Cryptography Weekly Newsletter

Cryptography newsletter

Top new questions this week:

Spritz cipher sponge function capacity

Rivest and Shuldt proposed a new sponge like cipher algorithm called Spritz: In this paper they say that the strength of the cipher is related to the ...

sponge sponge-function  
asked by Simon G. 4 votes

Achieving 32-bit verification code with 16-bit CRC?

I am programming an embedded chip that has a hardware 16-bit CRC module. I have to protect some data bytes $d_0,d_1,...,d_{n-1}$ against corruption caused by sudden loss of power; a 32-bit CRC would ...

asked by TonyK 3 votes
answered by fgrieu 1 vote

Finding strong primes

Wikipedia lists the following conditions for a prime to be strong: $p-1$ has large prime factors. That is, $p = a_1 q_1 + 1$ for some integer $a_1$ and large prime $q_1$. $q_1-1$ has large prime ...

prime-numbers safe-prime  
asked by Mints97 3 votes
answered by fgrieu 4 votes

Is this a valid "fix" for deterministic encryption in encrypted databases?

It appears (after doing some light research) that for encrypted databases to be practical enough to be usable, deterministic encryption is required, specifically with regard to the type of encryption ...

database deterministic-encryption  
asked by user3150164 2 votes
answered by pg1989 1 vote

Why isn't CTR mode (counter mode) used more often?

For the CTR mode, the design is good for parallelization, yes, it seems the benchmark of the program downloaded from crypto++ proves that on an Intel I7 CPU. My question is that as most of CPU on ...

encryption modes-of-operation ctr  
asked by qiuhan1989 2 votes
answered by Maarten Bodewes 6 votes

Is there a strong cryptographic reason for GCM's 2^39 - 256 bit limit?

In reading through the original GCM specification (McGrew & Viega '05), the composition of the 128 bit Initialization Vector as a concatenation of a 96b nonce and a 32b unsigned wrapping counter ...

asked by Jeff 2 votes
answered by Ruggero 0 votes

How are the AES inverse S-Boxes calculated?

I would like to know, how to calculate the inverse S-box. I followed this link (with affine transformation first, then multiplicative inverse), but the result is wrong. For example, if I use the value ...

aes s-boxes  
asked by spunky031 2 votes
answered by Richie Frame 2 votes

Greatest hits from previous weeks:

No SHA-1 collision? Yet SHA-1 is broken?

Is there a known pair of distinct bit strings (A,B) such that SHA-1(A) == SHA-1(B)? If the answer is no than how can SHA-1 be considered broken?

hash sha-1 collision-resistance  
asked by Andrew Tomazos 23 votes
answered by CodesInChaos 27 votes

Can you help me understand what a cryptographic "salt" is?

I'm a beginner to cryptography and looking to understand in very simple terms what a cryptographic "salt" is, when I might need to use it, and why I should or should not use it. Can anyone offer me a ...

encryption hash passwords salt password-based-encryption  
asked by Bhavik Ambani 15 votes
answered by MartinSuecia 33 votes

Can you answer these?

Is it possible to perform one-way Diffie-Hellman MITM?

Here's something that is bugging me recently: suppose that me and my friend establish an OTR session and - as a result of that - DH key exchange is performed. My friend verifies my key, but I cannot ...

diffie-hellman key-exchange man-in-the-middle  
asked by d33tah 2 votes

PRGs from OWFs: Implementations?

This is a fairly common topic but I have a specific question given recent developments in theoretical PRGs from one-way function (OWFs). In theory, we have PRGs iff OWFs exist. The first construction ...

asked by epsfooling 1 vote
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