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comment can non assembly crypto libraries truly be secure against timing attacks?
You can't really control what's in the L1/L2 cache with assembly; that also depends on interrupts the CPU takes, and what the other cores are doing (neither of which are under the user's control). If you controlled the operating system as well, you would have hope; however I believe that's focusing in on the wrong question; the answer to timing attacks isn't having precisely consistent timing, but have any variation in the timing uncorrelated to any secret we have.
10h
reviewed No Action Needed Signature Verification: High level
10h
reviewed No Action Needed Understanding elliptic curve encryption
14h
revised Implementing CBC Encryption Using Decryption
edited tags
14h
answered Implementing CBC Encryption Using Decryption
1d
comment Encryption algorithms larger than 256 Bit for “big data” encryption?
Are you asking "why do we generally restrict our (symmetric) keys to 256 bits"? If you aren't asking that, what are you asking?
1d
answered How AES treat string input to encrypt data and what will happen if the cipher key is less than that expected?
1d
comment One time pad ciphers in emails
The "keyword"??? If you're doing OTP, you don't distribute a keyword; instead, you distribute a random string of bits at least as long as the message you'll be sending...
1d
comment ElGamal in $Z^*_{p^n}$
Another way (and, it turns out, an equivalent way) of looking at it is that if we know that if we have a solution for $a^x = b \bmod 3^n$, then we can easily find a solution for $a^x = b \bmod 3^{n+1}$; hence we can start with $n=1$, and work our way up.
2d
reviewed Approve Is there a proof for showing any cryptogram is crackable?
2d
reviewed Approve Simply put, what does perfect secrecy means?
2d
reviewed Leave Closed What is the definition of “the correlation” and “the difference propagation probability”?
2d
answered Can we solve the Hidden Number Problem in $GF(2^n)$?
Jul
29
comment I don't know whattype of cipher this is
My guess is that it's some sort of transposition cipher (the letters are rearranged)
Jul
28
revised Is Paillier cryptosystem commutative?
Paillier addition is not a field operation (the power is a non-prime-power). It is a group operation, and that sufficies.
Jul
28
answered In which step does AES use the key to encrypt data?
Jul
27
comment Library to find an addition chain for a large number?
What do you mean by 'good'? The simple-minded binary method gives a decent one (within 50% of optimal for random inputs), and is completely trivial to compute. If that's not good enough, how close to optimal are you demanding?
Jul
27
comment Permuting Small Sized Set in Practice
I believe you need to rethink what security means in this context. It doesn't mean that the attacker can't take a guess at the permutation (and have a $1/|S|!$ chance of getting it correct). Instead, it's that the attacker doesn't get any additional information about the permutation. That is, even if $|S|=2$, the attacker knows that either the two elements remain where they are, or that they are swapped; but he doesn't know which it is.
Jul
27
answered Reduction to cdp,dl or cdh?
Jul
27
comment Reduction to cdp,dl or cdh?
Where does the randomization come into play? $f(x) = g^{sk \cdot x} \bmod p$ (for fixed $g$, $sk$, $p$) looks determanstic.