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Dec
15
comment Execution time for HMAC-MD5 on a 160 bit data using 128 bit key on a 3GHz CPU
@MaxthonChan I used the cost for hashing 64 bytes (2 blocks) from SUPERCOP on a modern Intel CPU. Since HMAC with fixed key hashes 2 blocks as well, that should be a reasonable approximation.
Dec
15
comment Lightweight Asymmetric encryption algorithm
You should also consider elliptic curves. A popular and relatively fast choice is Curve25519, but there are even faster curves.
Dec
14
comment Execution time for HMAC-MD5 on a 160 bit data using 128 bit key on a 3GHz CPU
Perhaps 800 CPU cycles if the key is fixed, twice that if it is not. That corresponds to about 0.3 µs on zour 3 GHy CPU. Details depend on the CPU in question. See eBASH
Dec
12
reviewed Approve Message exchange with textbook RSA
Dec
12
comment How much stronger is RC4 if it is keyed with an RSA private key?
@poncho Wouldn't a sufficiently large key eliminate the bias in the beginning of the RC4 stream caused by its weak key setup, leaving only the mostly harmless n-gram biases inherent to RC4? (of course one could just drop the beginning of the output instead)
Dec
8
comment How to test the speed of an Authenticated Encryption algorithm?
Take a look at SUPERCOP. It's a popular benchmark framework for CPU based benchmarking.
Dec
7
revised Deletion in RSA Accumulator
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Dec
7
revised Deletion complexity in a RSA accumulator
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Dec
7
comment Deletion complexity in a RSA accumulator
When you say O(1) you mean with respect to the number of elements in the accumulator, right? Because the cost obviously increases with increasing modulus size.
Dec
7
comment 2 Part Encryption
Take a look at D. Boneh and M. Franklin - An efficient public key traitor tracing scheme a paper presenting a traitor tracing scheme.
Dec
7
comment 2 Part Encryption
So you want traitor tracing when a key gets leaked? In that case you might be interested in broadcast encryption. Or why is using the same key problematic?
Dec
7
comment Applying Vigenere on small strings with sorting capability
How about plaintext? Seriously, if your crypto is that weak, you might as well not use any.
Dec
6
comment Applying Vigenere on small strings with sorting capability
Related: How does order-preserving encryption work?
Dec
6
comment Why Merkle Tree doesn't suffer Birthday attack?
Birthday attack against what? Collision resistance? All hashes suffer from that one, including merkle-trees, that's why we need 256 bit hashes for 128 bits of collision resistance.
Dec
6
awarded  Popular Question
Dec
5
revised Probability approximation of no collisions
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Dec
5
revised Probability approximation of no collisions
added 226 characters in body
Dec
5
comment Probability approximation of no collisions
@user822719 Yes. The factor 2 in the denominator comes from $1+2+3+ ... +(t-1)=\frac{t\cdot(t-1)}{2}$.
Dec
5
revised Probability approximation of no collisions
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Dec
5
answered Probability approximation of no collisions