-1
votes
1answer
52 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
88 views

Zero Knowledge Proof for Correctness of the product of additive ElGamal Ciphers [duplicate]

Suppose we use Additive ElGamal defined as follows: Let $(K,E,D)$ be a triple. The key-generator $K$ outputs the description of a finite multiplicative group $G$ of prime order $q$, with three ...
-1
votes
1answer
88 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
2answers
156 views

Digital Signature using symmetric key cryptography

Generally digital signature is a public key cryptography concept.But it needs high overhead. So is there any publication or link available where 'digital signature using symmetric key' has been ...
-1
votes
1answer
115 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
1answer
70 views

Advise key management protocol

Assume that sender and recipient both already have each others public keys(certificates). Sender needs to generate session key to encrypt some data and sends encrypted data to recipient. All offline - ...
-1
votes
0answers
124 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
77 views

Sematically Secure McEliece

I am read the Lemma 2 (pp13) in the paper "Kazukuni Kobara and Hideki Imai: Semantically Secure McEliece Public-Key Cryptosystems –Conversions for McEliece PKC– (PKC 2001)". Related to the question ...
-1
votes
1answer
91 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 ...
-2
votes
3answers
1k 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
660 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
1answer
46 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
267 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
48 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
162 views

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

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
97 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
81 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
300 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
309 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
3answers
120 views

In what industries or more specifically in what companies do cryptographers normally get hired ? How are career opportunities? [closed]

In what industries or more specifically in what companies do cryptographers normally get hired ? How are career opportunities ? Currently I'm majoring in mathematics at a university in Denmark, ...
-2
votes
1answer
88 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
2answers
809 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
94 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
63 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
89 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
324 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
678 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
49 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
63 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
98 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
34 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
314 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
78 views

counting points not on elliptic curve

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 ...
-2
votes
1answer
99 views

what is pairing in cryptography? [closed]

Let $G_1, G_2$ be additive groups and $G_T$ a multiplicative group, all of prime order $p$. Let $P $ in $G_1, Q $ in $G_2$ be generators of $G_1$ and $G_2$ respectively. A pairing is a map: $e:( ...
-2
votes
1answer
200 views

Security of RSA-substitution-RSA

Following on from here, I am unconvinced that encrypting twice with RSA is a waste of time: doesn't it depend on what is placed in-between the two encryptions?. What would happen if a permutation was ...
-2
votes
1answer
326 views

With HMAC, can an attacker recover the key, given many known plaintext/tag pairs?

Given many pairs of $(m, t)$, can the attacker compute the key $k$ satisfying $\text{HMAC}(k,m) = t$? (Assume that $k$ was chosen at random.)
-2
votes
1answer
64 views

construct an election protocol for the following election problem..? [closed]

I am something new to election protocols and I am trying to construct an election protocol for the following problem: Let $A= \lbrace a_{1} , . . . , a_{n} \rbrace $ and $B = \lbrace b_{1} , . . . , ...
-2
votes
1answer
779 views

What are open problems in cryptography? [closed]

I would be starting groundwork for my thesis in cryptography , I would like to know what are current open problems in cryptography, few I know of are Fully Homomorphic Encryption Functional ...
-2
votes
1answer
200 views

How to control the output of a hash function to output to specific data according to similarity?

I do not know if the question lies exactly in that field but i'll give it a try unless rejection. I want to study methods of applying LSH functions to feet in a specific area of digest values. Briefly ...
-2
votes
0answers
75 views

Reference implementation of Threefish? [on hold]

I am looking for a reference implementation (in C) of Threefish. Of course, I downloaded the Skein source code, but since this code is designed for a hash function (Skein), there is only some mentions ...
-2
votes
0answers
11 views

Could remailers achieve their goals under conditions of ubiquitous (total) surveillance? [migrated]

I am not certain but I am afraid that the answer to the question would be negative, if the following arguments couldn't be clearly refuted: A sender of a message has to choose a (first) node of the ...
-2
votes
0answers
52 views

Supersingular and Non-Supersingular Elliptic Curves [on hold]

Which one is more suitable for security concerned problems: supersingular or non-supersingular elliptic curves?
-2
votes
1answer
129 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 ...
-2
votes
0answers
91 views

Symmetric-Key Based authentication [closed]

So i've managed to answer all the other cryptography questions, but I have not come across this exam style question before, and need help.
-2
votes
1answer
75 views

How to implement a Cryptographic Pseudo Random Function

I need three pseudo random functions which all take a seed S (t-bits long). The functions should map from $d$ bits to $d$ bits $d$ bits to $1$ bit $d$ bits to $t$ bits $d$ is $10$ bits $t$ is ...
-2
votes
0answers
1k views

encryption and decryption time for RSA-crt in java? [duplicate]

I try compute execution time for encrypt and decrypt data has 1024 bit = 128 byte in RSA-crt algorithm. I need this results. But I believe this result wrong. because big diffrent between execution ...
-2
votes
1answer
199 views

Cryptography based upon neural networks [closed]

I would like learn about use neural networks in cryptography. Is there any research literature on this subject? What should I do to learn about the subject? I am taking short course in neural ...
-2
votes
0answers
458 views

Fiat-Shamir signature [closed]

I have a question about Fiat-Shamir signature: A hash function is h(w)=w mod 2011 and w1=2623, w2=3269, w3=1938. What is h=? and how to determine k.t bits?
-2
votes
0answers
377 views

Why is there a strong distinction between stream and block ciphers? [duplicate]

If I don't err, in the literature a stream cipher is one in which each plaintext bit is processed individually, commonly via xor-ing with one bit of a random or pseudo-random bit stream, while a block ...
-3
votes
1answer
655 views

finding collision for truncated SHA1 hash output

Suppose we truncate only 40 bits of sha1 hash output.hence it is insecure.how can we find two message as input which gives first 40 bits of hash as same value i.e we have to find collision for first ...

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