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Mar
20
comment HMAC tag to verify the key (verification in the reverse direction)
Universal hash families provably achieve your goal. $\;$
Mar
18
comment Applying Trapdoor Function directly to plaintext
@Nova : $\;\;\;$ My "attack also works with a hashed input", however, I don't see why that makes the scheme mentioned in hvuong91's comment at 04:45:27Z insecure. $\:$ (Is "his/her mentioned scheme" different from that one?) $\;\;\;\;\;\;\;\;$
Mar
18
comment Applying Trapdoor Function directly to plaintext
@Nova : $\;\;\;$ Perhaps, but in any case, I hadn't noticed that comment. $\:$ "Why does" what "become insecure if we don't do that"? $\;\;\;\;\;\;\;\;$
Mar
18
comment Applying Trapdoor Function directly to plaintext
@Nova : $\:$ No, hvuong91 didn't say that hashing was the alternative. $\;\;\;\;$
Mar
18
comment Applying Trapdoor Function directly to plaintext
@Nova : $\:$ The eavesdropper would first hash candidate before using the trapdoor function. $\hspace{.69 in}$
Mar
18
comment Applying Trapdoor Function directly to plaintext
I just did that. $\;$
Mar
18
revised Applying Trapdoor Function directly to plaintext
gave a simple example
Mar
18
comment Making PRFs out of PRGs
Do you mean $\: n\cdot 2^{\hspace{.02 in}n} \;$? $\;\;\;$ (Instead of $\: n.2^n \;$.) $\;\;\;\;\;\;\;\;$
Mar
18
answered Applying Trapdoor Function directly to plaintext
Mar
17
revised Reusing a one-time pad?
fixed title's spelling
Mar
17
revised Can we reverse a hash when we know part of the input?
fixed two typos
Mar
13
comment Attack on key exchange with authentication
Is "it" the random k or H(pk) or pk or the ciphertext resulting from encrypting the random k with H(pk)? $\hspace{.23 in}$
Mar
13
comment Attack on key exchange with authentication
"read it off to Alice", where "it" is ... $\;$
Mar
8
comment What work goes into creating new asymmetric cryptosystems?
Is Diffie-Hellman an "RSA-like algorithm"? $\;$
Mar
7
comment Separate keys for encryption and MAC?
One "solution is to derive the encryption key and the MAC key from a single master key, using a KDF." $\hspace{.24 in}$
Mar
7
revised How do SignRecover and VerifyRecover work?
fixed grammar
Mar
6
comment Is there a format preserving cryptographically secure hash?
1&2 is easy. $\:$ Rank-then-hash-then-unrank can plausibly do 1&2&3 against uniform adversaries.
Mar
5
revised Is the reduction from left-or-right IND-CPA to real-or-random IND-CPA tight?
inserted length requirement
Mar
4
answered Is the reduction from left-or-right IND-CPA to real-or-random IND-CPA tight?
Mar
4
comment What is the advantage of using the socialist millionaire protocol to authenticate vs HMACing some random number?
For that, either $C$ would need to be fixed-length or both $r_1$ and $r_2$ would need to be fixed-length. $\hspace{.53 in}$