# All Questions

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### Homomorphic multiplication by a scalar

Few homomorphic encryption schemes like Paillier , Ring-LWE support homomorphic multiplication operation by a scalar apart from additive homomorphic property. Loosely they could be defined as below ...
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The CAESAR candidate Deoxys is based on a tweakable block cipher that seems to be a strict improvement over AES, in that it is a tweakable cipher resistant to related-key attack. The mode proposed ...
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### Where is the mistake in my RSA by-hand calculation?

Like several previous askers, I seem to have made a mistake in my RSA calculation, but despite going back over it three times, I cannot spot it. I picked 1000003 and 6000011 as my primes, ...
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### Why is DSA falling out of favor?

Windows abandoned DSA rather than extend it to support > 1024 bits; but otherwise I cannot find a reason why DSA would be less desirable. I see in SSH the disabling it by default with a completely ...
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### Cryptographic key with editing safeguard [on hold]

I need to encrypt a number in a file, say 142345. It encrypts to EfsFjs or something else. I need a method that safeguards ...
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### Is AES-256 bit encryption secure against this kind of attack? [duplicate]

Recently I came across this article. http://www.cs.tau.ac.il/~tromer/acoustic/ Could this put all computers at risk for decryption?
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### Can I get successful signature verification with just altering message and signature?

Assuming I can modify a message and also modify the verification signature, and I also have the public-key but not the private-key. Can I create a message that can be verified with a signature that I ...
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### Determining an encryption key when ciphertext and algorithm are known

I would like to know how I can tell that I have successfully performed an exhaustive search attack on an encrypted message. Here are the conditions: key is 40 bit I am aware of the cipher text and ...
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I was looking through different hash methods the other day and was curious as to what the advantages or disadvantages of using separate chaining over linear or quadratic probing. I know that with ...
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### How solid is this method of encryption? [on hold]

Let's say your message is "This is a message." Now translate it into numbers. a=1 b=2 c=3 so on and so forth. Now take those numbers and turn them into three digits based on a randomly generated ...
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### Can someone please decrypt “NUZGIEJX” using Vigenére [on hold]

The key is "FUN". I just want to make sure I am doing it correctly.
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### Deciphering and encrypting using Vigenére square for kids?

Is Vigenére cipher the most basic form of enrypting or is there another simpler way? I'd like to expose my niece to it.
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### Best known attack

I always have listened the term best known attack but I have doubts respect to this term, becase there are several kinds of attacks for example structural attacks, inversion attacks. It is possible to ...
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### Understanding the Hidden Subgroup Problem specific to Integer Factorization

I've been reading about the Hidden Subgroup Problem (HSP), specifically trying to understand how it is related to the integer factorization problem. I've read What exactly is the impact of the hidden ...
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### Question about Cipher Block Chaining(CBC)

I'm studying at the moment the CBC Encryption method,and I was asked in an excercise how many bits would be wrong after decryption if during the transmission 2 bits are interchanged. My guess is that ...
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### mode of operation in cryptography

We need to choose a mode of operation for a Telnet like application where the average message size is between 7 and 1024 bytes. What is the best mode of operation in this case? a. CBC b. CFB c. ...
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### Breaking El Gamal defined over Sn

How can we break EL-GAMAL Encryption defined over Sn the permutation group ? Kindly give the efficient algorithm for it.
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### One time Key Encapsulation Mechanism?

For KEM's, do you only exchange a private key once via the public key encryption and then do all further encryption with this private key, or is a fresh private key sent out with each message? The ...