I.M.E which are some of the most efficient attacks on SSL/TLS.
Oct
24
awarded  Yearling
Sep
10
comment Implement AES with 16 bit block size?
could you please provide a reference for the 24 round unbalanced festeil you're writing about ? Thx
Sep
7
answered Could someone explain the given algorithm?
Jul
12
comment Why Elliptic Curves?
very good point !
Jul
9
comment Does SHA-1 meet the strict avalanche criterion?
This technique is efficient to weed out very bad hash function candidates but I doubt it will tell you anything about SHA-1. There was a lot of work put in finding flaws in SHA-1 by actually looking at SHA-1. I don't think you can really expect finding anything looking at SHA-1 as a black box.
Jul
7
comment Does SHA-1 meet the strict avalanche criterion?
I haven't and I don't really see the point : You're only ever going to look at a infinitely small portion of the input space. What this means is that this method doesn't answer your original question which was : "Does SHA-1 meet the strict avalanche criterion?"
Jul
7
comment Does SHA-1 meet the strict avalanche criterion?
Did you do the math on how much computation you would need to do for SHA1 given that its input space consist of all message whose length is smaller than 2^64 ?
Jul
5
answered Do all attacks against PKCS1 v1.5 encryption require an oracle
Jun
23
awarded  Caucus
Jun
23
awarded  Constituent
Apr
14
comment Errata for NIST SP 800-63
Those figures assume that humans pick password randomly. Whether or not the calculus is fine matters less than the fact that this assumption is overly optimistic and should be nixed from any serious document !
Feb
4
comment How fast would a polynomial time factoring algorithm compute?
Maybe that's nitpicking but the distinction is polynomial vs. non-polynomial rather than polynomial vs exponential. We know subexponetial algorithms to factor large numbers as well as finding discrete logarithms in finite fiels.
Oct
24
awarded  Yearling
Mar
4
comment Why does CTR mode XOR the plaintext into the output of the block cipher rather than XORing the plaintext into the input of the block cipher?
CTR is designed in this way as a technical equivalent of One TIme Pad where the full entropy random keystream is replaced by a pseudo random generator
Feb
13
comment Pseudo random permutation for arbitrary size domains
If I may extend the question of the OP the paper you cited states that their methods aren't suitable when the domain $X$ is such that $2^{30}<|X|<2^{60}$ and presents that gap as a open problem. Are you aware of subsequent research that solved ?
Jan
8
comment Would data be secure if a cryptographically secure PRNG was used for encryption?
Two things : First it would be somewhat pointless to do on top of AES-[insert-right-mode-of-operation-here] but as long as the AES layer and the PRNG layer are uncorrolated it won't decrease security. Also what you get from your solution is confidentiality which is great but in many situations not enough. For example what is the consequence of a bit flip by an attacker on ciphertext in transit ?