Questions tagged [data-privacy]
Data privacy refers to (cryptographic) methods to prevent the disclosure of sensitive (identifying) information of persons.
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Mechanisms for masking identifying unique IDs with non-identifying unique IDs to protect privacy?
I need to suggest mechanisms for masking unique codes in a database with different unique codes that are not derived from the original unique codes, but are equivalently unique in that they could ...
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I need to try to find an algorithm to decode a set of Excel dates [closed]
I need to try to find an algorithm to decode a set of Excel dates.
A former employee once told me he could encode a date in Excel and no one would ever figure it out, he said "like a needle in a ...
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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 ...
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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 ...
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2answers
104 views
Sensitivity of probability measure in differential privacy
I know that we need some sort of sensitivity(global, local) to calculate noise that needs to be added for differential privacy. The noise is the maximum difference between two neighboring datasets. ...
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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 ...
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1answer
40 views
The sensitivity in differential privacy with deep learning
In differentially private deep learning, the sensitivity is determined by clipping gradient norm (see Abadi et al.'s paper). In this paper, when the clipping gradient norm is $C$, the sensitivity is $...
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1answer
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Differential privacy what does “where the probability is taken over the randomness used by the algorithm” mean?
The definition of differential privacy is as follows:
A randomized mechanism $\mathcal{M}$ is $(\epsilon, \delta)$-differentially private, where $\epsilon \leq 0$ and $\delta \leq 0$, if for any ...
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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 ...
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2answers
152 views
Differential privacy noise that scales with $L_p$-sensitivity with $p>2$?
It is well-known that to make the result of a $\mathbb{R}^d$-valued query $(\varepsilon,\delta)$-differentially private, you can add noise to it. If you add Laplace noise, you need to scale the noise ...
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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 $(\varepsilon,\delta)$-...
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1answer
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$(\epsilon, \delta)$-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 ...
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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.
...
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1answer
78 views
Laplace Inequality
I am trying to prove that if $r_i \sim Lap(0,1/\varepsilon)$ where $\varepsilon >0$ then:
$$Pr[r_i \geq 1+r^*] \geq e^{-\varepsilon}Pr[r_i \geq r^{*}]$$.
I know that for $r*>0$ it satisfies ...
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2answers
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Interpretation of advanced composition theorem of differential privacy
In "The Algorithmic Foundations of Differential Privacy" book, Advanced Decomposition Theorem (Thm 3.20) is stated as follows:
For all "$\epsilon, \delta, \delta' \geq 0$, the class of
...
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1answer
62 views
Lemma KL-Divergence (Differential Privacy)
I am studying differential privacy and I got stuck again in proof of a lemma. Which is:
$D_{\infty}^\delta(Y||Z) \leq \epsilon$ if and only if there exists a random variable $Y'$ such that $\Delta(Y,...
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Is using Fiat-shamir Heuristic safe?
What I'd like to do is to have the Prover store a value x where x remains hidden.
From x, I'...
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Calculating the privacy that Renyi ($\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 ...
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1answer
107 views
Differential Privacy: What is the 'game' between data holder and adversary?
I have been reading the Differential Privacy (DP) literature for some time to get familiar with it. I feel comfortable with the Math and Stats foundations of it, but I am suffering a bit from the '...
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76 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 $\...
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1answer
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Compute euclidian distance on encrypted data
The scenario is described as following: Let $A$ an user that is transmitting an encrypted (with its own public key $PK_A$) data vector containing its position as $p = Enc(PK_A, [x,y])$ towards a group ...
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1answer
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Differential Privacy: why $\delta$ negligible on the row numbers?
The definition of differential privacy says that an algorithm $M$ is $(\epsilon,\delta)$-differentially private if
$$P(M(x \in D) \in S)\leq e^\epsilon P(M(x \in D')\in S) + \delta$$
where $D,D'$ ...
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1answer
71 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 ...
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73 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,...
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2answers
754 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 ...
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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 ...
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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, ...
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2answers
51 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 ...
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1answer
100 views
Is it possible to derive the recipient's public key from libsodium's crypto_box?
Libsodium has "crypto_box_seal" which according to the documentation is used to "anonymously send messages to a recipient given its public key.", which hides the sender.
But Is it possible for Eve to ...
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1answer
140 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 ...
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1answer
109 views
Why does Īµ-differential privacy protect the subset of 1/Īµ edges in terms of graphs?
In the book The Algorithmic Foundations of Differential Privacy by Cynthia Dwork, Aaron Roth on page 24, databases that take the form of graphs are discussed.
We could on the other hand consider ...
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1answer
103 views
Join Datasets While Protecting Anonymity
I've run into this issue a couple of times in my career. I'll see if I can explain with an example (please ignore the fact that this is implausible in the real-world).
Suppose I sell computers, and I ...
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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 ...
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2answers
92 views
What's the meaning of probabilities in differential privacy formula?
I don't understand what does it mean by "The probability is taken is over the coin tosses of K."
Does it mean, the probability distribution is generated based on exactly same data but only the ...
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1answer
226 views
what does differential privacy (in machine learning) promise or guarantee?
I am recently reading some papers about privacy-preserving machine learning.
Some works incorporate the idea of differential privacy to protect the privacy of the training dataset when the model is ...
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Differential privacy RAPPOR article proof doubts
Recently I've been trying to understand the RAPPOR proof:
\begin{eqnarray*}
P(B' = b' | B = b^*) & = & \left(\frac{1}{2}f\right)^{b'_1}\left(1 - \frac{1}{2}f\right)^{1 - b'_1} \times \ldots \\...
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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 ...
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1answer
66 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 ...
Squeamish Ossifrage
42.5k3 gold badges83 silver badges176 bronze badges
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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 ...
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2answers
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Why the definition in $\epsilon$-differential privacy is multiplicative rather than additiveļ¼
According to its mathematical definition, a random algorithm $M: D\rightarrow R$ satisfies $\epsilon$-differential privacy if the adjacent datasets $x, y \in D$ where $D$ is a whole dataset and ...
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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 ...
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1answer
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Differential privacy on multiple queries ā what is the behavior?
Differential privacy framework still continue to be obscure in the following case:
If I make a set of queries, I can join their output to restore the original data. For this issue we have composition ...
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1answer
625 views
Intuitive explanation of the $\varepsilon$ parameter in differential privacy
I think I have a decent intuitive understanding of what the $\delta$ parameter means in $(\varepsilon,\delta)$-differential privacy: I can explain it to a non-specialist in terms of "what are the ...
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107 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 ...
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Is there a hash tree scheme designed for complex data structures?
I have a JSON object with private data. It has the following (complex!) structure:
...
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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 ...
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1answer
198 views
What are the advantages of mutual private set intersection methods over finding the intersection of hashed lists?
I can understand the usefulness of one-way private set intersection methods. Where Alice and Bob both have listed but only Alice learns the intersection of those lists while Bob learns nothing.
I ...
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1answer
154 views
How Zero Knowledge Proof enables Privacy By Design [closed]
How does Zero Knowledge Proof (ZKP) enable Privacy By Design?
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Cryptographic scheme where a single message cannot be decrypted but if combined with other it can be
i'm wondering if this type of cryptographic scheme does exists. I know about homomorphic encryption but if one has the private key, he can decrypt every single message.
I would like to know if there ...
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1answer
288 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.
...
