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Mar
20
answered McEliece key size
Mar
20
awarded  Enlightened
Mar
20
awarded  Nice Answer
Mar
19
comment Why is Serpent faster than AES in this benchmark?
@Gael With parallelism I mean that you have the inputs for multiple blocks (with 16 bytes each) available at the same time. In that case you can call a (single threaded) function that takes e.g. 32 blocks and produces 32 encrypted blocks. This function is cheaper for Serpent than encrypting 32 blocks individually. Using Serpent-XTS should be faster than AES-XTS on your current hardware, but once you get a AES-NI capable CPU AES will pull ahead.
Mar
19
comment Why is Serpent faster than AES in this benchmark?
In that case the AES numbers are plausible (16 cycles per byte) compared to ~12 on i3 without AES-NI in the eBACS benchmark.
Mar
19
revised Why is Serpent faster than AES in this benchmark?
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Mar
19
revised Why is Serpent faster than AES in this benchmark?
added 326 characters in body
Mar
19
revised Why is Serpent faster than AES in this benchmark?
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Mar
19
answered Why is Serpent faster than AES in this benchmark?
Mar
19
comment Why is Serpent faster than AES in this benchmark?
What CPU do you have? Intel? AMD? How fast? Which architecture?
Mar
19
comment Does a dynamic accumulator exist yet?
@DrLecter You still need a trusted party who promises to forget the factorization. While you can generate RSA moduli without knowing their factorization they're very big.
Mar
18
comment What is the importance of the $r$ and $c$ values for the Sponge Construction?
C=128 has a security level of 64 bits against certain attacks, but the output size is still unlimited.
Mar
18
comment Elliptic Curves of different forms
If you assume that the weierstrass implementation is safe, you only lose performance. Rigidness is the only property that directly relates to the security of the curve, all the other safety properties are about making it easier to write a fast and secure implementation. For example BouncyCastle C# is neither fast nor secure.
Mar
18
comment Is this a secure (and correct) sign-then-encrypt technique for transferring messages?
RSA is very fast for encryption and signature verification (public key operations) and slow for decryption and signing (private key operations). ECC has decent performance for all operations. If you sum the cost of encryption and decryption, RSA is certainly much slower than than its ECC equivalent (by a factor 10 or so).
Mar
18
comment Is this a secure (and correct) sign-then-encrypt technique for transferring messages?
IMO it's a silly design. 1280 bit RSA sucks for confidentiality but might be good enough for authentication. ECDSA on the other hand is trickier to use than RSA encryption, since it needs good randomness for each signature (unless you use an uncommon deterministic variant). Using EC-DH (256 bit) for key-exchange (and thus encryption) and RSA for signing would be a far better choice. Or just one algorithm for both.
Mar
18
comment Is the term “Elliptic Curve Discrete Logarithm Problem” a misnomer?
Mathematicians don't care how you call the basic operation. We commonly call it addition, but calling it multiplication is just as valid.
Mar
18
comment How do the following new (2013) ECC curves compare in security or efficiency?
The larger the curves the slower (but stronger) they are.
Mar
17
comment Is this an acceptable implementation of ARC4 encryption for my system?
@traxonja If you want authentication and encryption you could consider AES-CCM.
Mar
16
comment Elliptic Curves of different forms
Why do you want to use a montgomery/edwards curve if you then proceed to perform weierstrass form operations on them? To take advantage of montgomery form you need to use differential addition with an appropriate ladder. The whole point of supporting montgomery ladders is that you use them.
Mar
14
awarded  Nice Answer