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Feb
25
comment Multiple private keys for single public key
I suspect you need to think more about the security goals (and nongoals) of the system. The cluster head sends a message; who must be able to read the message (e.g. the intended recipient)? Who must not be able to read the message (e.g. random third parties)? Who don't you care whether they can or cannot (e.g. the cluster head itself)? Also, this is an ad hoc network; how do nodes join the cluster? Is there some sort of introduction protocol (where keys can be exchanged)? Depending on the answers, a purely symmetric system may be the Right Thing.
Feb
24
reviewed Looks OK Hill Cipher the point of a known plaintext attack question
Feb
24
reviewed Leave Open Hill Cipher the point of a known plaintext attack question
Feb
23
revised In a additive group is it hard to calculate $bg$ given $ag, g, abg$
added 180 characters in body
Feb
23
answered In a additive group is it hard to calculate $bg$ given $ag, g, abg$
Feb
22
comment Simple message authentication code
@MaartenBodewes: yes, it is a Carter-Wegman MAC that works like this.
Feb
21
awarded  random-number-generator
Feb
20
revised Hash “Preimage by product” resistance
added 878 characters in body
Feb
20
revised Hash “Preimage by product” resistance
Updated answer
Feb
20
revised Hash “Preimage by product” resistance
added 167 characters in body
Feb
20
revised Hash “Preimage by product” resistance
added 69 characters in body
Feb
20
answered Hash “Preimage by product” resistance
Feb
20
comment How to find generator $g$ in a cyclic group?
@LRM: you misunderstood the pronoun (and I fixed the answer to be clearer); compute $h^2$, and if this is not 1, then $h^2$ is your generator (not $h$ -- I used "it's", and it wasn't clear which that referred to). Then, we needn't bother to check if $(h^2)^q = 1$, as that's $h^{2q} = h^{p-1}$, and Fermat's Little Theorem says that'll be 1.
Feb
20
revised How to find generator $g$ in a cyclic group?
added 20 characters in body
Feb
20
reviewed Approve Find a polynomial time algorithm for the following problem
Feb
20
reviewed No Action Needed LUKS multiple key slots - what's the intuition?
Feb
20
reviewed No Action Needed How does double-encryption work with a client server model
Feb
20
revised Complexity of attacks on affine cipher
added 88 characters in body
Feb
19
answered Complexity of attacks on affine cipher
Feb
19
comment What is the polynomial to use in the Massey-Omura cryptosystem?
@Melab: What is $(x+1) \times (x+1)$ (doing arithmetic in $GF(2)$)?