All Questions

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File encryption with AES CTR mode

I understand that encrypting files in CTR mode is not perfectly safe, because it potentially leaves the files open for cryptanalysis, if the attacker has access to previous versions of the same files. ...
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DES hardware implementation of substitution lookup table [ ReWorked ]

I'm a crypto enthusiastic and student of cryptography. I'm developing a project with other students titled "A hardware implementation of a DES cryptography for educational purposes", our idea was to ...
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Hash and salt or salt and hash?

People say "hash and salt", but aren't you supposed to salt password the first, and then hash it? So that means its called "salt and hash" right?
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Can one construct OTPs without using XOR?

The typical version of the one-time-pad (OTP) uses XOR to combine a key pad and a message. ($c=m\oplus k$) Now let's assume some other scenarios which have the practical application of blinding. Do ...
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Simple example to describe Bilinear mapping

Notation : $\mathbb{G}$ is an additive group and $\mathbb{G}_T$ is multiplicative group of prime order $q$. Bilinear mapping $e: \mathbb{G} \times \mathbb{G} \rightarrow \mathbb{G}_T$ has to satisfy ...
38 views

What is ε in differential privacy?

In ε-differential privacy, what does the ε refer to? Is it privacy value or the notation used? Can anyone provide an example of differential privacy?
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RSA signature attack check on lowest 16 bytes - Implementation

I am referring to solution given in this question I need help to implement Poncho hint in this comment: As the first question i have an RSA signature of 1024 bit applied on an hash (MD5) of the ...
35 views

Key exchange resilience to DoS attack

I am designing a user registration protocol for a system where I control both clients and servers. The aim is to establish a symmetric key for subsequent authentication, while minimizing the work ...
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can cramer-shoup public key have two difefrent private key?

since I am new to Cramer Shoup algorithm I want to know is it possible to have 2 different private key for a public key due the key pair generation algorithm that Cramer Shoup use? I know that in ...
34 views

Is constructing IND-CCA2 public key encryption schemes particularly easy with the KEM/DEM approach?

After the introduction of McBits, I was interested what security notions are neccessary for IND-CCA2 security of integrated encryption schemes (IES, following the key encapsulation mechanism / data ...
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Reduction to cdp,dl or cdh?

Assuming a randomize encoding scheme that takes as input a secret key $\mathsf{sk} \in \mathbb{Z}_p$ for a large prime number $p$. Then the algorithm outputs $g^{\mathsf{sk}x}, x \in \mathbb{Z}_p^*$. ...
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In NaCl and libsodium, the crypto_scalarmult function implements the operation $Q = kP$ (scalar/point multiplication). There doesn't seem to be a function for point ...
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Execution speed of AES_128 GMAC operation

I have read about the speed performance of AES_128_GCM on specific processors Intel and AMD that support AES New Instruction set. As compared with CMAC and HMAC is it relatively slow for other ...
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Why using AES in ECB (Electronic Code Book) mode a bad idea? [duplicate]

Why using AES in ECB (Electronic Code Book) mode a bad idea? is CTR mode better? Given only these two can be used for parallelization.
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Authenticating small packets

I intend to authenticate small packets of data, between 16 and 256 bytes each. For some of them encryption will also be required. This will be used on small micro controllers, with RAM sizes ranging ...
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Constructing set membership proof for private set

Is it possible to construct a set membership proof to show $\delta \in \Psi$ where $\delta$ is publicly known and $\Psi$ should stay only known to the prover? It seems rather impossible but I would ...
47 views

Can you identify this algorithm? [closed]

We are attempting to integrate our application in to a third party system. To do this we need to pass encrypted passwords in to this system. I have decompiled the assembly and looking at the code it ...
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I'm quite new to the topic and read a bit about poodle and padding oracle. I quite understand the "regular" padding oracle attack, substituting the last byte of block(n-1) to determine the last byte ...
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What is the difference between H(M) and H3(M, s, IDA)? [closed]

What is the difference between H(M) and H3(M, s, IDA)? I am aware of Hash function with a Message and a Key, but there are three parameters in: H3(M, s, IDA). Here M is the message, s is the key, ...
I'm trying to create an algorithm to find the public exponent e given a plain (non-CRT) private key that doesn't include the public exponent, i.e. I've only got $n$ and $d$. A question has already ...