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Apr
6
comment How is HMAC(message,key) more secure than Hash(key1+message+key2)
@fgrieu : $\:$ (I realize it's been over a year, but) One could consider SHA256(key1+message+padtoblockboundary+key2) instead. $\;\;\;\;$
Apr
6
comment Hash functions to the power of two and three notation
Yes. ${}{}{}\;$
Apr
4
comment Will ANY prior knowledge assist in determining contents of a SHA1 hash?
"that hash" $\: \mapsto \:$ "that data" $\;\;\;$ ? $\;\;\;\;\;\;\;\;$
Apr
4
revised Will ANY prior knowledge assist in determining contents of a SHA1 hash?
fixed grammar
Apr
3
comment Solve a problem, thought it was hash length extension, hours later, am I wrong?
stackoverflow.com/questions/6961208/… $\;$
Apr
3
comment Solve a problem, thought it was hash length extension, hours later, am I wrong?
Can YouKnowMe contain a null character? $\:$ If no, then the only attack I can think of would require that key:known_value:nonce be more than 2^53 bytes long. $\;\;\;\;$
Apr
3
comment Solve a problem, thought it was hash length extension, hours later, am I wrong?
Oh, yeah, it's more difficult than I thought. $\:$ You would probably need the padding anyway. $\:$ Does the application use unicode or just ascii or something else? $\:$ Can YouKnowMe contain the character Ç? $\:$ What about null characters? $\;\;\;\;$
Apr
2
comment Are there any valid, and person readable, checksums possible?
readable $\mapsto$ memorizable $\:$ ? $\;\;\;\;$
Apr
1
comment Is it safe to encrypt random data using ECB mode?
@SAI Peregrinus $\:$ : $\:$ For most current ciphers, 48 bytes is more than block size. $\hspace{1.55 in}$
Mar
31
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
His salt is far from "entirely pointless". $\:$ Salts can be used to defend against time-memory tradeoffs. $\hspace{.2 in}$ How could Eve "decrypt everything afterwards"? $\;\;\;\;$
Mar
31
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
"will be" $\: \mapsto \:$ "will not be" $\;\;\;$ ? $\;\;\;\;\;\;\;\;$
Mar
28
comment Stacked LFSR - why not used?
The alternating step generator is close-enough that I doubt there's a name for your generalization. $\hspace{.59 in}$
Mar
28
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
(Note that your most recent edit does not fix the problem.) $\;$
Mar
28
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
That still does not work with the standard meaning of "know". $\;\;\;$ With any standard meaning of "know", Mallory could know $\: A_{\hspace{-0.02 in}1}\hspace{.03 in}||\hspace{.04 in}A_2 \:$ without knowing $A_{\hspace{-0.02 in}1}$ and without knowing $A_2$. $\;\;\;\;\;\;\;\;$
Mar
27
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
... In that case, you should mention that you're using a non-standard definition of "know". $\;$
Mar
27
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
You should put that into your opening post. $\;$
Mar
27
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
That wouldn't "qualify it as 'secure'". $\:$ Similarly, my "argument could also be used to say public" key encryption is "insecure, because it allows you to check your guesses for the private key." $\:$ (Both of those sayings would hopefully be incorrect, since it's supposed to be infeasible to guess the private key.) $\hspace{.33 in}$
Mar
27
comment Is this a valid scheme to authenticate through a 'human-readable' certificate?
No, since that would let Mallory check her guesses for the concatenations of the answers. $\hspace{1.03 in}$
Mar
25
revised Does perfect secrecy imply uniform ciphertext distribution?
explained non-uniformity
Mar
25
answered Does perfect secrecy imply uniform ciphertext distribution?