Questions tagged [security]

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

Filter by
Sorted by
Tagged with
0 votes
2 answers
48 views

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 ...
  • 101
1 vote
1 answer
40 views

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 ...
0 votes
0 answers
74 views

Diffie-Hellman with offline attack

There is a protocol that aims to transfer a password securely between the user and the server. The protocol is based on the Diffie-Hellman method. In the protocol, p is a prime number, g is a ...
8 votes
13 answers
6k views

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 ...
  • 215
0 votes
0 answers
40 views

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 &...
3 votes
3 answers
118 views

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 ...
1 vote
0 answers
31 views

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?
0 votes
0 answers
14 views

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" ...
  • 317
1 vote
3 answers
101 views

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 ...
0 votes
1 answer
30 views

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 ...
-2 votes
1 answer
22 views

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 ...
0 votes
1 answer
51 views

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. ...
  • 3
2 votes
3 answers
455 views

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 ...
  • 120
1 vote
1 answer
53 views

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 ...
  • 11
1 vote
0 answers
117 views

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 ...
0 votes
2 answers
36 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? ...
  • 101
1 vote
0 answers
74 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 ...
0 votes
1 answer
59 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 ...
-1 votes
1 answer
71 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 ...
4 votes
0 answers
48 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 ...
  • 41
-2 votes
1 answer
109 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 ...
  • 167
1 vote
2 answers
36 views

encrypt with permutation ciphers

I came across this question: You are given a permutation cipher defined by the bijection t: N -> N where, ...
  • 167
0 votes
1 answer
43 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 ...
1 vote
0 answers
37 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 ...
1 vote
2 answers
132 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: ...
  • 167
0 votes
0 answers
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 ...
2 votes
1 answer
98 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 ...
0 votes
0 answers
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 ...
  • 1
1 vote
2 answers
693 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 ...
  • 113
1 vote
1 answer
66 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 ...
  • 3,382
1 vote
1 answer
117 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 ...
  • 3,382
18 votes
13 answers
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 ...
1 vote
0 answers
43 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. ...
0 votes
1 answer
10 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 ...
2 votes
1 answer
62 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 ...
1 vote
0 answers
65 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 ...
  • 133
1 vote
1 answer
57 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 ...
1 vote
1 answer
38 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 ...
  • 13
1 vote
0 answers
25 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 ...
2 votes
2 answers
188 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 (...
10 votes
2 answers
847 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 ...
  • 287
0 votes
3 answers
359 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?
-1 votes
1 answer
115 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\...
  • 107
1 vote
1 answer
423 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 ...
  • 740
0 votes
1 answer
261 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 ...
2 votes
2 answers
139 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 ...
2 votes
0 answers
47 views

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 ...
0 votes
1 answer
35 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 ...
  • 3
3 votes
0 answers
120 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 ...
  • 131
0 votes
1 answer
355 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 ...