Cryptosystems which support computation on encrypted data. They might be partially homomorphic (support for one operation such as + or *) or they might be fully homomorphic (any sequence of + and *).

learn more… | top users | synonyms (1)

1
vote
1answer
166 views

Sorting over encrypted data with different symmetric keys

I'm working on a security project. I need to perform a sorting on the lists of encrypted integers and strings. The encryption used is symmetric. The clients send the encrypted data in a list to the ...
0
votes
1answer
30 views

Homomorphic multiplication by a scalar

Few homomorphic encryption schemes like Paillier , Ring-LWE support homomorphic multiplication operation by a scalar apart from additive homomorphic property. Loosely they could be defined as below ...
3
votes
2answers
839 views

Additive ElGamal cryptosystem using a finite field

I'm trying to implement a modified version of the ElGamal cryptosystem as specified by Cramer et al. in "A secure and optimally efficient multi-authority election scheme", which possesses additive ...
1
vote
1answer
42 views

Can we do modulus switching for number theoretic encryption?

Can we do modulus switching for number theoretic encryption such as Paillier or ElGamal?
-1
votes
0answers
27 views

Currently Best Integer not bit FHE [closed]

HElib encrypts and evaluates on bits. Are there any FHE that evaluates on encrypted integers? If there are more than one, which one to choose?
3
votes
2answers
130 views

How to find the value of a vector modulo a basis in lattice-based cryptography

In Gentry's paper on fully homomorphic encryption using ideal lattices, he finds the values of vectors modulo a certain basis. For instance: $\psi \leftarrow \psi' \mod B$ Taken from page 69 of ...
3
votes
0answers
20 views

About BGV Scheme Batching Technique

I am reading BGV12 about BGV homomorphic scheme right now.But I am being stuck to understand Batching technique in this paper. In Pack function (page 32),this paper feeds ciphertext $c_i$ and sk ...
1
vote
1answer
64 views

Analysis of DGHV Security

I want to know how security of DGHV can be breached using oracle and Binary GCD. As I study this paper : Fully Homomorphic Encryption over the Integers But I am not able to understand Section 4.1: ...
1
vote
1answer
42 views

What would be a typical value for the security parameter of the Fully Homomorphic Encryption over the Integers scheme?

The parameters of the Fully Homomorphic Encryption scheme by Dijk et.al are chosen according to the value of the security parameter ${\lambda}$, section 3 of the aforementioned article. What is the ...
4
votes
2answers
98 views

Are there simpler FHE methods than Craig Gentry's original paper?

Craig Gentry's 2010 paper on FHE is very cool, and I'm planning on implementing a basic proof of concept FHE. I was wondering though, are there any simpler methods that have been discovered since ...
7
votes
2answers
168 views

Can the Smart-Vercauteren Homomorphic Encryption be implemented as a practical fully homomorphic encryption scheme?

Smart and Vercauteren proposed a homomorphic encryption scheme (PKC 2010) following Gentry's principles. ​ Though their scheme can achieve fully homomorphism theoretically, they admitted that "for ...
3
votes
0answers
43 views

Quantifying bit security for smart-vercauteren encryption scheme

I am working on project that requires to compare in terms of security between two encryption schemes, one of them is the SV scheme. However, I dont know what are the steps exactly towards quantifying ...
8
votes
1answer
102 views

How do voters verify a Helios (v3) election result?

So from my understanding of verification specification version 3, a Helios election proceeds as follows: A voter retrieves the system's public key to encrypt their vote & submit it. The voter ...
-3
votes
1answer
88 views

How to Perform Computation on AES Encrypted Data

I have this code that successfully performs symmetric encryption using AES algorithm. How can I go about performing computation on it to achieve somewhat homomorphic encryption? ...
3
votes
1answer
68 views

How to prove hardness of approximate-GCD problem?

I am trying to prove the security of my system using the hardness assumption of the approximate-GCD problem using contradiction, i.e. If the attacker is able to break in our scheme, then attacker ...
0
votes
1answer
50 views

Homomorphic Encryption or not

I am a beginner to homomorphic encryption scheme. As far as I think, it is just a kind of concealing real value without using standard encryption algorithms such as AES,DES or RSA. For example , for ...
4
votes
1answer
62 views

Beavers Triple Vs BGW Multiplication on MPC

Typically MPC protocols that are secure against semi-honest adversaries recommend the use of the revised GMW multiplication protocol by Gennaro et al. This is not the case against Active adversaries ...
6
votes
2answers
95 views

Confusion about definition of homomorphic encryption

I am trying to better understand homomorphic encryption, but I feel like I keep getting inconsistent information in the papers that I am reading. One of the papers I am reading says the following: ...
4
votes
1answer
42 views

How does order-preserving encryption work on string?

I have read “How does order-preserving encryption work?”. After that, I completed order-preserving encryption on integer data. Now, I have four questions in this subject: Is it possible to apply ...
0
votes
2answers
97 views

Homomorphic Encryption with Addition and Exponentiation

Is there any homomorphic encryption scheme which supports addition and power over cipher text ? Paillier is close but it supports addition and multiplication with a constant. I am getting an output ...
6
votes
1answer
43 views

Scalability of homomorphic tallying

Whenever I look at online voting schemes, the idea of homomorphic encryption being a key concept, specially in the form of homomorphic tallying, appears to be universally accepted. The accepted answer ...
2
votes
2answers
77 views

How to make the range of modulo $p$ to $[-\frac{p}{2};\frac{p}{2}]$?

I am using NTL (A Library for doing Number Theory) to implement a FHE (Fully Homomorphic Encryption) scheme. In general, the range of modulo p is $[-\frac{p}{2};\frac{p}{2}]$ in FHE scheme. However, ...
3
votes
1answer
108 views

Generating random vector for Full Homomorphic Cryptography

The site below explains that part of doing homomorphic encryption, you need to generate a vector of random numbers that have the property that its dot product against a randomly generated bit vector ...
0
votes
1answer
106 views

Performance of Fully homomorphic encryption VS Paillier encryption in Practice

Consider two schemes both have computation complexity linear to the input size (i.e. number of inputs). One scheme is based on Paillier encryption and the other one is based on fully homomorphic ...
3
votes
1answer
66 views

Why doesn't this operation reveal the voter's message?

I am working my way through this paper. I am trying to figure out the OR zero knowledge proof in figure 2. The prover is verifying that she has correctly voted, and that her input satisfies ...
1
vote
0answers
48 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 ...
1
vote
2answers
127 views

How to identify the difference between two cryptographic schemes in terms of security?

I am currently working on a project, that requires using encryption libraries namely (LibScarab and FHEW). I want to know how can I compare the two schemes in terms of security (I already compared ...
3
votes
0answers
83 views

Finding sum of two encrypted numbers

Let's consider such process: Two emitents emit two (integer) secret numbers independently They encrypt (encode) these number in such a way that no-one (except emitent) can decode these numbers. ...
5
votes
0answers
102 views

Homomorphic system that allows Hamming distance computation?

How can I work out Hamming distance between two binary vectors securely? I would like to know how I can apply homomorphic techniques here.
0
votes
1answer
36 views

dealing with real numbers in Integer Vector Homomorphic Encryption lib

I am using Integer Vector Homomorphic Encryption for the encryption lib. I have to multiply a learning rate of 0.01 (i.e. between 0 and 1) by the encrypted data (vector) but it is not integer. I had ...
4
votes
1answer
94 views

Changing encryption key without revealing the original key

Say that Alice encrypts a $\text{plaintext}$ with $\text{key}_{m}$ and gives the $\text{ciphertext}_m$ to Bob. Alice wants to send several gigabytes of $\text{plaintext}$ to Eve but she is on a mobile ...
0
votes
0answers
28 views

Recryption of ciphertext with a different key

Let's have $P$ some sensitive piece of data and $K_1$a secret value, both known to Alice, but not to Bob. $K_1(P)$ means $P$ encrypted using $K_1$. Alice sends $K_1(P)$ to Bob. Bob keeps the value of ...
1
vote
0answers
59 views

DGHV Bootstrap - How can I recrypt my cipherbit [closed]

I'm implementing this homomorphic crypto-system : http://eprint.iacr.org/2011/440 I'm using SAGE math. I don't get how the bootstrap is done in this scheme, in the appendix A, they say ...
1
vote
0answers
34 views

homomorpic encryption [closed]

I am doing project k-nearest neighbor classification over semantically secure encrypted relational data I have doubt for in smin algorithm in 1)Li ← Wi ∗ Φir′; ri′ ∈R ZN this line it the out put is ...
3
votes
1answer
73 views

Why is this homomorphic encryption correct?

In LTV-FHE, section 3.3.2 Formal description, a ciphertext looks like this $c=hs+2e+b = (2g/f)s+2e+b$, where $h = 2g/f$ is the public key, $f$ is the secret key, $g, s$ and $e$ are chosen randomly, ...
1
vote
0answers
53 views

A topic for my master thesis on post quantum cryptography [closed]

I am a master´s student. I am interested to work on post quantum cryptography. None of my professors are offering any topic this year related to post quantum cryptography. However I have the freedom ...
0
votes
0answers
32 views

Partially homomorphic addition - not all parties present

I often see homomorphic encryption as a solution to a problem where a server wants to know the sum of $n$ users' numbers but can not know each individual users' number plaintexts. My question is: if ...
1
vote
0answers
15 views

For the LTV-FHE scheme, after how many additions should modulus switching be used?

From the LTV-FHE paper I find out that after every multiplication there must be a modulus switch to mitigate the noise in the resulting ciphertext, besides relinearization. But, assuming the ...
2
votes
1answer
94 views

Elliptic curve ElGamal with homomorphic mapping

I am interested in ElGamal due to the fact that you can achieve some degree of homomorphic properties. I became interested in applying ElGamal to elliptic curves, and found this other question with an ...
1
vote
1answer
37 views

How to deal with different setup in Multikey FHE?

The scenario : using a Multikey FHE scheme, let's say LTV-FHE scheme, parties delegate the computation of some function to the mighty cloud. In LTV-FHE scheme the parties generate their keys and ...
-1
votes
1answer
51 views

Should we use modulus switching when dealing with ciphertexts encrypted in different rings?

Having a homomorphic encryption scheme like BGV or LTV-FHE at some point it is possible in the homomorphic evaluation to deal with ciphertexts that are encrypted with respect to different moduli. ...
0
votes
1answer
56 views

Is there an additive homomorphic encryption that supports exponentation

For example say we have two numbers a and b. Now is there any partial homomorphic encryption scheme that allows to compute (a-b)^2 over the ciphertexts of a and b without round trips.
0
votes
0answers
35 views

Encryption of both data and code [duplicate]

Suppose we have 3 parties: Alice possesses invaluable data $x_1, x_2, ...$; Bob can compute some extremely useful function $f$; Carol owns a world's largest data center which have enough resources to ...
3
votes
1answer
106 views

Why gcd(r,(p-1)/r) needs to be 1 in benaloh cryptosystem

I recently discovered the benaloh cryptosystem. I am working with the system as it is discribed in the following link: https://en.wikipedia.org/wiki/Benaloh_cryptosystem However I need some help in ...
3
votes
1answer
86 views

Convert ciphertexts of one encryption scheme to another without decryption

I want to convert ciphertexts of one encryption scheme to another without decrypting them under the first scheme and then encrypting with the second scheme. For example convert OPE encryption to ...
3
votes
2answers
91 views

How can we define division operation by using Fully homomorphic encryption

Last fews months, I'm working with homomorphic encryption. Now I am dealing with some computational problems with integers or real-numbers (like arithmetic mean, standard deviation) where division is ...
6
votes
1answer
97 views

Performing simple arithmetic operations on compressed, and both compressed and encrypted data

We all know it is possible to perform addition and multiplication operations on encrypted data by means of homomorphic encryption methods. My questions are: Is there any cryptosystem that is able to ...
1
vote
0answers
110 views

Example of FHEI scheme?

I am reading this paper Toward Secure Multikeyword Top-k Retrieval over Encrypted Cloud Data. I am trying to work out an example of the FHEI (Fully homomorphic Encryption over Integers) scheme ...
1
vote
2answers
120 views

How can comparision like (>=,==) be done using homomorphic encryption?

Since we know that Homomorphic encryption allow computation on encrypted data. Let two n-bit integers $(x,y)$ are encrypted using some LWE public key cryptography. For example - if $x'= HEnc(x,pk)$ ...
5
votes
0answers
40 views

An MPC protocol from Elgamal is a good solution a homomorphic multiplication?

I want to compute a multiplication between many secret values and then distribute the result to everyone involved. For this, I thought about an MPC protocol built from Threshold Homomorphic Elgamal. ...