# All Questions

533 views

### Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?

I read the paper Cache-timing attacks on AES (by Daniel J. Bernstein), but I don't seem to understand everything. The author dedicates a long section on how to prevent the OS to interrupt an AES ...
849 views

### AES timing attacks

I'm just interested in cryptography, so please don't expect me to be an expert. ;) I recently read about AES cache timing attacks and found it very interesting. I read the article Cache-timing attacks ...
508 views

### Exhausting the entropy of a hash function

In the case of password storage, consider the following: I have an idea that one can exhaust the entropy of input to the MD5 function by using a 128 bit random value as the password (indeed, any hash ...
235 views

### Message authentication codes construction

I was reading the paper $[1]$ and came across the scheme that I show below. While I understand the scheme well, I don't understand why they prepend a 0 to the block containing $r$ and a 1 to all other ...
400 views

### Safety of DSA key parameters sharing

I'm looking for a solution to use in a context where I need to be able to generate new asymmetric key pairs quickly (using a widely recognized algorithm, and EC-DSA is not applicable). It sounds like ...
2k views

### Constructing RSA private key, given public key

As part of a puzzle I was given an RSA 256-bit public key and an encrypted message. The key itself is very weak, having exponent e = 65537 and modulus N = ...
286 views

### What cipher mode is suitable for independantly decryptable short messages?

I'm building a small VoIP client which transmits encrypted audio data via UDP, and some packet loss is expected, so each packet will need to be decrypted separately even if others in the stream don't ...
158 views

### Is there an advantage to storing keys split between several hashes?

I have a question about the way to store a key or password that was used for encryption, so that the application can check if the user put in the right key for decryption. If I make a mistake, please ...
411 views

### How should one implement a delegated shared trust protocol?

Consider the following (probably naive) scenario. Alice, who is very limited in her knowledge of security in general (clueless about securing a private key for example), wishes to delegate certain ...
836 views

### Does a trace of SSL packets provide a proof of data authenticity?

I'm wondering if it would make sense to record a whole HTTPS session, publish its encryption keys and present it to third parties as a proof that this particular data was sent by a given server ...
224 views

### Why does Schnorr's Digital Signature scheme necessitate two prime numbers?

One of the necessary components to the Schnorr Digital Signature scheme is a pair of prime numbers p and q such that q divides p-1. However, there is never a modular inverse taken of q so why is there ...
169 views

### Does Keccak have an eTCR mode?

On page 7 of NIST's views on SHA-3's security requirements and Evaluation of attacks, I see that, at least at this point, NIST planned on offering SHA-3 having eTCR security (defined on page 3): ...
586 views

### Learning cryptography using a FPGA

I have a FPGA and am curious what cryptographic applications I can use with it. I'm just a hobbyist / security researcher and not a professional cryptographer. Since I'm creating my own curriculum, ...