-1
votes
0answers
93 views

Calculating periodicity of a pseudo random number generator (Middle-square method) [closed]

Below is a Python code that calculates the periodicity of the middle-square method for a given 4 digit-numbers: ...
-1
votes
1answer
153 views

What does it mean that a protocol realizes “strong mutual authentication”?

What does it mean that a protocol realizes "strong mutual authentication"? And What does it mean that a protocol realizes "weak mutual authentication"? Can you define them formally ? I have found a ...
-1
votes
1answer
117 views

How to benchmark custom crypto with OpenSSL benchmark suite? [closed]

OpenSSL benchmark suite currently tests the speed of algorithms supported by the library like md5 sha1 sha256 sha512. What if we have a custom crypto algorithm "abc" . How do we benchmark its ...
-1
votes
1answer
125 views

Attacking both authenticity and secrecy in authenticated encryption modes

looks like NIST only approved GCM mode for authenticated encryption and other modes don't have any approval or a good implementation available. Is that possible a weakness in $GHASH$ compromise ...
-1
votes
1answer
354 views

Guessing encryption algorithm based on key and ciphertext

Is it possible to tell which encryption algorithm was used, assuming I have a key and a encrypted text? To not complicate the situation let assume we are speaking about symmetric algorithms only. ...
-1
votes
0answers
170 views

Approaches to decoding data of an unknown type [closed]

This is a high level question. One area of computer science that I'm working on getting better at is encoding and decoding data. My background is that of a self-taught web engineer who is trying to ...
-1
votes
1answer
89 views

HMAC-Ripemd-160 in TrueCrypt

I'm wondering if it is still secure. I know TrueCrypt closed its doors but I continue using it because the cryptoaudit didn't find any huge bugs or security issues in TrueCrypt. But I have a bad ...
-1
votes
2answers
156 views

Encryption algorithm designed to be easy to decrypt by machine but impractical to decrypt by hand

I am looking for - or considering the design of a new - encryption algorithm that does not use variable keys, such that it is easy for a computer to encrypt and decrypt any message regardless of its ...
-1
votes
1answer
112 views

Can Diffie-Hellman generate values in a specified range?

Is there any way to generate values only between $0$ and $255$ with the Diffie-Hellman method? I need to create keys for communication algorithms with $32$ and $16$ numbers between that range. The ...
-1
votes
1answer
61 views

Diffie-Hellman on infinite groups

The most common groups to be used as examples for the DH protocol are modular multiplication and elliptic curves. But I've realised that the groups doesn't need to be finite, a suitable infinite group ...
-1
votes
1answer
251 views

How does hash function in Elgamal signature scheme prevent existential forgery attack?

I have heard that hashing the message M prevents an existential forgery attack. I was wondering how.
-2
votes
5answers
215 views

Is symmetric encryption no longer necessary?

Here is it: Symmetric encryption is no longer necessary, because all security services can be implemented with public-key cryptography. Moreover, in public key cryptography the operations for ...
-2
votes
3answers
2k views

How secure is the Vigenère cipher in file encryption if you encrypt the password first?

I created a basic file encryption method, that seems pretty secure to me (based on an answer below, it seems to be an implementation of the Vigenère cipher) , but one of my colleagues claims that it ...
-2
votes
3answers
2k views

How can I find the prime numbers used in RSA?

I got this question in a local hacking event, but I couldn't solve it. Problem Statement ---- Continuing their snooping habit, NSA kept bugging Alice's communication. Resorting to the age old ...
-2
votes
4answers
342 views

Do Brute-Force Attacks and Cryptanalysis refute Kerckhoffs's principle? [closed]

According to Kerckhoffs's principle "A cryptosystem should be secure even if everything about the system, except the key, is public knowledge." Now I want to throw in a provoking formula of mine which ...
-2
votes
2answers
217 views

Is (2^333)-1 a prime number? [closed]

How can I see if $2^{333}-1 $ is a prime number? Does this have to do with Mersenne prime numbers ($2^n-1$) ?? Thank you!
-2
votes
1answer
100 views

How many bits of entropy would I get from 300 coin tosses? [closed]

Bonus question, what is the formula to calculate this?
-2
votes
1answer
59 views

moduli in SSL certificates [closed]

this is normally seen in a typical SSL certificate. For the modulus, I know that it is represented in hexadecimal form, but why is there a semicolon (:) after every group of 2 digits? ...
-2
votes
2answers
311 views

How do I choose the best 3*3 s-boxes?

I've read about 20 papers about the criteria for choosing best $n \times n$ s-boxes. Now, I've got two problems: How to generate $2^{24}$ s-boxes, and how to test them considering the criteria. ...
-2
votes
1answer
56 views

How to write the encrypted message after using RSA

I have created a RSA encryption/decryption program but how do i write out the results after doing a encryption? Right now I have it so that it will just print out the decimal value of one character ...
-2
votes
2answers
284 views

How to decrypt 3DES in ECB mode (using a wordlist)? [closed]

I have some encrypted texts (encrypted with 3DES in ECB mode without salt). My question: How can I decrypt them using a wordlist? (or without one) Example: Encrypted text: ...
-2
votes
2answers
123 views

How to best mix two arbitrary/random n-bit words? [closed]

Given two arbitrary/random $n$-bit words, how could one best mix them to get one $n$-bit word for general crypto usages? I suppose that one should have an adequate measure of goodness of the mix ...
-2
votes
2answers
119 views

What is the difference between homomorphic encryption and homomorphic signature? [closed]

I want to apply homomorphic signature instead of homomorphic encryption in Provable data possession. So I want to know about homomorphic signature and homomorphic encryption.
-2
votes
1answer
400 views

Is my one time pad cipher secure?

This is a program that I made for encrypting text files. It uses a one time pad cipher to encrypt the files, but I do not know if there is any holes in my program that could be a vulnerability. Is my ...
-2
votes
2answers
380 views

How weak/strong is this hand cipher? (updated) [closed]

In simple steps here the system: first write text. hand cipher then divide into groups of three letters: han dci phe r then choose a key consisting of three letters, for example ...
-2
votes
1answer
156 views

Why is 2 the inverse of 10?

I have one question about the ECDSA signature scheme. When Bob wants to send a message to Alice that is to be signed she makes following things (with for example $A = (5,1)$, $d=7$, $q=19$). ...
-2
votes
1answer
95 views

Integers in ECC

Let A be a point on curve with integral coordinates. Does k.A necessarily have integer coordinates? If so than why and if not than how to find A and k such that k.A has integral coordinates.
-2
votes
1answer
295 views

Uniform distribution/randomness of characters in the sha256 hash?

I'm using the sha256 algorithm to generate a number in one of my programming projects. A sha256 hash is calculated from three strings: one the user can edit, one the user can view but not edit and one ...
-2
votes
1answer
114 views

What parts of number theory does the RSA algorithm use?

It is said that the RSA algorithm uses number theory. What parts of number theory does it use? I know it uses modular arithmetic and Euler's totient theorem and function. Is that all?
-2
votes
2answers
1k views

How many possible input files are there who's length can be stored in 63-bits?

I'm trying to calculate how many possible combinations of files there can be using a signed 64-bit file length, but can't seem to find a formula (or I'm using the wrong keywords). For example, the ...
-2
votes
1answer
62 views

How difficult is homomorphic encryption? [closed]

I want to learn more about homomorphic encryption and eventually make a career from it. Currently, I'm thinking to have my bachelor degree in this field. What background should I have for this ? How ...
-2
votes
1answer
86 views

I have a keyword and cipher text but cannot decode it please help! [closed]

coded text: ij gj hnev xudmyx hn igim umif obaxidyw kxzq si the key is JULIET, but i cannot figure out how it is used. Any help would be awesome!
-2
votes
1answer
139 views

Why are we advising PKI if we know that quantum computers will break them? [closed]

DNSSEC, ECDHE, RSA, even SSH and all other important specifications, protocols that we rely on and advise people to use them, they use Public key infrastructure. Question: Why do we still use, ...
-2
votes
1answer
110 views

is there an algorithm to encrypt all the datatypes?

Is there an algorithm or technique to encrypt all the datatypes such as (video , image , text , fax, audio ,file,etc...) -one algorithm encrypt every thing-? also if I try to build such this ...
-2
votes
1answer
70 views

function of crypt called “ICE” [closed]

Using exeinfo, I have identified a function of crypt called ICE. What is it? How can I find ...
-2
votes
1answer
1k views

University for Crypto grad study [closed]

(I thought twice before asking this question and quite reluctant to type as well, but I think this would be helpful). I am an undergrad student and choose theoretical computer science as my major. ...
-2
votes
1answer
608 views

How to calculate cycles per byte [closed]

Sometimes, websites and scientific papers that introduce and/or handle cryptographic algorithms also provide speed-analysis and tables comparing the individual performance of cryptographic ...
-2
votes
1answer
94 views

use the same pad reversed

Suppose I have a random number (eg 625 467 921). I use it once to encrypt a message OTP style, and when I want to use them again, I reverse them (eg to ...
-2
votes
1answer
496 views

Encrypting with private key in Public Key InfraStructure [closed]

In Public key infrastructure, the MD5 of a piece of data is encrypted with the private key of a sender and this encrypted MD5 – along with the data – is again encrypted using an algorithm like AES or ...
-2
votes
1answer
883 views

How to hack the new save encryption on ipad for uplink? [closed]

The new iPad version of Uplink appears to be using some newer saving mechanic than the PC/Mac version. Macs and PCs use the REDSHIRT format, but the iPad appears to instead be using ...
-2
votes
1answer
88 views

OTP - Why not reuse key? EDITED! [duplicate]

EDIT: REUSING KEY IS SECURE! OTP - Reusing key IS SECURE! PROVED! This might sound really dumb but why is it bad/insecure too use the same key twice on One-time-pad? Question: Why and how does using ...
-2
votes
1answer
66 views

Hashes and Ciphers [closed]

So I'm brand new to cryptography, I'm confused on a few fundamental issues, and my normal avenues of research aren't bearing any fruit. I'm hoping someone can describe the relationship between ...
-2
votes
1answer
104 views

Question about the security of Substitution-Permutation Network

In general, we execute key-mixing, substitution and permutation sequentially in a single round in a n-round SPN, but if we execute n-round key-mixing firstly, n-round substitution secondly and n-round ...
-2
votes
1answer
84 views

How Proof all Subgroup point of prime order elliptic curve have prime order [#G=#E]? [closed]

anyone knows any reference that proof it ? Please Help .
-2
votes
1answer
87 views

Which causes longer “break” time (in general)?

In general (if possible to determine) which would make an output harder to turn into plain text with a computer? Extreme Length (minor complexity change) Extreme algorithmic complexity (minor length ...
-2
votes
1answer
204 views

How to find out the method used to encrypt [closed]

How to find out the method used to encrypt the string 123456 which results in the value: 6g9SkDLIKa8l2VhafFnHvg==?
-2
votes
2answers
123 views

Python KDF - Master Key and Derivatives

The encrypted file can be opened by following combinations (either any 2 DK, or 1 MK): DK1 + DK2 DK1 + DK3 DK2 + DK3 DK1 + DK2 + DK3 MK Any heads-up with Python ...
-2
votes
1answer
38 views

Finding if exponent share is present in dlog instance [closed]

Let $g$ be a group generator of prime order $q$. Suppose we are given two elements $g^y$ and $x_1$. Can we find out if $y=x_1+x_2$ for some $x_2$? Thanks
-2
votes
1answer
929 views

How to Mathematically Prove the Bilinear Pairing Properties [closed]

I am currently working on Bilinear Pairing.To start my work i need to find the mathematically prove of three properties of bilinear pairing. Let $ G_{1} $ and $ G_{T} $be a cyclic multiplicative ...
-2
votes
1answer
89 views

counting points not on elliptic curve [closed]

Given an curve with equation $y^2=x^3+ax+b$, I want to find the number of pairs $(a,b)\in \mathbb{F}_p \times \mathbb{F_p}$ NOT on the curve. How do I do it? I have an intuition that it is $p$, but ...

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