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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0answers
42 views
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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1answer
35 views
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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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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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.
...
2
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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 $...
3
votes
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 ...
2
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1answer
117 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 ...
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76 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 $(\varepsilon,\delta)$-...
2
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0answers
54 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 ...
3
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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 $\Delta(Y,...
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44 views
Is using Fiat-shamir Heuristic safe?
What I'd like to do is to have the Prover store a value x where x remains hidden.
From x, I'...
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0answers
46 views
Calculating the privacy that Renyi ($\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 ...
2
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1answer
105 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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1answer
93 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 ...
2
votes
1answer
74 views
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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2answers
75 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
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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0answers
71 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
76 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 ...
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0answers
39 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 ...
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0answers
54 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, ...
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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 ...
3
votes
2answers
491 views
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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0answers
66 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 ...
3
votes
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 ...
2
votes
0answers
50 views
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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0answers
44 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 ...
3
votes
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 ...
1
vote
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 ...
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0answers
49 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 ...
2
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2answers
1k views
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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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 ...
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0answers
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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0answers
89 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
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2answers
749 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 ...
3
votes
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
153 views
How Zero Knowledge Proof enables Privacy By Design [closed]
How does Zero Knowledge Proof (ZKP) enable Privacy By Design?
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2answers
162 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 ...
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vote
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.
...
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0answers
153 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(...
4
votes
2answers
131 views
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 ...
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 ...
2
votes
0answers
95 views
End-To-End encryption for VoIP teleconference applications and many-to-many lag-sensitive applications
There are various protocols that allow you to have privacy-enhanced chat.
Those can be either 2-party chat such as:
OTR
SIGNAL
or multiparty chat such as:
SIGNAL
(n+1)sec
mpOTR
GOTR (2013 spec and ...
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 ...
5
votes
1answer
716 views
Difference between Īµ-differential privacy and (Īµ, Ī“)-differential privacy
I don't understand the necessity of introducing the additive term Ī“ in the differential privacy definition. Moreover, reading different papers and blogs they say that because of the Ī“ term the ...
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vote
3answers
250 views
Encryption for IOT devices with minimal overhead
I have several IOT devices that transmits nearly 200 bytes of data every 10 seconds. I want to make the data secured but i also want to keep the data size nearly same. Ofcourse for IOT devices ...
2
votes
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
113 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
0answers
28 views
Avoiding multiple use of sIgned identities while not learning anything about them
There is an authority A with an associated public/private key pair (A.priv, A.pub).
A can issue new "identities" by signing data (numbers or bytestrings).
Each number associated with a signature by A ...
