# Tag Info

Accepted

### How are side-channel attacks executed? What does an attacker need to execute a side channel attack?

Here's a very simple timing side channel attack that you might even see in movies. Suppose you're trying to log in to a computer with a password, and the victim compares your password byte by byte ...
• 48.8k
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### How can I force slow decryption in the browser?

As I indicated in the comments, I believe a non-cryptographic solution may be the best for this task, where instead of attempting to measure "10 minutes" by the average amount of time it ...
• 13.5k

### How can I force slow decryption in the browser?

I don't know about enforcing browser decryption, but here's an old trick for fast encryption and slow decryption if you understand RSA. Generate a 2048-bit RSA modulus $N=pq$ and a random exponent $d$....
• 24.1k
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### How long does it take to crack RSA 1024 with a PC?

RSA-768 took 2000 years of 2.2Ghz single-core Opteron from the year 2009. DJB et al wrote in 2013 (see page 30) (see also: 29C3: FactHacks (EN); slide 87/112; about 10 minutes) that RSA-1024 would ...
• 824

### How are side-channel attacks executed? What does an attacker need to execute a side channel attack?

This is an attempt to an Explain to me like I'm five style answer: Assume you have a bank vault with a mechanical combination lock. Your cipher in this case is "combination lock". At first sight it ...
• 301

### Cryptography elements needed for a story

Though quantum computers fit the requirements, I'm not sure they are the best option. A general purpose quantum computer capable of attacking modern encryption (RSA, AES) would have serious ...
• 11.8k

### Can I change the radio frequency according to my encryption algorithm?

More physical layer security than encryption. Spread spectrum wideband radio using frequency hopping does this. https://en.m.wikipedia.org/wiki/Frequency-hopping_spread_spectrum What is required is a ...
• 22.9k
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### Encryption and decryption with Diffie-Hellman

The purpose of Diffie-Hellman is solely to establish a shared key, $K$. Taken from Wikipedia: Traditionally, secure encrypted communication between two parties required that they first exchange ...
• 1,249

### Are there any cryptographic algorithms, which lets the user apply some modifications on the encoded data, without decoding it?

Can I modify encrypted data without accessing it? if there is an example appreciate it If access means altering the data without decryption as an attacker then the answer is yes for messages without ...
• 49.1k

### What are the smallest possible RSA private and public keys?

Per the definition of RSA in PKCS#1v2.2 In a valid RSA private key, the RSA modulus $n$ is the product of $u$ distinct odd primes $r_i$, $i=1$, $2$, â€¦, $u$, where $u\ge2$. That makes $n=3\cdot5=15$ ...
• 143k

### Are there any cryptographic algorithms, which lets the user apply some modifications on the encoded data, without decoding it?

If (and ONLY if) it was encrypted with a special "homomorphic" encryption scheme, then you can do the operations allowed by that scheme. Those are almost never used in practice currently (...
• 5,836
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### Would creating a custom human language be stronger protection than encrypting a known human language?

$$\texttt{NO}$$ In short; $$\text{We are living in a world where that is ruled by Kerckhoffs's principles}$$ The above may not be totally clear as indicated by Maarten in the comments. The We is ...
• 49.1k

### Why does the Bombe not consider the Ringstellung when determining stecker pairs?

I didn't want to delete this question, but it seems like after pondering this for a week I finally understand right when I seek help online. When the ring setting and the rotor position all increase ...
• 301
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### Advantages and possible usages of encryption schemes with probabilistic decryption

Since when decrypting we always want to get the correct message back, there's no reason why we would want to make this ambiguous. It would have no security advantage (if the adversary can guess with ...
Accepted

### Does file size significantly affect brute-force time?

AES is a block cipher and typically operates on large plaintext data by dividing it into blocks of fixed size (128-bits in the case of AES) and processing these blocks individually. Similarly ...
• 24.1k

### Is this toy RSA demonstration flawed?

You wouldn't be a Dave for presenting RSA, but you would be a Dave for following this description to implement anything, and you risk creating Daves with this presentation. I'm not saying you shouldn'...

### RSA: The algorithm aside, how are we turning a string into an int and vice versa?

Basically there are two steps to this: encode the text to bytes - this generally requires a character encoding such as UTF-8 or Latin encoding; encode the bytes to integer - this is part of the ...
• 93.4k
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### Can the RSA public key be used for both encryption and decryption?

The standard convention in asymmetric cryptography (thus RSA), is that key generation generates a key pair comprising a public key and a private key, and unless otherwise stated the public key is ...
• 143k

### Is an invulnerable code possible (including brute force attack)?

No, If we assume that the mythical computer can brute force the multiple AES encryptions and there are many ciphertexts available which are encrypted under the same key and their corresponding ...
• 49.1k
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### NaCl allows decryption with the same public key as for encryption

Alice and Bob's keys are used to compute a shared key. Both parties compute the same key, which is used both encryption and decryption. This is a traditional, hybrid encryption system. Using only ...
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### What is the exact meaning of the public key cryptosystem properties in New Directions In Cryptography by Diffie and Hellman

Well, it's good that you're trying to learn. However, learning from the original seminal papers does have some issues that you need to be aware of. For one, sometimes the original authors did not ...
• 149k
It would take you a while, but yes. You'd have to print out several tables that calculate things for you like $GF(256)$ field multiplication and inversion, but you could do it. It would be slow and ...