1
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0answers
23 views

What is the exact algorithm and functions of the 4 way handshake?

I have to make a detailed diagram of the 4 way handshake and formulas for its functions so I need to know the exact process behind it. Like precisely what functions are used in it? I have been trying ...
1
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0answers
70 views

Feasible attacks on ECRSA cryptosystem

In ECRSA cryptosystem, I want to know the feasible attacks. For illustrations we have two prime $p$ and $q$ such that $p \equiv 2 \pmod 3$, $q \equiv 2 \pmod 3$ and generate key pair as follows: $$n = ...
1
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0answers
28 views

Hash function notations and their corresponding existing cryptographic hash algorithm

I am implementing Role-based access control by referencing the paper Enforcing Role-Based Access Control for Secure Data Storage in the Cloud. In page 6, they have mentioned to choose hash functions $...
1
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0answers
40 views

Build a hash function that returns a digest in $\mathbb{Z}_{N}^{\ast}$

I want to know if there is a way to build a Hash Function in a such way? $\mathcal{H}:{\left\{ {0,1} \right\}^*} \to \mathbb{Z}_{N}^{\ast}$, $N=pq$ and where $p,q$ are primes.
1
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0answers
66 views

Homomorphic encryption over finite fields

I'm curious on the following question: let $\mathbb{F}_{2^n}$ be a finite field which is an extension of $\mathbb{F}_2$ with order of $n$, is there an encoding scheme $e:=\mathbb{F}_{2^n}\rightarrow \...
1
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0answers
51 views

How can I obtain the raw decimal value of an RSA key's modulus?

So maybe I'm thinking about this too hard, or maybe I'm missing a piece of information. We'll use Google for this example. Say I wanted to obtain the modulus of Google's current public key. Well I ...
1
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0answers
32 views

What is the right tool to MPC linear equations system

Given two parties who have private inputes Player 1 - $X_1,...X_n$ Player 2 - $Y_1,...Y_n$ We want to compute a solution to a linear system equation: $f_1(X_1,...X_n,...Y_1,...Y_n) +h_1(X_1,......
1
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0answers
21 views

How share size is reduced in robust secret sharing?

THIS IS ROBUST SECRET SHARING SCHEME The dealer $\mathcal{D}$ wants to share a secret among the participants $\{P_1, P_2, \ldots, P_n\}$, where at most $t$ participants are malicious and $t<n/2$. ...
1
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0answers
43 views

Countering Cryptographic Attacks

By reading Camellia Design and Analysis document following is my understanding about few cryptographic attacks from designer point of view. Differential and Linear Crypt-analysis. Number of Active ...
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0answers
95 views

How to generate 1000 prime number of 1024-bit with much less time?

I am generating thousand prime number of 1024 bit each. But it takes lots of time. My procedure is as follows. Generate prime number using ...
1
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0answers
25 views

To utilize asymmetric cryptography in symmetric manner - demand-of-security-definition?

Cryptography can largely be divided into two classes: asymmetric and symmetric. Like homomorphic encryption now greatly restricted in the asymmetric cryptography, the difference of asymmetric and ...
1
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0answers
86 views

Encrypted comms between devices on LAN

I'm trying to encrypt a protocol that shares data between devices on a local area network (i.e.no connection to the internet). I don't want to use predefined keys because they're too easy to read from ...
1
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0answers
38 views

Additive homomorphic encryption over small fields

Are there encryption schemes that are additively homomorphic with respect to small fields such as $\mathbb{F}_{2^4}$ or $\mathbb{F}_{2^8}$?
1
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0answers
19 views

How to calculate how many trials I need to guess the plain text if a simple P-Box is used to make the cipher text

If I have 64 bit as input for a straight box that use a transposition process to encipher the plain text and the given 64 bits contains 60 bits as (1s), then how many trial I should do?
1
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0answers
65 views

Software Security Impossible in Non-Trusted Hardware?

Fundamentally it is impossible to protect software if you can't trust the execution platform (e.g. using a TPM), so what is the point of software security then? With vendors claim that their white-...
1
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0answers
47 views

Safe MAC proof check

Let $(Mac, Vrfy)$ be a safe defined $MAC$ over $(K,M,T)$ where $ M = \{0,1\}^n$ and $T = \{0,1\}^{128}$. Is the following $MAC$ safe? Show your proof. $Mac'(k,m) = Mac(k, m)$ $Vrfy'(k,m,t) = \{Vrfy(...
1
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0answers
10 views

Why the light contrast of a set $\mathcal{E}$ of VCRG produced by an encryption scheme for a binary image B is defined as follows

In the paper “Image encryption by multiple random grids”, Shyong Jian Shyu, 42(7):1582-1596,· July 2009, the light contrast of a set $\mathcal{E}$ of VCRG produced by an encryption scheme for a binary ...
1
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0answers
39 views

Key Distribution Center Key Protocol Analysis

As shown in the image, why is Circle 1 to be B and Circle 2 to be A? Why is not the opposite, that is, Circle 1 to be A and Circle 2 to be B? like this picture From my understanding, Notation B in ...
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0answers
34 views

hash function for elliptic curve co-ordinates

Is there any hash function which takes the co-ordinates of an elliptic curve $E_p(a,b)$ as input and gives an integer value i.e. $h(.) : \{(x,y) \in E_p(a,b)\} \rightarrow \mathbb{Z}$
1
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0answers
39 views

Issue Factorization Quadratic Sieve

Good evening, I'm about to write my own quadratic sieve implementation in C using GMP library for large numbers. I'm facing an issue while attempting to do the last factorization step for the number: ...
1
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0answers
27 views

How to approach to solve cipher text with fixed length key (which is repeating)?

I took a project to solve for lecture. In my project for a given cipher text(length 2031), I have a key (Picture of example is given.) which I do not know the length of it. So I started to try to find ...
1
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0answers
25 views

MAC-then-encrypt: Using one-time-MAC with randomized CTR

The Coursera cryptography 1 course says: If you want to use MAC-then-encrypt mode then you should either use randomized-CTR or randomized-CBC. And if you use randomized-CTR then one-time-MAC ...
1
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0answers
61 views

How to normalize data of a generic HTTP request for the purpose of signing

I am working on PowerAuth 2.0, a solution for counter-based signing of HTTP requests (for the purpose of mobile banking). One of the tasks that I solved somehow but I am still not happy with the ...
1
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0answers
42 views

How to break a Quagmire 3 cipher?

What would be a good way to go about attacking a Quagmire 3 cipher? I understand that it is polyalphabetic with a key and an indicator. I have started by taking the cipher text, taking every n-th ...
1
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0answers
47 views

DTLS 1.2 Finished message

I am implementing DTLS 1.2 and using ECDHE_RSA_AES_128_GCM_SHA256 cipher suit. Below is my client finished message Can anyone explain this message? How many bytes for verify data? Is there ...
1
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0answers
135 views

Simulation-Based Proof: When a Secret Key is Involved

Assume we have a protocol in which a party receives an encrypted random polynomial. The polynomial is encrypted using his public key. We want to construct a simulator for this party (so this party ...
1
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0answers
53 views

Encrypting/Decrypting using RSA and AES; standards?

I'm looking for a standard way of encrypting and signing a message using RSA and AES. I understand that in pseudo code the actions taking place are like this: Alice's actions for sending a secret, ...
1
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0answers
39 views

Does a password that's cracked someone's account increase the chances of cracking someone else's account?

For every find in password that cracks someone's account, does that particular password have a higher probability of cracking someone else's account more than a brute force dictionary choice? How ...
1
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0answers
29 views

Algorithm to rotate values in a predefined manner

I will start with an example. Some beacon like estimote Beacons use something called secure ID. The ID transmitted by the beacon change every 10 minutes autonomously without contacting the server. ...
1
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0answers
59 views

Is 3 rounds more secure than 2 in this simplified DES?

Consider the following simplification of DES: a plaintext message block of $2n$ bits of length is divided into two blocks of length $n$ (left half $L_0$ and right half $L_1$). In other words, the ...
1
vote
0answers
70 views

How to use OpenSSL command line utility to encrypt data with encrypted key from public key?

I may not be asking the right question. I am fairly new to data encryption. I am currently being sent encrypted data that's stored as follows: [ [keysize] [key encrypted with public key] [ivsize] [...
1
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0answers
62 views

What functional encryption scheme can be used to compute a linear function?

I am looking for a functional encryption scheme that can compute a linear function. I do not need to work with attributes. All I want is to compute the result of a function $y = a*x+b$, where $x$ is ...
1
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0answers
60 views

Does using a verifiable secret sharing scheme ensure robustness of a protocol if it is secure under the semi-honest adversarial model

Consider a protocol $\pi$ which uses a linear secret sharing scheme like that of Shamir secret sharing. Further assume that the protocol $\pi$ has been proven to be secure (correctness and privacy) ...
1
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0answers
67 views

Calculating the discrete logarithm

I'm given a prime number $p = 1217$ I'm also given the following equations: $$ 40 \equiv \log2 \pmod{64} \\ 63 \equiv \log3 \pmod{64} \\ 13 \equiv \log5 \pmod{64} \\ 13 \equiv \log2 \pmod{19} \\ 10 \...
1
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0answers
48 views

Why is Siphash-128 considered “experimental”?

Why is Siphash-128 still considered "experimental"? What does this mean?
1
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0answers
20 views

How do I prove the tracing part in a ring signature model?

I have a question about the article “efficient and multi-level privacy-preserving communication protocol for VANET” by H. Xiong et al. I need the ID of malicious vehicle, but I could not prove how I ...
1
vote
0answers
23 views

Can you have partial cryptographic obfuscation (without a trusted setup)?

Cryptographic Obfuscation is a powerful cryptographic technique. My question is, can you do it partially? Instead of obfuscating an algorithm completely, you can have an algorithm with a couple of ...
1
vote
0answers
49 views

Given a public-key encryption and signature scheme, define a new primitive

I'm new to cryptography and am currently working on the following question: Say you are given a public-key encryption scheme $\Pi_e=(\mathcal{K}_e,\mathcal{E},\mathcal{D})$ and a signature scheme $...
1
vote
0answers
70 views

Format Preserving Encryption FF1 Samples

NIST published methods for Format-Preserving Encryption and there is a link in the document giving examples for FF1 methods. I am confused by the value of R given in the examples. $R$ is the output ...
1
vote
0answers
25 views

Deriving Minimum Description Length of Substitution Key

Given a plaintext: Now is the time for all good men to come to the aid of their country because the quick brown fox jumped over the lazy dog. and a substitution ciphertext: Mpe od yjr yo,r ...
1
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0answers
18 views

Sigma protocol: witness hiding

I am working on an assignment and I am stuck with the last part of proving witness hiding for the protocol. I have previously proved it is witness indistinguishable, and it has q (primer number ...
1
vote
0answers
22 views

Should we use exponent 3 in RSA-OAEP?

As I understand it the proof that RSA-OAEP is secure in the random oracle model is much tighter for exponent 3. Does that mean that exponent 3 should be chosen?
1
vote
0answers
15 views

Why does HS1-SIV allow forgeries when the SIV collides, even when the PMN does not collide?

The HS1-SIV authors claim that forgeries are possible if an SIV collision occurs. However, I do not understand how this is possible unless the PMN collides too. Otherwise, the collision will be in ...
1
vote
0answers
42 views

Is parallel, vectorized NORX nearly as fast as hardware-accelerated AES-GCM?

As I understand it, NORX gets 3.5 CPB in an unoptimized implementation. But NORX can be parallelized. With 4-way SIMD, I would expect about 7/8 CPB performance. This is nearly as good as AES-GCM in ...
1
vote
0answers
39 views

How to encrypt an image with logistic chaotic map?

I need to encrypt color images, using logistic chaotic map. Could you please recommend an algorithm for this? All the articles that I've found on the Internet are completely unclear.
1
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0answers
40 views

AES - Size of T-Boxes and obtaining T-Box values

In article "A high performance ST-Box based unified AES encryption/decryption architecture on FPGA" (http://www.sciencedirect.com/science/article/pii/S0141933115001945) two 32Kb dual-port BRAMs are ...
1
vote
0answers
39 views

Can error correcting codes be used to guess this plaintext?

I pick a finite set of messages, perhaps the set of integers $M = \lbrace n \in \mathbf{Z} \, : \, 0 \leq n\lt10 \rbrace$, which you are then allowed to encode in any way you want (some form of error ...
1
vote
0answers
37 views

How to provide mathematical proof of the security of a stream cipher against known attacks?

Suppose a person has invented a stream cipher and he/she wants to get it published. I have a few questions: In addition to providing detailed description of the algorithm, how would he/she give ...
1
vote
0answers
50 views

Why need mapping to slots to embed bytes in AES-homomorphic encryption?

The encoding of each AES bytes $𝛼_𝑖$ is using CRT(Chinese remainder theorem). It means that there is an aggregate plaintext $H$ such that: $H \mod F_0 =𝛼_0(MappingData[0])$ $H \mod F_1 =𝛼_1(...

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