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10

Let me begin by saying that if you have a hardware source of randomness, you don't need to be stingy with it. 1) Does modulo affect the quality of randomness, faking in some way the distribution of values? Yes, it does. Or at any rate, it can --- see my answer to (3) below for more details. (I'm assuming by "quality of randomness", you specifically mean ...


6

A cryptographical algorithm can't be immune or not immune to side channel attacks; this is because a side channel attack attacks the implementation and not the actual algorithm. Any algorithm that uses secret data can be implemented in a way that has side channel attacks, and any algorithm can be implemented in a way that may be resistant (the hard-core ...


4

No, you will not be ble to abuse challenges in that way. You may be thinking about e.g. raw RSA, where signing and decryption are mathematically similar. However, this is not possible in FIDO U2F: All the defined signature algorithms use SHA256 on the signed data, meaning that you'd have to brute force search for something that produces the correct ...


3

First, take note of my answer to the question Estimating bits of entropy. A key phrase therein: You'll never be able to look at a bitstream without knowing the distribution and say "there are X bits of entropy here." The ent program doesn't know the distribution of the data it's looking at; instead it performs some statistical tests that any ...


3

Ah ... I see. I am not a C/C++-expert. So the union in injector "projects"ints on bitfield and vice versa. That is, the start of ints and bitfield in memory is the same. Writing on bitfield automatically writes on ints. See http://www.wachtler.de/ck/8_7_struct_union.html (in german). So everything is fine.


3

I'll try to give additional explanation on algebraic number and the link with EC. Let $q=2^{163}$ the finite Field $F_q=GF(q)$, as selected by NIST has some features for doing cryptography. This field has been generated with the irreduccible pentanomial you gave in the table. To understand what the trace of the polynomial is, it corresponds to the ...


2

At one point, most music legally sold digitally was protected by DRM (all iTunes music, for instance). Eventually the labels backed down and started allowing the music to be published DRM-free. So yes the music industry has attempted this, but it encountered all of the fundamental problems with DRM and was abandoned. Crypto fundamentally can't protect you ...


2

The bottom of page 3 of your second link (the specification for LED) seems pretty clear: "Note that for a 64-bit key $K$, all subkeys are equal to $K$, while for a 128-bit key $K$, the subkeys are alternatively equal to the left part $K^1$ and to the right part $K^2$ of $K$." Basically, the input master key is split into a sorted list of nibbles, and ...


2

First, you should not write your own CSPRNG - there are plenty of well vetted ones from which you may pick. Second, your text and your pseudo code do not match (rotate key or rotate the seed). Third, as I understand this algorithm it doesn't even give good randomness properties. For example: Main> let seed = `0x82398eeaf74239 : [64] Main> let key = ...


1

GCM is sometimes called a 1.5 pass AEAD cipher, where the CTR encryption counts for 1 and the GMAC counts for 0.5. So you would indeed expect it to be faster than encryption + CMAC and HMAC with regards to the amount of CPU instructions. That is: as long as the encryption is using AES for both solutions. GCM requires a 128 bit block cipher while CMAC and ...


1

Often people build hardware that contains cryptographic algorithms, and they are worried about what happens if that hardware falls into the hands of an attacker. Historically, there have been several approaches to making it harder for the attacker, often used in some combination: Hardware and cryptographic algorithms specifically chosen or designed to ...


1

I've already replied to the question posted some days before. Montgomery multiplication is another way to perform modular multiplication in the residue system representation. The operation induced is in fact a group morphism. In $GF(p)$, $p$ prime, or in the multiplicative group $\mathbb{Z}/n\mathbb{Z}$, the transformation allows to perform modular ...


1

So, you need to do a two-part work. First, you need to make 2+ hardware sensors of an entropy of a different kind. Use the Geiger tube counter [ http://kripton2035.free.fr/geiger-repositor.html ] , avalanche noise generator [ http://www.cryogenius.com/hardware/rng/ ] and when you'll make an ARM microcontroller act as a USB device - make an AM(NOT FM) radio ...


1

BouncyCastle (for Java) has code that performs the AAD processing anywhere in the stream. It does however require modular exponentiation and additional multiplication. GCM mode officially requires the AAD to be processed before the plaintext, but as stated, there is a way around that. I've asked for an explanation here Len A||C is only required at the end ...


1

Actually, you don't compute the trace of a polynomial per se, but of a finite-field element, which is expressed as a polynomial-like expresssion with $u$ acting as the indeterminate. ($u$, as you are probably aware, is a root of the generating polynomial $p(t)$.) Mathematically, the trace of $u$ is $$\mathrm{Tr}(u) = u + u^2 + u^4 + \cdots + u^{2^{162}}$$ ...


1

I don't know if this can help you, but did you know if in Binary Arithmetic, you have: $f(z)=z^m+r(z)$; then $z^m =f(z)+r(z)$. NB: The addition here represents the bitwise XOR, that you can easily represent in hardware by appropriate gates. Then Let's continue by examining the reduction algorithm you show us: ...



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