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Questions tagged [elgamal]

68 questions
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Elgamal BN_exp() operation get stuck

I'm trying to implement Elgamal operations. The common first one is the multiplication between two BIGNUM. The second is the exponentiation of two BIGNUM (e.g. h:=g^x, c_1:=g^y). When I do the BN_exp(), the C program get stuck. Why? Further, any…
CipherX
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ElGamal Signature: Re-Calculate private key with Python

For a project in university I got the following set up: Public key (p, g, h) Two ciphertext-files: (c1, c2) & (c3, c4) Signature files of the above mentioned files: (r1, s1) & (r2, s2) The goal is to recover the plaintexts. I recognized from the…
Mofro
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ElGamal homomorphic multiplication using Bouncy Castle

Long story short: I'm in need of using ElGamal encryption to perform multiplication on encoded numbers. I'm currently using Kotlin with OpenJDK 1.8 and found nice provider for JCE called Bouncy Castle. It provides ElGamal encryption within standard…
w1cked
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Why RSA is said to be faster than ElGamal Encryption?

For RSA, every block of plaintext needs to be exponentiated by the private key: p^e (mod n) For ElGamal, every block of plaintext is multiplied by the secret key s*m (mod n) So I thought ElGamal would be faster than RSA for encryption. However most…
Deus Ex
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Changing 256 byte blocks to number for enryption

I'm working on RSA and ElGamal encryption systems but I'm stuck. I've written those algorithms, I know how it works. How can I change 256 byte chunks of file into number from range [1, 2^2048]? Because I can't pass 256 bytes as an argument with…
ms_heisenbug
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ElGamal signature not verified

I want to implement an ElGamal encryption from this link https://csharp.hotexamples.com/examples/Portable.Licensing.Security.Cryptography.ElGamal/ElGamalKeyStruct/-/php-elgamalkeystruct-class-examples.html This is what I have tried so far and have…
derodevil
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password given for encrypting data

I have done a project in python. Its an Elliptic Curve Cryptography encryption decryption system I used EC ElGamal Algorithm for encryption and decryption. The points on the curve is plotted as shown in the following code: def…
Samseela Subair k
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(ELGamal ) Little step big step procedure maple

Hi I was wondering if anyone can help me with the following question My attempt for part a is below. I don't understand why my procedure isn't working, it runs but then gives no values back when evaluating the procedure for part b. I have used the…
Gibberish
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ElGamal message encryption

I know that i have to encode any message in order to encrypt it using ElGamal cryptosystem. However, i know that's easy when you have a message of a pair of numbers, f.e (5,3). But if you have one like m=2, what should we do to use it as a pair?
Galinho Salonica
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Bouncy Castle El Gamal Keys to byte[] C#

because of the faster decryption i am changing my Code from RSA to ElGamal. So i am using BouncyCastle for the first time now, but i can not figure out hot to convert my keys ElGamalPublicKeyParameters pub_key; ElGamalPrivateKeyParameters…
Alex R.
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what is encrypted file size using elgamal cryptosystem?

What is the elgamal encrypted file size after encrypting, say, a 1mb file of normal text using elliptical curves? I'm getting a 250mb encrypted file size? How much off is it from normal standards?
Chandramouli
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Encrypt/Decrypt image file using ElGamal

I am trying to encrypt and decrypt an image file with ElGamal in C++. It has to use ElGamal encryption. I want to save both the encrypted file and recovered file. I am using Crypto++ libraries for the encryption/decryption part. Here is what I have…
J. R. Ross
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(BouncyCastle Error: min may not be greater than max ) implementation of El-Gamal algorithm using java

I am trying to implement El-Gamal Encryption algorithm in a system. I just learned about the algorithm and looked up the internet for codes to get an idea to implement it. I found the following code on the internet and gives me this weird error: …
Monowar Anjum
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Java Card: can this operations be implemented?

I'm new to Smart Cards and Java Card. I'm planning to implement a variation of the ElGamal key generation algorithm. It's not easy to find information, so is it possible to calculate this steps on a Java Card? Find smallest prime number greater…
P. Sherman
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How to use hash of message for calculating signature in matlab?

I have implemented Elgamal Digital Signature algorithm by the help of wikipedia page. http://en.wikipedia.org/wiki/ElGamal_signature_scheme But now I am confused on how to use hash of a message for calculation? The algo is working fine for m…
Ajay
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