Questions tagged [data-privacy]

Data privacy refers to (cryptographic) methods to prevent the disclosure of sensitive (identifying) information of persons.

Filter by
Sorted by
Tagged with
1
vote
1answer
354 views

Unique, anonymous online authentication

Is there a way to authenticate users online without knowing their real identity yet preventing them from registering twice? If not, what is the least amount of information you would need? If it helps, ...
1
vote
1answer
67 views

Which is more secure PEPP-PT or DP-3T?

Which of these population tracking protocols is better from a cryptography point of view? Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) Decentralized Privacy-Preserving Proximity ...
1
vote
1answer
61 views

Facebook app-scoped identifiers and similar - implementing stateless ID obfuscation

After certain privacy concerns Facebook rolled out a bunch of changes to their APIs, one being "scoping" user identifiers per app. In effect, this means that Alice's canonical facebook user ID is ...
1
vote
1answer
264 views

lookup encrypted text by clear text without decryption

I've implemented vouchers module in my web project where I use it to generate redeem get etc... vouchers. since voucher codes are considered sensitive, I've considered to encrypt them using AES-GCM. ...
1
vote
1answer
133 views

Zero-knowledge voting with hidden weights

Assume a voting with delegates, where each delegate's vote $v_i \in \{-1,1\}$ has a certain weight $w_i$ depending on the number of people who elected the delegate. Is there a way to calculate the ...
1
vote
1answer
2k views

How do I safely anonymize/hash a unique identifier to protect privacy?

I am building a system to collect a unique identifier (MAC addresses from 802.11 probe requests). The system will have several collection points over a large area, submitting to a central database. I ...
1
vote
0answers
49 views

$(\epsilon, \delta)$-differential privacy: main motivation of $\delta$

I am wondering why (not how) we relax $\epsilon$-differential privacy to $(\epsilon, \delta)$-differential privacy. Is the main motivation to reduce the variance of the noise added to the query with a ...
1
vote
0answers
47 views

Content Key Encryption for Multi-User data access

I recently worked out a concept for a use-case, but I'm not sure if my approach is good enough. So I would appreciate feedback and things to look out for, as I'm fairly new to this field. A User can ...
1
vote
0answers
41 views

Is using Fiat-shamir Heuristic safe?

What I'd like to do is to have the Prover store a value x where x remains hidden. From x, I'...
1
vote
0answers
35 views

Calculating the privacy that Renyi ($\epsilon, \delta$) Differential Privacy satisfies

I add differential privacy (DP) to my machine learning models by using PyTorch-DP. PyTorch-DP supplies me with the values: $\epsilon$ and $\delta $. I know that the $\epsilon$ tells us something about ...
1
vote
0answers
51 views

Comparison of end-to-end encryption and TLS

I am writing a comparison paper about security of electronic communication and I want to compare end-to-end encryption and TLS by giving two examples such as Whatsapp and Facebook Messenger. However, ...
1
vote
0answers
63 views

Sigma Protocol with Privacy-preserving Discrete Logarithms?

I've been reading up on Sigma Protocols and Fiat-Shamir Heuristic. There is a small problem I see here that is possibly already solved, but I'd like to know if it has a solution. Peggy wants to prove ...
1
vote
0answers
48 views

Pros/cons of anonymity when messages are encrypted? [closed]

Let's say I'm making an end-to-end encrypted messaging app with the goal of putting "privacy first." The contents of messages are encrypted, but in the current model, it is still visible to the server ...
1
vote
0answers
105 views

Private Set Intersection using a subset of the larger set

Alice has a set $S_A$ with a low cardinality (say ~30k). Bob on the other hand has a set $S_B$ with a much higher cardinality than of Alice's (say ~100M). We're trying to create a reduced ...
1
vote
0answers
150 views

Laplace mechanism from Exponential mechanism in Differential Privacy

In McSherry and Talwar's paper which introduces the exponential mechanism for differential privacy, they say that the Laplace mechanism can be captured by choosing the score function as $q(d,r) = - |f(...
1
vote
1answer
57 views

Filter party-1 strings against party-2 white/black list keeping the lists private

Suppose I have a server and a client. The client has a list of arbitrary strings and the server is supposed to filter this list using white and black lists kept on the server side. It would be nice ...
1
vote
1answer
44 views

what can attackers do between two end hosts

I have one question that I couldn't come up with a nice solution. So let's have this analogy, I have a box full of money and I want to deliver to this my friend. Here if we think of a potential ...
1
vote
0answers
145 views

Leak information (new setting)

This question is similar to Leak Information?, but with new settings. Let $a,b,c,d,e,f$ be selected at random from $\mathbb Z^*_q$. Also, let $r_1,r_2,r_3,z_1,z_2,z_3,p_1,p_2,p_3$ be selected at ...
1
vote
0answers
53 views

Seeking Fast Bloom Filter for Anonymous Address

I had an idea to use something like public message boards to pass secrets anonymously and non-interactively (similar to TV/Movie Trope : http://tvtropes.org/pmwiki/pmwiki.php/Main/PublicSecretMessage )...
1
vote
0answers
127 views

Any algorithm with a pair of master keys and multiple pairs of subkey for a secure key escrow?

Note: This question looks like my other question — Any algorithm with a master key for decrypting private key encrypted messages? — which is perfectly answered by @real-or-random, but this one is ...
1
vote
0answers
88 views

Proving to have sent data, without revealing it

This may be easy, but I'm struggling to find a reasonable solution now. Alice wants to send data to Bob. The data that Alice wants to send has been verified by Carl in some way, even though Carl has ...
1
vote
0answers
59 views

What is the right tool to MPC linear equations system

Given two parties who have private inputes Player 1 - $X_1,...X_n$ Player 2 - $Y_1,...Y_n$ We want to compute a solution to a linear system equation: $f_1(X_1,...X_n,...Y_1,...Y_n) +h_1(X_1,......
1
vote
0answers
130 views

How can user privacy be preserved in certificateless cryptography?

In certificateless cryptography, how can a user preserve his privacy from Key Generation Center? If the KGC becomes malicious, how can the user's privacy be preserved? I read "Privacy-Preserving ...
0
votes
2answers
65 views

What is the implication for differential privacy if $\epsilon = 0$?

In pure differential privacy, the parameter $\epsilon$ represents the desired privacy loss. The smaller the $\epsilon$ is, the more privacy we can obtain. What happens when we want the privacy loss $\...
0
votes
2answers
237 views

Format Preserving Encryption after compression algorithm?

I have large data set which has sensitive information. I want to encrypt different parts of it with different keys. There is also need for compression as data is very large (100s of GB that has to be ...
0
votes
2answers
50 views

privacy enhancing techniques on image data

To give some context: I am looking for a suite of techniques and tools that can theoretically enable me to conduct analysis such as classification on image datasets in a manner in which a naive ...
0
votes
2answers
669 views

Are there any practical use cases for performing homomorphic operations on encrypted Strings?

Does anybody know which practical use cases there are to operate on encrypted strings? Even niche problems that can be solved using homomorphic encryption on strings are interesting to me, but not ...
0
votes
1answer
63 views

Increasing Entropy of Limited Information / ID

Supposed that I get an ID from third party (in this case, Telegram ID which is the range $-2^{31}$ to $2^{31}-1$). I want to store the ID securely and privately into my database by hashing it. I don'...
0
votes
1answer
358 views

Comparing two committed values

Given two commitments on different values, Can a third party compare those two commitments to know which one is the higher value?
0
votes
0answers
16 views

Check correctness of data using only publicly known variables and a server response

A smart contract (a publicly known program) needs to check if the data D is correct (belongs to some fixed set). It is by definition correct if our trusted server checks it and decides it's correct. ...
0
votes
0answers
16 views

The sensitivity in differential privacy with deep learning

In differentially private deep learning, the sensitivity is determined by clipping gradient norm(Abadi's paper). In this paper, when the clipping gradient norm is C, the sensitivity is C. Why the ...
0
votes
0answers
45 views

Advanced Composition (Differential Privacy)

I have a problem understanding the proof of the corollary of Advanced Composition Theorem Advanced Composition: For all $\varepsilon,\delta,\delta' \geq 0$ the class of $('\varepsilon,\delta)$-...
0
votes
1answer
64 views

how many iterations of SHA3 (keccak256) hashing would be required to provide reasonable protection for the following data structure?

((A , B , C) , (D , E , F, G, H)) Where: A is 0x0-0xF, (1 of 16) B is 0x00-0xFF (1 of 256) C is an 8 digit integer D is a one of a list of one hundred words padded to 12 characters E is a one ...
0
votes
0answers
54 views

Encrypting conversation messages stored in database (symmetric encryption)

I have a chatting application like Slack/Discord. In this chat application there chat groups and messages sent by users need to be encrypted in the database. I do not need features like E2E encryption,...
0
votes
1answer
57 views

Adding the same noise to all element of a vector is Differential privacy

In Differential privacy, if we add a $N$-dimension private vector with $N$-dimension Laplace or Gauss noise, we obtain differential privacy. However, if we only generate a 1-dimension noise to add it ...
0
votes
0answers
38 views

Proving anonymous credential presentation

In a CL-based or CKS-based anonymous credential system, how can a verifier $V$ prove that a credential holder $H$ has presented it a credential that has been issued by an issuer $I$ without ...
0
votes
0answers
42 views

Two parties looking to share data anonymously

I've been struggling to find good info on how to do the following: A(lice) and B(ob) each have a table of data (a and b ...
0
votes
0answers
41 views

Audio Files and Digital Bearer Instruments

Is it possible to combine Audio Files and Public Key Cryptography creating a Digital Bearer Audio File that is in complete control of the owner who would then have the ability to grant access to ...
0
votes
0answers
75 views

Data masking / Data obfuscation for string int float and date , preserving order and exact matches

I've to mask data into some different value but to keep their property such as order an exact match (substring is yet impossible) What's the state of the art in data masking? I've some data on which ...
0
votes
1answer
138 views

Zero knowledge proof in smart parking managment systems

I read this paper on protecting user privacy in smart parking management system. It talks about using zero knowledge proofs to protect privacy but I am not certain how they do it. My assumption is ...
-1
votes
1answer
102 views

Is this construction a secure MAC?

Let $F:\{ 0,1 \}^n \times \{ 0,1 \}^ n \rightarrow Z^*_q $ is a PRF, and $H:\{ 0,1 \}^{2n} \rightarrow \{ 0,1\}^n$ is a secure hash function. Is the following construction $\Pi=(Gen,Mac,Vrfy)$ is a ...
-2
votes
1answer
145 views

How Zero Knowledge Proof enables Privacy By Design [closed]

How does Zero Knowledge Proof (ZKP) enable Privacy By Design?

1
2