Questions tagged [security]
Questions about matters of computer, software and communication security, that is how to protect systems against attacks.
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What would happen SHA-256 collision were to be found?
As far as I and this wikipedia page know, there are no collisions (2 inputs with the same output) found in SHA-256 (yet).
what would happen if a collision were to be found,
1. would it be easier to ...
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Is this a zero knowledge proof algorithm (security)
Suppose we have a website and you log in the website with a username and a password.During registration your computer downloads a file containing a random 32 digit number.Now when you try to log in , ...
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How exactly does stale data appear in temporal buffer in Downfall attack?
I've read Downfall paper. In the university, I've had an introductory course on computer organization and operating systems. We also studied Spectre and Meltdown attacks there. I understood the ...
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What is the definition of security of universal hashing
As a cryptographic primitive, universal hashing should have somewhat a criterion on its security. How is its (computational) security defined? Or, in other words, what "breaks" a universal ...
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Do passwords need a max length?
I understand that password storage generally uses hashing for security due to it being irreversible and that the stored hash is just compared to the hash of the password inputed by a user attempting ...
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If the data that I input for locality sensitive hashing is sensitive, should its resulting hash also be considered sensitive?
Is it correct to assume that if the input that I hash is sensitive, that I should also consider the locality-sensitive hash generated for that input to be sensitive? I presume that, if an attacker has ...
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Can we extend DDC to three rounds and get more information?
During diverse double-compiling, they say that it is proof that either all the compilers are subverted, or none of them, but they cannot say which one is subverted. In my studies of the technique I ...
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How to resolv this NAT problem?
I am taking my first network class and I came across a question I just cant wrap my head around.
We have an external machine that has a public IP address from using NAT, the external machine want to ...
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Interactive ZKP of possession of a signed message
Suppose Alice has a verifiable (message, signature) pair from Cedric, who would not cooperate and routinely uses an algo (ecdsa, eddsa, rsa, or insert yours here) to sign messages.
Alice wants to ...
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Is booting only a part of OS possible?
I am reading the paper HyperEnclave. I have a few questions about the OS in general.
Is is safe to assume that attackers cannot mount physical attacks during boot process of the OS?
Can we assume ...
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Is it possible to decrypt a string given part of the original string
Suppose I have an encrypted string of bytes. "T37mQkZosCsrcbqf/rvSWbd67qH3sXMggKdVd8fzMdg="
Suppose I know that somewhere in the original plain text string I know there is a string of ...
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Comparing source code and compiled code for ("topological") equivalence
Assume that I have a program Login.c that I have compiled with cc and generated the executable ...
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Why do we rely on computers in critical fields?
I assume that computers make many mistakes (like errors, bugs, glitches, etc.), which can be observed from the amount of questions asked everyday on different communities (like Stack Overflow) showing ...
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How does PBFT tolerate Byzantine Leaders?
It is said that PBFT (or Practical Byzantine Fault Tolerance consensus) is Byzantine fault tolerant (unlike Paxos or Raft that are only Crash fault tolerant.)
Based on this answer : LINK , in PBFT &...
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Why are computers so fundamentally insecure?
This really isn't a complicated question to ask but it is one to answer...
From the very fundamentals of binary code why are computers and similarly, computer language, just so insecure?
Should we ...
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How MAC (Mandatory Access Control) model prevents trojan horse attacks?
I've heard that the MAC Model prevents Trojans to charm files on the system.
How is it possible? Can somebody show any example that MAC model protects us against it?
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Non-repudiation of customer data
For our web application we are maintaining some data, pertaining to our subscribers, on our server. Some of this data is sensitive and we would like to implement some "security measures" ...
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Do modern computers prevent instructions being executed by audio? If so, how?
Most know that early phones and modems, and still, fax machines, sent information through the use of tones. This got me thinking - could audio be a viable vector for executing instructions by a bad ...
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Sharing a requested secret number not knowing which
Alice has a list of secret numbers. Alice wants to give Bob the opportunity to choose one of her secret numbers, and then Alice has to share that specific secret number, but in such a way that Alice ...
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Could an application capture and log a user's actions on another 3rd party software. If yes, how?
Could an application be built such that it could track a user's actions on a particular software and log them?
For example, could an application track a user's actions on MS Word, noting down when the ...
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Having trouble understanding blatantly non-private definition because of Little-o notation
I was pretty confident that I understand asymptotic notation until now. However, I am having a hard time understanding some basic definition that use asymptotic notation, specially little-o.
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How large is the seed in an encryption algorithm such as stream cipher?
The stream cipher is an encryption algorithm that was designed to approximate an idealized cipher, known as the One-Time Pad. It's crucial for a stream cipher to remain secure is to have a ...
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Why did the concept of "write-protecting" not carry over from floppy disks to USB memsticks and especially external USB HDDs? [closed]
Many times, I've wished to plug in my backup hard disks into my PC without the risk of any of the data being deleted, overwritten, or modified in any manner. Purely for "inspection" and ...
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How to get IAB category for 1M websites
I am writing a publication about websites privacy. Quite a standard for such works [e.g., 1, 2] is to summarize categories of websites in the study, to either prove that the study is not biased, or ...
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Does the host operating system know the content of your messages in a messaging applications?
Let's say you are using a messaging application (Microsoft Team, Skype, Telegram,..) on an operating system (Windows, MacOS, Linux). Does the OS know what you are sending or receiving? If yes, how? ...
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Non-Interactive Zero Knowledge Proofs: zk-snarks and zk-stark
I read up on an abstract example of ZKPs (the cave and the door), but I'm trying to understand NIZKs (specifically zk-snarks and zk-stark). All the examples I can find online seem to have some ...
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Does an insecure router bypass the privacy guarantee of a VPN connection?
If I have a router that has a vulnerability that allows an attacker to gain full control it, does using a VPN on the network with the said router prevent an attacker from being able to snoop on the ...
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How does malware enter the computer and take control on a binary or machine code level?
Malware can enter a computer in various ways, but I would like to know how it is able to simply use 0's and 1's and machine code to take over a computer and how it can stay hidden from antivirus ...
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What are some advanced background topics I'll need for distributed systems and networks research?
I am a new graduate student in Computer Science who would like to be able to read and understand modern and new distributed systems research papers. My current background / courses and understanding ...
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Manually Performing ECB & CBC
I am learning about block ciphers and while I understand the concept of Electronic Codeblock mode and cipher block chaining, I could not find any relevant practical examples online. Can someone ...
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encrypt with permutation ciphers
I came across this question:
You are given a permutation cipher defined by the bijection t: N -> N where,
...
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Problem with understanding Multi-party security circuit for secure stable matching
I am reading the following paper:
MPCircuits: Optimized Circuit Generation for Secure Multi-Party Computation
Paper Link
I have following question:
We have two groups shown in the circuit. Why we ...
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Accessible CS Math Job [closed]
I am a CS undergrad and a huge enthusiast of pure math. I have been doing competitive programming and proofs for a while. My ambition is to become an academic in theoretical computer science. The ...
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Decryption of RSA
How can we decrypt an RSA message if we only have the public key?
For example,
Message:
21556870,12228498
Public Key: ...
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Protecting a specific sized message with some limitations
So I make a research on my own. I have a device it allows a 64bit message. I wanted to secure it but I 64bits arent just enough to hash it and encrypt it. Is there really any good Hash function out ...
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Why is a threshold determined for Byzantine Fault Tolerance of an "Asynchronous" network? (where it cannot tolerate even one faulty node)
In following answer (LINK: https://bitcoin.stackexchange.com/a/58908/41513), it has been shown that for Asynchronous Byzantine Agreement:
"we cannot tolerate 1/3 or more of the nodes being ...
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Database that contains timespans of cyber attacks in the web
for a project I need to evaluate a model, that tries to predict wether a certain cyber-attack (i.e. connection to a low level honeypot) is just a random access, a new attack-wave or an already known ...
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Two way communication using asymmetric encryption
According to image 1, for two way communication, each person needs to generate a pair of keys. However, according to image 2, only one pair of keys is required for two way communication. Thanks to ...
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Historical examples of bad security policies/mechanisms that we got stuck with through switching costs?
The following process seems to be a recurring one:
Initial design. Commercial organisations invent and implement a design that seems at the time to work.
Problem discovered, new design suggested. Due ...
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Is "capability-based security" vs "hierarchical-protection-domain based security" a false dichotomy?
The wikipedia page on capability-based security states:
Capability-based security is to be contrasted with an approach that uses hierarchical protection domains.
However, in order to implement ...
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Why do we need full-fledged workstations running massive OSes with massive software?
I've grown up with computers. While watching old computer TV programmes and documentaries and reading the news about constant issues with these modern systems -- everything from the sheer amount of ...
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In Baggy Bounds Checking, why is an error raised when accessing more than half the slot size of the end boundary of an allocated memory?
In the second notes of MIT's Computer Systems Security class (6.858), there is this particular (slightly modified) snippet.
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Problem with understanding the Mathematical Equations related to Testing Tool
I have downloaded the slides from the site:
[Compliance and Violation Patterns
It says No writes after calls. I can understand this concept. It’s a remedy for reentrancy problem. But it shows ...
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What are Surnames' dataset usages?
I have found a dataset which involves surnames dispersion around the world that sorted by population which I use it for a name recommender system.
Its readme page caught my attention because it has ...
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L1 Cache Missing Timing Attack
I'm trying to understand Section 3: L1 Cache Missing in the paper Cache Missing for Fun and Profit. I'm stuck on trying to figure out how the covert channel is ...
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Weaknesses arising from using same key in both channel directions
I came across the following question:
Which of the following risk may arise, when same key is used to encrypt both directions of a communication channel, that are not present if using different keys ...
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When compiled into binary, what signifies the end of a string? How can this be differentiated from user input which compiles to the same binary?
Apologies for the strange title, this is one of those questions I can't find through a Google search just because I don't even know what I'm supposed to be searching for.
As I understand it, programs ...
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Are Physical 2-Person Lock Systems Informed by The Byzantine Generals Problem
The Byzantine Generals Problem says a set of generals who are greater than 2/3rds loyal is required to guarantee that securely issuing an order is possible the loyal generals.
Because of this, I am ...
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Why don't most websites I visit seem to use TLS with Ephemeral Diffie-Hellman?
When I click "view certificate," under Public Key Algorithm it usually says "RSA Encryption" or "Elliptic Curve Public Key." I assume this is the algorithm used to agree on a premaster secret (...
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Can you prevent a man in the middle from reading the message?
I have heard about all these Man-In-The-Middle Attack preventions and I am wondering, how this can possibly work if the man in the middle only listens to your stream and does not want to change the ...
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