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Jul
9
comment Random Number Generator based on AES CTR
Have you considered the CTR_DRBG from csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf ; that's mostly your idea, with the details worked out
Jul
8
answered How is this affine function a pair wise independent permutation?
Jul
8
reviewed No Action Needed What exactly does a key do?
Jul
8
reviewed Leave Open How is the MD2 hash function S-table constructed from Pi?
Jul
7
reviewed Close Where can I begin to study the math behind modern cryptography?
Jul
7
reviewed Approve suggested edit on sha-2 tag wiki
Jul
6
comment Generate Finite Field power of g
Is the question "what is meant by the notation $g^x$"? Or, is the question "how do you do multiplication in the field $GF(16)$"?
Jul
6
reviewed No Action Needed Generate Finite Field power of g
Jul
6
reviewed No Action Needed Type 2 to Type 1 pairing transformation - why not considered?
Jul
5
comment Use ElGamal to solve Diffie-Hellman problem
@CGFoX: well, $z$ is from the ciphertext, and you get to pick that, so of course you can... (I almost mentioned that myself; I'm glad I didn't; it's better that you thought of it)
Jul
4
comment Use ElGamal to solve Diffie-Hellman problem
@CGFoX: stop at $(g^{xy})^{-1} \cdot z$; do you know the value $z$?
Jul
4
answered Cryptool - DES (ECB and CBC ) - double encyption
Jul
4
answered Use ElGamal to solve Diffie-Hellman problem
Jul
3
answered Algorithm for computing square roots in $GF(2^n)$
Jul
3
comment Determine LFSR phase quickly?
@fgrieu: you've got it mostly; however there's one point you missed. When we're switching between $GF(2^k)$ representations, we're not actually changing anything essential in the equation. Instead, a "representation" is just a way of mapping between the elements of the abstract field to bit patterns; and yes, it is fun and easy to convert the bit pattern of one representation into the exact same field element in a different representation. Also, it doesn't matter of the generator is sparse or not; as long as it is primitive, the argument works.
Jul
3
comment Determine LFSR phase quickly?
@fgrieu: the $GF(2^k)$ argument can be used to address the later question; for two different polynomial representations of $GF(2^k)$, there is a linear mapping that preserves the field structure. Hence, we can use that mapping to map from the "hard" representation to the "easy" one, and solve it there. Now, the constant "2" in the hard representation will (probably) map to some other constant; if the easy solution depends on the base 2, we just solve two discrete logs in the easy representation.
Jul
2
answered Determine LFSR phase quickly?
Jul
2
comment After implementing a novel encryption algorithm, how would one go about analyzing its security or get help from others in doing so?
@NoctisSkytower: not off hand. You may find this shocking, but I'm not eager to attack a cipher from a newbee. Have you tried analyzing the cipher yourself? Have you looked into (for example) potential chosen ciphertext attacks (which is an easy place to start)?
Jul
1
reviewed Leave Open generate hash of all handshake messages for verify data (DTLS)
Jul
1
awarded  Nice Question