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
vote
1answer
253 views

Can Add and Multiply On Cipher Text achieve all operations?

A Fully homomorphic encryption scheme needs to support an evaluate function that can do add and multiply operations on cipher text. Can we do all kinds of complex operations on cipher text like ...
1
vote
2answers
217 views

homomorphic encryption special case of multi party computation?

I read that Fully Homomorphic Encryption schemes are special case of Secure MPC in page no 3. Especially , generalization of two party computation problems stated by Yao But is there any additional ...
1
vote
1answer
258 views

Are there any multiparty homomorphic encryption schemes?

Are there any multiparty homomorphic encryption schemes ? Most of the literature is about two party schemes . Is there any generalization made for n party ?
1
vote
1answer
112 views

Homomorphic crypto allowing anonymous yes/no votes?

I'd need a crypto system allowing online yes/no votes but without revealing who voted what. Is a "partial" homomorphic crypto system what I'm after? Would, for example, Damgard-Jurik work in my case? ...
1
vote
1answer
136 views

Connections between Instance Hiding and Fully Homomorphic Encryption

Another approach taken by researchers for carrying out computations over encrypted data is Instance Hiding. In brief, If a user wants to outsource the computation of a function for a particular input ...
1
vote
2answers
300 views

Store hashed email and compare hash values

I have a number of different systems sending me email addresses, but I don't actually need the underlying email, just a hash of the email address. I know I can compare hash values to find matches ...
1
vote
1answer
160 views

fully homomorphic encryption (FHE)

Please, I would like to find some hints or solution to my following problem, I would appreciate your assistance to walk with me throughout the solution Given fully homomorphic encryption (FHE) ...
1
vote
1answer
84 views

How can I do minus on plaintexts in the Paillier cryptosystem?

We have $E(a)$, $E(b)$ encrypted under the same Paillier key. As we all know, we can get $E(a+b)$ by calculating $E(a)*E(b)$. But can we get $E(a-b)$, by calculating $E(a)/E(b)$? I tried to ...
1
vote
1answer
135 views

Which homomorphic encryption scheme has the same size of plaintext space and ciphertext space?

I want to pre-compute the result for all possible ciphertext of a homomorphic encryption. Is it acheivable? Is there a fully homomorphic encryption scheme that has the same size of plaintext space ...
1
vote
1answer
73 views

How do you prevent the risk of damage to the security of Fully Homomorphic Encryption?

In this paper on pg. 1248 in the "preprocessing phase" section the authors say: In the preprocessing phase, the parties run a (standard) MPC to collectively generate a key pair (pk,sk) for the ...
1
vote
3answers
650 views

What goals is homomorphic encryption aiming to solve?

As I understand from this article about homomorphic encryption, it mainly aims to enhance the security of cloud computing. We should be able to encrypt data and send it to the cloud. After it is send, ...
1
vote
3answers
387 views

Can we construct fully homomorphic encryption scheme based on non-circuit approach?

At present, all FHE scheme are be constructed based on circuit approach. Can we construct fully homomorphic encryption scheme based on non-circuit approach? Is Polly cracker non-circuit approach ?
1
vote
0answers
53 views

Exponentiation with fully homomorphic encryption [duplicate]

I have often heard that because a fully homomorphic encryption scheme allows for both additions and multiplications on encrypted data, most other operations can be simulated. I don't understand how ...
1
vote
0answers
54 views

Obliviously computing the Least common multiple of two poylnomials

Consider I have two polynomials $f_1$ and $f_2$ of the same degree. I want to secure them (using any kind of encryption except FHE) and outsource them to an untrusted server. I want him to compute the ...
1
vote
0answers
70 views

RSA or Paillier is good? [closed]

I want to implement file storage in cloud using homomorphic encryption. I want to use paillier encryption. Can you suggest the drawback of RSA to store and retrieving the files. Then only i can use ...
1
vote
1answer
53 views

Proving correctness of a decryption of a homomorphically summed ciphertext?

I would like to take some additively homomorphic cryptosystem - don't care much which one for now - and encrypt a series of numbers with it. I would then like to (in public) take these numbers, add ...
1
vote
0answers
75 views

Privacy-Preserving Protocols and Proofs of Security

While dabbling in privacy-preserving protocols (mainly using Semi-Homomorphic Encryption) and coming up with miscellaneous ideas for comparison tests or other similar primitives, based on obfuscation ...
1
vote
0answers
46 views

ElGamal Homomorphic Encryption Formula Question [duplicate]

With Pubic Key $(G, q, g, h)$ where $G$ is a group, $q$ prime, $g$ a generator of $G$, Am I right in thinking that: $$\mathrm{Enc}(m;r) := (g^r, h^r \cdot g^m)$$
1
vote
0answers
101 views

What scheme will allow merging and splitting the result of a function?

I am wondering if it's possible to have a scheme as follows. Here is the scenario: we have a set of objects (e.g. strings) {O1, O2, ..., On} we have a set of users {U1, U2, ..., Um} each user asks ...
1
vote
0answers
46 views

Encrypted Functions with Fully Homomorphic Encryption [duplicate]

While Fully Homomorphic Encryption schemes facilitate carrying out computations over encrypted data, can the function that has to be evaluated be encrypted too ? For example, if i have some programs ...
0
votes
2answers
143 views

Cryptographical formalization of computational privacy

Yesteryears problems of communication privacy has been well defined in cryptography through Asymmetric cryptography. Due to rise in Cloud computational model , computational heavy tasks are being ...
0
votes
1answer
48 views

When homomorphic encryption goes wrong?

Consider I have two ciphertext $c_1$ and $c_2$ encrypted using RSA encryption. By definition if I multiply them I'd get $c_1.c_2 \ modN$. My question is what would happen if $c_1.c_2 >N$. Can we ...
0
votes
1answer
50 views

How bad would it be to reuse the random blinding factor in a scheme like Paillier?

A secure and somewhat fast way to "re-encrypt" (refresh? anonymise?) a Paillier ciphertext, $c$, is to multiply it by an exponentiated random value: $c \gets c \cdot r^n \mod n^2$ (with $r \in ...
0
votes
1answer
43 views

can you suggest any applicayion for implementing threshold homomorphic encryption cryptosystem(Paillier cryptosystem) [closed]

I want to implement one project in multi party homomorphic encryption using paillier. Can you suggest any application for implementation.
0
votes
1answer
123 views

Secure Multiparty Sum in malicious model using threshold encryption

Suppose $n$ actors each hold a plaintext $p_i$. We wish to find $\sum p_i$, without leaking any information about individual $p_i$. Any actor (or any link in the network) could be controlled by an ...
0
votes
2answers
169 views

Homomorphic Encryption: how does the equality test on ciphertexts work?

Let's suppose we have a asymmetric crypto-system $H$ which is homomorphic with respect to some function $F$. Alice encrypts a message $m$ with her private key $e$ in the crypto-system $H$ and ...
0
votes
1answer
128 views

Homomorphic Encryption Notation Question

What does the following notation mean in a homomorphic encryption scheme? ENC(x;r) What does x and ...
0
votes
1answer
105 views

practical use of homomorphic encryption

Are RSA and Elgamal partially homomorphic techniques? which one is better if one want to use it for practical purpose? and is there some FHE technique which can be used practically?
0
votes
1answer
127 views

Noise bound in FHE over the integers

I'm studying the paper Fully Homomorphic Encryption over the Integers by Marten van Dijk, Craig Gentry, Shai Halevi and Vinod Vaikuntanathan. I have questions about the proof of Lemma A.1. In page ...
0
votes
0answers
32 views

BGV FHE scheme parameters

In their paper presenting the BGV scheme, the authors mentioned in section 4.4 that, for the RLWE variant, the ring degree d, dimension n and noise distribution do not necessarily vary with the ...
0
votes
0answers
37 views

Mistakes in Jarecki-Liu use of Camenish-Shoup encryption?

I am implementing a protocol that uses Jarecki-Liu OPRF, which itself uses a simplification of Camenish-Shoup Encryption. Description of the way they do Camenish-Shoup is in section 2.3 of ...
0
votes
0answers
62 views

Don't Understand these Parameters

I don't understand section 3 of the paper Fully Homomorphic Encryption over the Integers. How can one calculate these paramters and make these equations in pictures into code?
0
votes
0answers
32 views

Perform general computation using a crypto algorithm as a building block

I have a somewhat special question. In our software we use a existing dongle which got cracked by our customers. The protection offered by the dongle isn't very sophisticated. For the moment I can't ...
0
votes
0answers
46 views

Partial Homomorphic Schemes with padding

As mentioned in wikipedia there are many Partial Homomorphic Encryption(PHE) scheme like RSA, Elgamal, Pailler etc. But out of them only unpadded RSA scheme seems to be partial(multiplicative) ...
-1
votes
1answer
200 views

Homomorphic encryption based on XOR

Consider the values $a$ and $b$ are encrypted as $c_1=(a \oplus D)$ and $c_2=(b \oplus D)$. My question is: can we derive $b+a$ from any combination of $c_1$ and $c_2$? Note: I admit that the ...
-1
votes
1answer
138 views

Which areas in CS will be (or have been) most affected by fully homomorphic cryptography? [closed]

I'm in the middle of planning a 5000ish word essay on fully homomorphic cryptography, the current practical implementations and their limitations. Which areas of CS as a subject have been (or will ...
-2
votes
2answers
101 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
96 views

simple encryption scheme turns out to be “somewhat homomorphic”

In the paper Fully Homomorphic Encryption over the Integers in the introduction: How do I calculate $r$ and $q$ of this equation in the picture? $r \approx 2^{\sqrt{\eta}}$ and $q \approx ...
-3
votes
1answer
78 views

can anyone give the java code to encrypt files using paillier [closed]

I want to implement encryption on personal files using paillier encryption. Is it possible to encrypt files using this encryption..