Questions tagged [security]

Questions about matters of computer, software and communication security, that is how to protect systems against attacks.

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21 views

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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Is it possible to design features that block “lifting” of copyrighted pictures using the computer (i.e. no external camera)?

Is it possible to design features that block "lifting" of copyrighted pictures using the computer (i.e. no external camera)? That is, is it possible to prevent "accidental use of ...
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12 views

Functionning of the eviction set for Prime and Probe

I have to write a report about Prime and Probe, more specifically about its eviction set method, and there are two notions that remain blurry for me : To find the set, we use huge pages like it's ...
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39 views

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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1answer
30 views

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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1answer
41 views

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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33 views

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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1answer
44 views

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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21 views

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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1answer
33 views

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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29 views

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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2answers
68 views

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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29 views

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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1answer
38 views

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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25 views

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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2answers
149 views

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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27 views

Is there any kind of secure computer system on the horizon?

I'm going to attempt to be as concise as possible, given this highly complicated subject. However, some basic things need to be said here to properly "paint the picture", so kindly don't see it as a "...
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1answer
55 views

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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1answer
44 views

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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13answers
10k views

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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23 views

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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1answer
7 views

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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1answer
52 views

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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0answers
54 views

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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1answer
32 views

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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1answer
33 views

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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18 views

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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2answers
92 views

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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2answers
834 views

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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3answers
107 views

How long does it take to crack a password by brute force

My computer teacher says that hackers can know any password by simply writing a permutation combination program and it will take around 21 days. Is this true?
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1answer
95 views

Matrix to Multi-level security

How to convert access control matrix to Bell-LaPadula. Can teach me step by step What best way to control converting Bell-LaPadula Model lattice using Access Control Matrix Matrix GIVEN $\quad\quad\...
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1answer
348 views

How pictures and videos are usually loaded in Memory? [closed]

Lets assume I'm talking about Jpeg and Mp4 and a general video player(not sure if different ones load it differently, if they do please tell) So do video players (process) usually load the entire ...
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1answer
196 views

NX Bit in x86 vs x86_64

I've been reading about how the kernel manages memory in x86 from this popular blog post(https://manybutfinite.com/post/how-the-kernel-manages-your-memory/) and had a few questions. There is a part ...
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2answers
83 views

Password authentication over an insecure connection

I was thinking a way to send password to server secure way without using secure connection,I found one solution.I want to find flaw in this.(Note: I am begginer,dont judge me, I know little about ...
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0answers
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Agreeing on a Time in a Trustless Network

Imagine a chord-like network $N$. each machine $m \in N$ is directly connected to $N_m \subset N$. Without relying on official timeservers, I want all machines to synchronize to some time with ...
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1answer
30 views

how to defend against DOS caused by SYN cookies? [closed]

i have read about SYN cookies and i understood that they help to avoid DOS .. BUt my prof wants an answer as how SYN cookies can be used to cause DOS and how can it be avoided ? any help woul dbe ...
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110 views

How does a vpn connection work?

I have been looking into vpn (virtual private network). And I wanted to know more about the theory, how does it work really: what does it do with the packages? why is it secure? (or why can it be ...
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1answer
219 views

How does a buffer overrun corrupt the return address?

I got stuck on the following note while reading a paper about computer security: The stack mixes program data and control data – by overrunning buffers on the stack we can corrupt the return ...
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1answer
35 views

Can SSL be hacked if we know some of plain data?

As I know, SSL/HTTPS is two stage, first stage is public key encryption/decryption which transfers key of the second stage which is symmetric. It is true we don't have key, but we can have some of ...
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1answer
25 views

Formally modelling and describing access rights

Is there a formal theory or framework described in text books that models access rights in a mathematical way. I would expect things similar to the following: We have data (objects). We have ...
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30 views

Secrecy rate of eavesdropper channel?

I want to find secrecy rate of a main channel in case of Gaussian broadcast channel. e.g. I have a single transmitter and a receiver where eavesdropper wants to eavesdrop the communication over ...
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2answers
39 views

Would limiting the number of operations in a transaction prevent SQL injection?

In my understanding all SQL injections need to add another operation to the one intended by the programmer. For example, a badly written query: ...
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1answer
82 views

How is tamper-proofing of software evaluated for effectiveness?

How is tamper-proofing of software evaluated for effectiveness? I've been implementing a few algorithms listed within Surreptitious Software: Obfuscation, Watermarking, and Tamperproofing for ...
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0answers
77 views

Importance of Needham–Schroeder Protocol

I'm working on a paper about model checking on cryptographic protocols and many of the papers I have read, base their approaches in the Needham-Schroeder protocol. I undestand this was one of the ...
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3answers
238 views

Can software itself be encrypted?

Imagine that I need to install my server in a remote location, so my algorithm can do something fancy (collocation of server at a financial exchange is how I thought of this question, but it applies ...
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4answers
200 views

Using two hash functions for increased password security?

Forgive me for my brief knowledge on hash functions as I am not from a computer science background, however I am researching password security for my thesis and have been looking into hashing ...
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2answers
606 views

Computer Security versions of the Halting Problem

I'm plenty familiar with the Halting Problem for Turing Machines. It occurred to me after reading several posts on this site that it would be interesting, educational and useful to start a list of ...
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1answer
84 views

Are there any examples of programming synthesis in vulnerability research?

Program Synthesis To borrow from Microsoft: Program synthesis is the task of automatically discovering an executable piece of code given user intent expressed using various forms of constraints ...
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0answers
81 views

Could an OS relinquish control back to the bootloader?

I'm wondering if it is feasible for an OS to return control back to the bootloader, and boot a second OS after itself. Reason being -- I've been musing on bootkits, and wondering if it would be ...
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118 views

What is an access control graph?

A question I came across describes a scenario of an information system in a clerical office and states- "Identify the sets of S={subjects}, O={objects} and P={privileges} for the above systems of the ...