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Sep
24
reviewed Needs Improvement Is SRP post-quantum secure?
Sep
24
reviewed Satisfactory MAC using a modified CBC mode of operation
Sep
24
comment Problem understanding the construction of block cipher distinguishers
There is no known distinguisher for 2DES that works with less than $2^{56}$ time. I would suggest you start learning with something a tad simpler; how about you start looking for a distinguisher that works against a 2-round version of DES?
Sep
24
reviewed Leave Open simple encryption scheme turns out to be “somewhat homomorphic”
Sep
24
awarded  Custodian
Sep
24
reviewed Satisfactory Elliptic Curve Cryptography
Sep
23
answered Is this modified Schnorr signature scheme secure?
Sep
23
comment Is this modified Schnorr signature scheme secure?
In your modified version, how is $r_v$ used? What prevents a forger from just outputting $e = H(M)$ and $s$ being something arbitrary?
Sep
23
reviewed Close Using modulus in one time pad?
Sep
23
reviewed Close Encryption with data loss protection
Sep
23
reviewed Close Key management for military GPS receivers
Sep
23
comment Fully Homomorphic Encryption over the Integers - perform an operation on an encrypted data
@RickyDemer: cool!
Sep
23
comment Fully Homomorphic Encryption over the Integers - perform an operation on an encrypted data
@RickyDemer: with FHE, it is assumed that we can take any value, and generate an encrypted form of it with the public key. I assumed that as part of my demonstration; if those aren't available, the problem could include a fixed encryption of -1.
Sep
23
revised Fully Homomorphic Encryption over the Integers - perform an operation on an encrypted data
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Sep
23
answered Fully Homomorphic Encryption over the Integers - perform an operation on an encrypted data
Sep
23
comment Generation of N bit prime numbers -> what is the actual range?
@facuq: it's not really "key space" in the sense of, say, AES; the way you attack RSA isn't pick a prime and see if it's a factor of the modulus. Instead, you attempt to factor the modulus using, say, Number Field Sieve, and that 's more difficult with larger modulii. On the other hand, that's not really why we insist on modulii of precisely $n$ bits and not $n-1$; that's more definitional; we have defined $n$ bit modulii to be a certain size; and so one one-bit smaller doesn't meet the definition.
Sep
22
revised Generation of N bit prime numbers -> what is the actual range?
added 33 characters in body
Sep
22
answered Generation of N bit prime numbers -> what is the actual range?
Sep
22
comment Using modulus in one time pad?
@GuutBoy: actually, the group doesn't need to be cyclic; given $d$ and $C$, that there is a unique $k$ s.t. $C=d+k$ is a property of all groups, cyclic or not. As for why the group needs to be finite, well, for groups of size $\aleph_0$, you can't select a random element equiprobably, and for groups of size $\aleph_1$ and larger, well, you run into issues that you can't express almost all the members within a finite number of bits.
Sep
22
comment Using modulus in one time pad?
@zof: it is there in order to make the +/- an operation over a finite group; OTP needs to be performed over a finite group (or, at least, a finite latin square) in order to be secure.