Questions tagged [database]

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

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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 ...
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27 views

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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28 views

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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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 ...
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60 views

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 ...
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1answer
42 views

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 ...
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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 ...
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1answer
34 views

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 ...
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82 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 $(\varepsilon,\delta)$-...
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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 ...
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1answer
69 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 $\Delta(Y,...
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Calculating the privacy that Renyi ($\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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110 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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189 views

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 ...
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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 ...
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1answer
134 views

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 ...
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E2EE encrypted chat where messages are only readable by participants and admin users

As the title suggests, is there a way to have an E2EE chat between two users, and have them be visible later by an admin user. I know this defeats the point of E2EE, but i want to have the messages ...
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76 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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1answer
119 views

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 ...
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Is the DBMS_CRYPT Oracle package used for the 'plug-in' method of DBMS encryption? Could anyone send links to more information on the method?

I was assigned a research project on the 'plug-in' method which is basically the concept of attaching an encryption package (encryption module) onto the DBMS. When typing in 'plug-in' method into ...
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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 ...
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1answer
58 views

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 ...
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2k 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 ...
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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 ...
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1answer
117 views

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, ...
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230 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 ...
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1answer
297 views

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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207 views

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 ...
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1answer
126 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 ...
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116 views

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 ...
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360 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) ...
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1answer
2k views

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: ...
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97 views

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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Hash function used to find duplicate data, at what point is the risk of a chance match sufficient to switch to a stronger hash or bytewise verifying?

In a lot of data management systems, a hash is used as a kind of data fingerprint, with the intent not to cryptographically defeat an opponent, but to quickly identify duplicate data by seeing if ...
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1answer
809 views

Encrypting data at rest using AES-GCM, where should I store MAC (Message Authentication Code)

I am trying to secure user's profile in database (data at rest). This user's profile is downloaded only after successful authentication at server (based on user's entered password and user name). The ...
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2answers
244 views

Is the statement true in the context of AES-256 encrypted data stored on a hacked server?

I'm writing a document and I am making an important statement in it, which may be used for strategic decision regarding data-management (possibly from never handling sensitive information online to ...
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1answer
1k views

Database and End-to-End Encryption

I'm currently designing a mobile/desktop application to synchronize some messages or notes. I'm searching for a way to secure it and to avoid letting the server be able to read the messages. My goal ...
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1answer
1k views

AES Key Generation based on database guid

I am developing a .NET application spanning multiple servers who should all be able to decrypt data stored in a SQL database. My database is multi-company where each company has its own GUID. since ...
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1answer
3k views

Encrypting user data with their password?

I had an idea once that all of the user data (including the username) could be encrypted with the user's password. Obviously, most sites would store different data, so using the same password and ...
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0answers
391 views

CryptDB data re-encryption and onion layers

From the CryptDB paper , I understoond that the onion layers once decrypted are not re-encrypted. Only columns which are queried infrequently will be re-encrypted to higher onion layers. But if we ...
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1answer
118 views

What are the possible security issues when exporting a plaintext database to a file like this?

Say I have plaintext database with key-value pairs of usernames and passwords. Then I iterate through the database, encrypt the passwords, and write the username and encrypted password pairs to file ...
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1answer
91 views

Secure way to hash a lookup value

I want to securely store a database table that consists of an account ID and a few columns of sensitive data. The data only has value if it can be associated with the account ID. My thinking is to ...
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1answer
430 views

What is the best current way to cryptographically secure databases?

I'm currently working on a proposal for some secure complete system and one of the things currently lacking is the database security. However I don't want to roll my own crypto there and thereby need ...
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1answer
388 views

Backdoorable hash function in password database

I want to use a (preferably established) hash function that is backdoorable in a password database. I want to do so because I need password escrow (being able to get the cleartext back. I want to ...
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3k views

Public key crypto instead of hashing passwords in a database

Suppose I want to keep a client's password database secure (not in plaintext), while still having access to the plaintext password. Now I generates a public/private keypair. Then I send the public ...
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1answer
305 views

Secure method of encrypting data within a database

I'm designing a program which makes queries to a database stored locally which could potentially contain a lot of sensitive information. As such the information must be kept secure as possible from ...
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2answers
709 views

SQL-Like queries in CRYPTDB doesn't work [closed]

I have downloaded and built Cryptdb and it works well. Most of queries on encrypted database run without any issue but, the query with LIKE key word receives an ...
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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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1answer
2k views

Creating unique keys with md5

The project I'm working on requires me to find a way to create a unique key based on data stored in a table. The table in question consists of x columns and y rows. In order to create the key I want ...
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1answer
208 views

How to store and use a Cryptographic Seed in a database [closed]

Companies such as Barclays use cryptographic seeds (for their PINsentry system), RSA do the same for RSA SecurID, but how do they safely secure the seeds in the database. With passwords you just hash ...