Questions tagged [database]

A structured set of data held in a computer, esp. one that is accessible in various ways.

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Row level database encryption scheme

I am developing a row level database encryption scheme. Ideally I would not do this and instead rely on something vetted, but I haven't been able to find such a scheme online. My primary concerns are: ...
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Devising a system that allows for aggregate computations but does not hold the single values

First of all apologies if this is not the right place. I am not very knowledgeable in cryptography but I thought you can at least point me in the right direction of research. The following is a toy ...
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How many bits should change in a password salt?

In https://crypto.stackexchange.com/a/27828/79037, it's indicated that one can "save space" by using something globally-unique, like an application-wide "pepper", together with ...
ManRow's user avatar
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Utility Guarantee of Small Data Base Mechanism in Differential Privacy

I am reading Section 4.1 (An offline algorithm: SmallDB) of The Algorithmic Foundations of Differential Privacy by Dwork and Roth. I am stuck at the proof of Proposition 4.4, which is about the ...
KRWTS's user avatar
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AES-GCM for sensitive database field - good solution?

I have been researching the best encryption to use in a .NET application for managing a sensitive database field (column). This encryption is on top of e.g. AWS at-rest encryption applied to the whole ...
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Does anyone know of how I would authenticate the data my algorithm generates?

I have a pytorch model that generates bond trade pairs that have a high probability of reverting to the mean in a 30 day time period. I want to sell the signals, but I do not want them to be ...
John Shelburne's user avatar
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Derive related universally unique identifier (UUID) from a main UUID

Given a list of base entities (B) with each of them having a universally unique identifier (UUID) of 128 bits. I want to attach to them a list of ≤ 7 related entities (TE, UE, ..., ZE) with each of ...
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How is the Unix / PostgreSQL crypt function a trapdoor function?

I am looking at this in the context of password hashing in PostgreSQL, specifically, the crypt function of the pgcrypto ...
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Is there any way to ensure that a network merge, after a parition, never causes disagreements?

Background: A cryptocurrency, such as Bitcoin, have a global order of all transactions that is guaranteed to be agreed by all participating nodes. With Bitcoin, this is ensured by making the longest ...
caveman's user avatar
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Approximate differential privacy: avoiding composition in vector-queries

Assume we have an $n$-dimensional real-valued function $f$ whose $\ell_1$ sensitivity is equal to $GS(f) = 1$. We can also assume the sensitivity of each dimension is also $\Delta f = 1$. For pure ...
independentvariable's user avatar
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Password encryption in database

I want to store passwords in a database in a way I can reuse them to authenticate users (symmetrical encryption). I read some good information here: https://cheatsheetseries.owasp.org/cheatsheets/...
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Best way to encrypt sensitive data on server with HSM and symmetric keys

I need to store sensitive data (like customer photos) in a SQL database in the most secure way in case of security breaches. The data won't be accessed by the clients, only by internal processes that ...
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Compressing SHA256 to be a viable database id?

Don't know a lot about cryptography, so need some help on this. I would like to use a SHA256 string as a unique id in my database for users, but scaling that would be difficult. Is it possible to ...
0a6c42bb1c2f8058's user avatar
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Risks of Using SHA1 Instead of SHA256 for RSA with OAEP Padding

I'm presently implementing a simple RSA-based encryption as follows in PHP (using openssl_public_encrypt): ...
azoundria's user avatar
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Differential Privacy: Gaussian Mechanism when $\epsilon >1$, Laplace Mechanism when $\epsilon = 0$

In Differential Privacy resources, the limiting cases of $\epsilon, \delta$ are not justified well enough. For example, on Wikipedia, it is said that Gaussian mechanism only works when $\epsilon < ...
independentvariable's user avatar
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Should I protect the salt before storing it in a database or use a pepper (secret salt) instead?

If I protected the salt or used a pepper (secret salt) and an attacker got access to the database he can't do a rainbow table attack on a targeted user (a famous or important person). Should I use a ...
Mohammed Rady's user avatar
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Authentication Fold-In in Oracle Database

The Oracle database has a feature known as "Native Network Encryption". It is a protocol described as a 4-step procedure. Step 1 : Negotiate parameters for following steps Step 2 : Exchange ...
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Securing a local database

I am a member of a sports association and I am developping a simple JavaFX application for managing member's license. This application will be used on a notebook without any connection, it has to be ...
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Is AES/CBC/PKCS5Padding vulnerable if used for store data on a db

Is padding oracle attack applicable to data stored on a DB in AES/CBC/PKCS5Padding? Specifically I would like to be able to use Postgres with pgcrypto https://www.postgresql.org/docs/13/pgcrypto.html#...
Fabio Bonfante's user avatar
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What is $z_b$ in this introduction to Private Information Retrieval?

I was trying to read this introduction to private information retrieval. On page 12 of the document, a scheme for 1-DB private information retrieval is discussed. I was unable to understand one of the ...
Sidharth Ghoshal's user avatar
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Homomorphic encryption in social networks

I want to gain some experience with homomorphic encryption, specifically possible applications in social networks. I am thinking about using a HE library (such as Microsoft SEAL) with a graph database ...
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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 ...
Dinosaur Reporter's user avatar
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Is this method of salting effective?

So this is my first post on this forum, so bear with me if I sound stupid. I am creating my own web application with JavaScript and MongoDB. I am storing all user information in a Mongo table, and ...
cardinalsfan13's user avatar
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Is this a reasonable design for encrypting records in a key/value database?

A while back I designed a protocol for en encrypted key/value service. My main goal was to minimize the value of a breached database by using cryptographic algorithms where a brute-force cracking ...
theory's user avatar
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Crypto scheme to map data to users in a way that is anonymous to database server

I am trying to finish a paper on censorship resistant data-sharing systems in semi-centralized ways. I know the below threat model can be mitigated by using decentralized system, but I am looking for ...
skydanc3r's user avatar
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Is my password database encryption flow secure?

I'm not an expert and I would be very glad if someone could take a look at it and tell if there are any problems with it Things I know/think are problematic using base64 digest + getting the first 32 ...
CodingKiwi's user avatar
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End-to-end photo storage

I've been tasked with developing an app that will need to store photos a user takes securely, and I've been struggling to think up a method to do this. What I was thinking so far is as follows: When ...
George Herbert's user avatar
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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 $(\varepsilon,\delta)$-...
Miguel Gutierrez's user avatar
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How to devise cryptographic system with data-sharing ability and password reset

I originally posted this in the security.stackexchange forums but then I was directed to this one which seems more befitting for my question. I am writing a C# .NET application. For my application the ...
csstudent1418's user avatar
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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 $\Delta(Y,...
Miguel Gutierrez's user avatar
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Calculating the privacy that Renyi ($\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 ...
user80982's user avatar
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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 '...
independentvariable's user avatar
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Can you correct my understanding of Argon2? [closed]

I'm a bit new to the cryptography field (completely new), and could really use your guidance. Please, correct my understanding, as defined by the following statements. The ...
Ideator's user avatar
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Integrity for mixture of encrypted/unencrypted database fields

I have multiple blobs each (symmetrically) encrypted with its own randomly generated key. Now I want to encrypt these blob keys with user keys and store them in a database. A table could have the ...
darkdragon's user avatar
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A multi-target attack on 128-bit ECDSA private keys

I'm thinking about doing this as a project, but I'm not sure how I'm supposed to proceed. So I have an 128-bit ECDSA, which would provide about 128 bits of security (if we do not use special methods ...
Anonymous's user avatar
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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,...
Kaka you's user avatar
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Security of using constant salt when saving encrypted data to database

Let's say that I want to save some encrypted data to a database through a Spring Boot microservice. For that I will be using Spring Security Crypto that, as the documentation says it uses AES256 with ...
Jose Antonio's user avatar
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Prevent everyone except customer to read DB data

We are planning an application that must store sensitive data. Data is coming from other sources, the application will be a "collector" of third party data. We need to encrypt database data so no one ...
Claudio's user avatar
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Is it possible to construct dataset for only another party to consult?

Is it possible to construct a dataset made of some kind of probabilistic encrypted indexes such that anyone can update the information contained in the set but only the one with a secret key could be ...
Afonso Delgado's user avatar
4 votes
2 answers
4k views

End to end encrypted web chat app with stored messages in database

I am working on a web app with an integrated chat. All chats can only occur between two users - not more, not less. I am very concerned with security, so I would like to encrypt all chat messages with ...
KingOfDog's user avatar
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Is it possible to encrypt a user’s email in a zero-knowledge way and still send them emails?

This is kind of hypothetical, but let’s say I have a web app and I want to store a user’s email for sending notifications to. Is there any zero-knowledge way to hide their email from ourselves and ...
aroooo's user avatar
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1 answer
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Frequency Attacks on Encrypted Database

I'm trying to build an encrypted database where we can't trust on the database manager. And since encrypt data in a deterministic way is bad, attackers can recover information doing frequency attacks, ...
Simão Dolores's user avatar
2 votes
2 answers
308 views

Search Over Encrypted Data

I'm doing a research about how to search over encrypted data as the title said. And, I saw cryptDB used a cryptographic scheme from Song et.al's article Practical Techniques for Searches on Encrypted ...
Simão Dolores's user avatar
2 votes
1 answer
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Is an IV useless for encrypting database IDs?

In my scenario I need to build a pseudo-anonimization service: a machine that given a plainID return a chiperID and vice-versa. <...
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How secure is a system that retrieves encrypted private keys from a public database?

The system in question is one with multiple users. Each user has a password associated with their account, and each user owns several public-private keypairs. A user's private keys are encrypted using ...
ExecutionByFork's user avatar
2 votes
1 answer
265 views

Encrypting the relationship between two database tables

I'm not a cryptography expert myself, and know enough to know that I shouldn't design my own crypto schemes, so I thought I'd seek advice here. In an application, let's say we have two database ...
Chiubaka's user avatar
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P2P Website/Database Encryption Process

Sorry if this doesn't fit the guidelines, but I believe it is a conceptual issue that is not opinion-based and can be reasonably answered in a single authoritative answer (I'm also struggling to find ...
thebronsonite's user avatar
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2 answers
431 views

Encrypt login id in database

I am developing a solution where each user is identified with a social security number (SSN). So they log in with their SSN and a password. I would like to encrypt the SSN somehow (client-side) ...
HelloWorld's user avatar
3 votes
1 answer
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Is zero IV with AES-CBC safe if CPA is not possible and indistinguishability is not an issue?

Is using zero IVs with AES-CBC safe, if chosen-plaintext attack (CPA) is not possible and ciphertext indistinguishability is not an issue? Practical example: ...
antak's user avatar
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how to efficiently prove the query result is empty?

Consider a simplified scenario. Suppose an untrusted server holds a set of data $A=\{ a_1,a_2,\cdots,a_n\}$. A client issues a query $b$ to the server and wants to decide if $b\in A$. The server ...
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