Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [functional-encryption]

Functional encryption is a type of public-key encryption, where the party that has access to a secret key can learn a function from that key, which is used to encrypt and decrypt messages.

4
votes
3answers
152 views

Homomorphic & Functional encryption: Mapping unencrypted outputs to encrypted outputs using existing data

Let's assume I have datapiece A which, after being put through a model or neural network, has a known output X in the unencrypted space. When I move datapiece A into an encrypted space, and put it ...
3
votes
0answers
53 views

Functional encryption for inner products from DDH

I have been reading this paper by Abdalla, et al. But there's something I don't get about the security proof (Theorem 3.2) for the basic IP scheme from DDH--how are they simulating the mpk's using $g^...
0
votes
0answers
43 views

Funtional encryption to Attribute based encryption

I have been reading through the literature in Functional encryption and Attribute based encryption. Undoubtedly, FE is a stronger notion than ABE and FE implies ABE. But, to my knowledge till now I ...
-1
votes
1answer
44 views

Is there any kind of function that has a property like this?

First of all, sorry for any horrible formatting, I have to type this in from my phone. I know (or, at least, I think) that no currently used cryptographically secure hash functions exist with this ...
1
vote
1answer
71 views

derive child keys from a private key

My problem is the following: I have an organization with many members. When someone from the outside communicates with this organization, I want any member to be able to decrypt the communication. ...
0
votes
0answers
18 views

Security definition for functional encryption

Suppose there is a server that announces that it performs FE of functionality F on message m and suppose there is a user that wants to know F(m), though m cannot be revealed as it is private. Is there ...
-1
votes
1answer
68 views

Correctness and how to define it using probability

I would like to understand why some definitions of correctness allow a negligible failure probability. i.e. the probability that decryption reverses encryption is 1 minus a negligibly small amount. I ...
3
votes
1answer
56 views

Enabling Oblivious Access Control via Function Encryption

Abstract With Functional Encryption, would access control between two parties be possible without revealing the entirety of one party's policy to the other? E.g. such that a server would be incapable ...
1
vote
0answers
252 views

Functional signatures with ECDSA Verifier

Functional signatures use some master key to create a functional signature key. The functional key can be used to sign messages, but only if the message is accepted by some predicate function. For ...
0
votes
3answers
125 views

How to encrypt a message such when a certain condition is met it can be decrypted?

Assume, there is a certificate authority whose public key: $pk$, is known. Also, the certificate $c$ is known, but not the signed certificate. I want to encrypt a message: $m$, such that whoever has ...
4
votes
2answers
177 views

Special-purpose witness encryption without multilinear maps

In Witness Encryption and its Applications Garg et al describe "witness encryption" which allows one to encrypt some specified data to a NP problem, such that another party can decrypt iff they ...
12
votes
4answers
3k views

What is indistinguishability Obfuscation?

I've been studying functional encryption. Recently read that a Multi input functional encryption (MIFE) implies indistinguishability Obfuscation. Can someone please brief me: what is ...
2
votes
2answers
200 views

Indistinguishability Obfuscation : What are it's consequences on crypto? [closed]

I was reading about the construction of IO using MIFE and compact FE . I am just curious to know what are the consequences if there exists an IO.
13
votes
1answer
647 views

What is complexity leveraging

Complexity leveraging is a technique that is generally used to prove adaptive security of a selectively secure scheme. Eg: We can prove adaptive security of Yao's garbling scheme using complexity ...
1
vote
0answers
26 views

Weakly Sublinear Compact FE from Succinct FE and XiO

I'm confused about a problem these days and I decided to seek an answer here. The question is about the section 4.1 of the paper LPST16. Let me recall the weakly sublinear compact FE scheme $\textrm{...
1
vote
1answer
73 views

Is there any functional encryption scheme whose key generation circuit is in NC1?

To my best of knowledge, I have kown there exists randomized encoding scheme whose encoding circuit is in $NC^1$, fully homomorphic encryption scheme whose decryption circuit is in $NC^1$, and ...
0
votes
0answers
50 views

Is a good idea to generate a public key from a secret key using a functional encryption scheme?

FE - functional encryption PK - public key I want to design a PK cryptosystem that has a unique PK for each encryptor. Namely, the encryptor submits a unique value (or an attribute) to the private ...
1
vote
0answers
93 views

What functional encryption scheme can be used to compute a linear function?

I am looking for a functional encryption scheme that can compute a linear function. I do not need to work with attributes. All I want is to compute the result of a function $y = a*x+b$, where $x$ is ...
0
votes
0answers
120 views

How does ABE decryption works? [duplicate]

I am trying to understand how Attribute Base Encryption (ABE) works. So, after downloading libfenc library from here, I built the source code on Ubuntu 12.04 without any error. Afterward, I tried to ...
6
votes
1answer
422 views

What is matrix branching program?

Recently I am reading something about order-revealing encryption (by Boneh at al. in EuroCrypt 2015) and encountered "matrix branching programming". It seems like it took me forever to understand this....
2
votes
2answers
1k views

Simple example to describe Bilinear mapping

Notation : $\mathbb{G}$ is an additive group and $\mathbb{G}_T$ is multiplicative group of prime order $q$. Bilinear mapping $e: \mathbb{G} \times \mathbb{G} \rightarrow \mathbb{G}_T$ has to satisfy ...
8
votes
0answers
264 views

What are the current limitations (and capabilities) of Functional Encryption used for access control?

I'm trying to make my way in Functional Encryption used for access control. I read a lot of papers such as "How to Run Turing Machines on Encrypted Data", "Functional Encryption: New Perspectives and ...
1
vote
1answer
479 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) ...
4
votes
1answer
115 views

Can we run a probabilistic function on ciphertext with Functional Encryption (or Attribute Based Encryption)?

In the definition of functional encryption ($FE$): $FE.Setup(1^k)$ takes as input the security parameter $1^k$ and outputs a master public key $fmpk$ and a master secret key $fmsk$. $FE.KeyGen(fmsk, ...
5
votes
1answer
447 views

“Practical” operations supported by functional encryption?

I'm curious about what operations have been developed into functional encryption schemes. What I mean by that is: what operations can be performed over encrypted ciphertexts? Obviously homomorphic ...
3
votes
1answer
1k views

Functional Encryption (for Non Experts)

I recently stumbled across "How to Run Turing Machines on Encrypted Data". Given that it's now possible to run turing machines on encrypted data, what open problems remain in the realm of Functional ...
0
votes
1answer
7k views

Are there any Truth Table to Boolean expression converters? [closed]

I am working on Bent functions that are of interest in cryptography. I developed an algorithm that construct such functions. However, I need some tools to calculate boolean expression from the truth ...
15
votes
2answers
2k views

Practical consequences of using functional encryption for software obfuscation

I came across this article, which describes a method, developed by UCLA CS professor Amit Sahai et al, for using functional encryption in order to achieve software obfuscation. The paper that the ...
2
votes
2answers
268 views

Is Functional Encryption about Access Control over encrypted data alone?

Informally, In functional encryption system , a decryption key allows a user to learn a function of the encrypted data. But all i see is that the function acts as an access control over the data. ...
4
votes
2answers
3k views

What are monotonic and non monotonic access structures in ABE ?

While reading Attribute Based Encryption Schemes, I did not quite understand what a monotonic access structure or non monotonic access structures are. Is there a popular explanation of those terms ? ...
8
votes
4answers
2k views

Is there any semantic difference between predicate encryption and functional encryption?

Predicate encryption(PE) arrived as a descendant of attribute based encryption. Attribute based encryption allows the encryptor to embody a policy to the ciphertext (Ciphertext-Policy based encryption)...