Questions tagged [database]
A structured set of data held in a computer, esp. one that is accessible in various ways.
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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
45 views
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
44 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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1answer
93 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
132 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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24 views
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
74 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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22 views
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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56 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
77 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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14 views
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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40 views
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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29 views
Blockcipher operation mode pros/cons when used on a database?
say i have a database with multiple independent entries, which i want to encrypt using a block cipher like AES. Which operation mode would be suited for that purpose?
I assume entries can't be ...
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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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2answers
933 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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0answers
31 views
Is it possible to encrypt a userās email in a zero-knowledge way and still send them emails?
This is kind of hypothetical, but letās say I have a web app and I want to store a userās email for sending notifications to.
Is there any zero-knowledge way to hide their email from ourselves and ...
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1answer
109 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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2answers
205 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
273 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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2answers
159 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
117 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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113 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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2answers
327 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
1k 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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1answer
96 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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2answers
2k views
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
732 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
240 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
945 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
2k 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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385 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
115 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
85 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
420 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
360 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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2answers
2k 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
291 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
703 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
102 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
201 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 ...
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2answers
357 views
Is this a valid “fix” for deterministic encryption in encrypted databases?
It appears (after doing some light research) that for encrypted databases to be practical enough to be usable, deterministic encryption is required, specifically with regard to the type of encryption ...
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2answers
966 views
Database row level encryption scheme
I am wanting to secure some highly sensitive data in a database. This would mean that the data needs to be encrypted and remain secure for 100 years if it were to fall into adversary hands. I also ...
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0answers
216 views
Encrypted database: how to deal with general queries?
My question is quite related to the concept of homomorphic encryption, which is not practical at all nowadays.
In short, I would like to know how to query encrypted databases. Simple queries which ...
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3answers
748 views
Cryptographic data structure: sparse array without membership test
I would like a data structure supporting two operations: $\mathsf{set}(k,v)$ and $\mathsf{get}(k)$, with the following properties:
$k$ can be any number between $0$ and something impressively large, ...
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1answer
168 views
Privacy-Preserving relational databases: checking the existence of a record (or multiple records)
I would like to know if there exists a protocol which performs the following operation in a privacy-preserving fashion:
User $U$ wants to know whether a record is stored in the database. The primary ...
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1answer
982 views
Adi Shamir's secret database of all primes
I was going through these presentation slides (PDF) on Crypto 2013.
It summarizes the paper, Factoring RSA keys from certiļ¬ed smart cards: Coppersmith in the wild.
In the last slide, it was ...
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2answers
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Generate a unique 64 bit numeric database key without collisions at $2^{32}$ birthday threshold?
What is the best way to generate a unique 64 bit numeric database key from a string?
For example: if the string is a URL, you could generate a 64 bit key using SipHash or by truncating a SHA256 hash ...
