Cryptography Weekly Newsletter

Cryptography newsletter

Top new questions this week:

The effect of truncated hash on entropy

Suppose i have a 128 bits random binary string (128 bits of entropy), then i hash it using SHA-256, then i take the first 128 bits of the output hash. Does the taken bit string still have (almost) 128 ...

hash entropy sha-256  
asked by user40602 5 votes
answered by fgrieu 4 votes

Can machine learning analyze random number generator?

I'm studying for random number generators(RNG) and I saw about machine learning a few days ago. So I searched analysis of RNG using machine learning. But I couldn't find such fields. Are there such ...

cryptanalysis random-number-generator  
asked by Tylor Yoo 4 votes
answered by kaepora 1 vote

Is this a valid scheme to authenticate through a 'human-readable' certificate?

Let's say Alice wants to talk securely to Bob over the internet, and Eve is not only eavesdropping, but has managed to get into a MITM position. In this scheme Alice and Bob exchange $n$ (example $n ...

asked by orlp 2 votes
answered by tylo 1 vote

During electronic voting, how does one hide the choice from Voting device?

Assume the following: I want to cast a vote during an election through an electronic voting system. For our system we make the assumption that the device one uses to cast the vote is potentially ...

anonymity voting  
asked by WeGi 2 votes

Can Poly1305-AES be used with AES-256?

I'm reading through Bernstein's The Poly1305-AES message-authentication code. The MAC is predicated on 16-byte block ciphers like AES and produces 16-byte authentication tags. However, Bernstein does ...

aes poly1305  
asked by jww 2 votes
answered by fgrieu 3 votes

Stacked LFSR - why not used?

New to cryptographic, weak in math. I have designed a PRG which consist of 33 LFSR's, each 32 bits wide. I use one of the LFSR's as "selector", using the 5 LSB from this register to select one of ...

encryption cryptanalysis  
asked by H. Circlebeach 2 votes
answered by kodlu 1 vote

Practical brute-force attack on 128 bit encryption

In brute-force attack calculations cryptographers say we should assume an attacker will find the key after $2^{(n/2)}$ tries. If n=128, then n/2=64. We know that this is practical (A 64 bit key is ...

encryption brute-force-attack birthday-attack  
asked by user40602 2 votes
answered by Maarten Bodewes 13 votes

Greatest hits from previous weeks:

Simple example for CP-ABE (Ciphertext policy attribute-based encryption)

I'm currently working on Ciphertext Policy Attribute-Based Encryption (CP-ABE). So far I'm only using it with a basic understanding how it actually works. Now I want to understand it a bit better, but ...

pairings arithmetic attribute-based-encry  
asked by Baertierchen 1 vote
answered by Ekris 2 votes

How big an RSA key is considered secure today?

I think 1024 bit RSA keys were considered secure ~5 years ago, but I assume that's not true anymore. Can 2048 or 4096 keys still be relied upon, or have we gained too much computing power in the ...

public-key rsa key-size factorization  
asked by Inaimathi 36 votes
answered by fgrieu 50 votes
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