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1d
comment Public key encryption without ciphertext expansion
crypto.stackexchange.com/q/9140/991 $\;$
1d
comment Password generation/storage scheme
How is somesite.com "hashed together with K"? $\;$
2d
comment Encryption algorithm designed to be easy to decrypt by machine but impractical to decrypt by hand
I'm guessing this is supposed to be a heavy-duty analogue of ROT13. $\;$
Oct
26
comment Isn't Groth-Sahai proof system applicable beyond Bilinear groups?
What is PPE? $\:$ What are MSME and QE? $\;\;\;\;$
Oct
26
comment A one way Function provably reversible at N applications with the same seed?
No, I was suggesting that f be evaluation of s at A, where s is a polynomial of degree at most N-1. $\:$ However, I now realize that the decoder also needs to know what the finite field is. $\hspace{1.45 in}$
Oct
26
comment A Doubt with the twisted-PRF
"So", that's why they don't claim that the existence of a PRF implies the existence of one for which the "Original Twisted PRF Trick"'s F would be insecure. $\:$ (For some reason, it won't let me log in to chat.) $\hspace{.32 in}$
Oct
26
comment A Doubt with the twisted-PRF
"the problem of original twisted PRF" $\;$
Oct
26
comment Infer encoding mechanism from $n$-grams distance?
Can you get the encodings of arbitrary strings? $\;$
Oct
26
comment A Doubt with the twisted-PRF
Do you have something which you think is a better way to show that? $\;$
Oct
26
comment A Doubt with the twisted-PRF
There are certainly "problems with the proof in ... PRF Trick"; that's the paper's point. $\hspace{1.32 in}$
Oct
25
comment A one way Function provably reversible at N applications with the same seed?
Do you want s to remain hidden against an essentially unbounded number of queries that don't include any such chains, or just against less than N total queries? $\;$
Oct
25
comment A one way Function provably reversible at N applications with the same seed?
"being reversible at some step N" in the sense of revealing the original A or the immediately preceding A? $\;\;\;$
Oct
24
comment Large file validation on an embedded system through hash and encryption
It would probably be better to sign "the MD5 hash with a private key and return" a signed "hash to the embedded system", rather than trying to use encryption for that purpose. $\;$
Oct
24
comment Secure way to derive separate encryption and MAC keys from a single master key?
@owlstead : $\;\;\;\;$ "for less structured" $\: \mapsto \:$ "for more structured" $\;\;$ ? $\;\;\;\;\;\;\;\;\;$
Oct
24
comment Operation which needs much computing power to be created, but just a little to be solved?
The "just a little to be solved" part is easy: declare that 0 is always a solution. $\;$
Oct
23
comment Operation which needs much computing power to be created, but just a little to be solved?
@StephenTouset : $\:$ How? $\;\;\;\;$
Oct
23
comment How to compute 3P from elliptic curve where P is (28, 8)
... for what EC group? $\;$
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
I would recommend using HMAC, since it is presumably a secure PRF. $\:$ I have no idea what the impact on performance would be. $\;\;\;\;$
Oct
20
comment Can we run a probabilistic function on ciphertext with Functional Encryption (or Attribute Based Encryption)?
@TravisMayberry : $\:$ That depends on what the PRF takes as input. $\;\;\;\;$
Oct
20
comment Can we run a probabilistic function on ciphertext with Functional Encryption (or Attribute Based Encryption)?
@JianLiu : $\;\;\;$ If $sk_f$ can be quantum, then it might be possible "to prevent Bob from providing the same randomness to $\hspace{.04 in}f$" every time. $\:$ There are non-deterministic PRNGs, but that would just move the problem to preventing "Bob from providing the same" entropy to the PRNG every time. $\:$ Do invoker-randomizable PRFs count as "non-deterministic"? $\;\;\;\;\;\;\;$