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

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0answers
12 views

Share PDF files with permissions [closed]

in my office we share PDF Files company wide via email but they have to email us back to say who they're sending the PDF to. Is there a way to automate this process maybe using an online hosting ...
7
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2answers
79 views

Zero-knowledge proof: Abstract example

So I was reading about ZKP on wikipedia, the abstract example in summary goes like this: Peggy wants to prove to Victor that she knows the secret to a door inside a cave that connect A and B ...
1
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0answers
33 views

How Can a Network Server Identify a Specific Computer, Is There a Computer Fingerprint?

Most of websites put some restrictions on how to use their services; the following paragraphs are taken from “Terms of Service” of such website: Only one account per computer is allowed to view ads. ...
2
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1answer
44 views

User recognition through keystroke pattern

Hello thank you for taking time looking at this question. Is it possible to determine the keystroke patterns for a certain user? My idea is that, when the user enters their username & password it ...
3
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1answer
28 views

Why do ACLs (access control lists) have better persistence than capabilities?

Although I understand the principles on which both ACLs and Capabilities operate, I do not see why on system restart it would be favourable to store privileges by using ACLs, instead of capabilities ...
2
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1answer
44 views

What exactly would stop me from registering a domain from my own nameserver? [closed]

Can I just make a nameserver and claim away? Are there implemented measures to stop this from happening?
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1answer
31 views

will breaking not used anymore RSA codes in the future affect privacy?

just read and watch some stuff on how RSA works. main idea seems to be if someone steals your communication he cannot decode it anyway. but let's say someone steals it and keeps it along with current ...
3
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1answer
25 views

Oblivious RAM write protection

I'm trying to understand how oblivious RAM works, specifically path oblivious RAM. While I understand how this technique offers protection when reading data - multiple randomly distributed reads ...
-1
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1answer
27 views

Which “ID” extraction is correct?

This question related to attack on the LMAP++ the result of extracting ID from the messages. In Passive Attack on RFID LMAP++ Authentication Protocolm, page 188 ...
7
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2answers
71 views

Running an algorithm on data remotely and ensuring answer has not been tampered with

I´ve been thinking about this particular computing/crypto/database problem for years and I just want to know if there are already solutions to it. To be honest I don´t even know what field this ...
2
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1answer
30 views

Can Eve impersonate Alice or Bob by using a replay attack?

For my computer science study, I have to design a replay attack (if possible) for the following authentication protocols. I use the standard security protocol notation. In these protocols, $A$ is ...
1
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2answers
41 views

Why is the star property important

According to the Bell-Lapadula model, write access is only to Subject $S$ on object $O$ provided if: $L(S) \leq L(O)$ where $L$ is the clearance level for $S$ and classification for $O$. This seams ...
0
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1answer
38 views

Validating authenticity of a file

Suppose there's an entity which produces files. User A has one of those files and decides to send it to user B. How can user B validate the authenticity of the file without communicating with the ...
3
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0answers
54 views

How is Chinese Remainder Theorem used in the proof of correctness for RSA

Question At the very end of (most) proofs of RSA's correctness we have something like $$m^{ed}\equiv m\pmod p$$ $$m^{ed}\equiv m\pmod q$$ Therefore by the Chinese Remainder Theorem (CRT) $$m^{ed}\...
2
votes
1answer
46 views

How to make a “Secure by Design” client-server communication?

Is there a way to have a secure by design client-server communication in a sense that the server can check if the client is not a modified version? What I'd like to do is give the user access to both ...
2
votes
3answers
40 views

Existence of functions that only tests memberships without revealing any information about the members

Given a set of strings $\{s_1, s_2, \cdots, s_n\}$, is there a way to encode them to a program $P$, such that given some string,$s$, the program can test the membership efficiently (deterministically ...
4
votes
1answer
601 views

What is oblivious RAM and how does it work?

Could anybody explain me what exactly oblivious RAM is? I found the following explanation which makes it kind of clear to me, but I would like to get a sense of the technical aspects: Encryption ...
36
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7answers
8k views

Keeping a String Secret in (Open) Source Code

I have finished developing an app for Android and intend to publish it with GPL -- I want it to be open source. However, the nature of the application (a game) is that it asks riddles and has the ...
2
votes
1answer
90 views

Is a very long plain text password harder to crack than a short complicated password? [closed]

Is it true that a password consisting of the alphabet, even of common known names is much harder to find for a computer program than a short password, even though it uses numbers and other characters?
0
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1answer
30 views

Can file snapshots aid in detecting malware?

I noticed certain programs have a feature that can have a 'snapshot' of a file from a certaim time and compare it to a more recent snapshot of the file. If one's system has a snapshot of a program ...
0
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1answer
41 views

Two Step Verification. 4 digits vs 6 digits

From a security level standpoint (such as Server, DataBase, Token Code, Authorization, Authentication, etc.) in regarding the Two Step Verification, usually Apple send a total of 4 digits security ...
12
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2answers
626 views

How does an operating system create entropy for random seeds?

On Linux, the files /dev/random and /dev/urandom files are the blocking and non-blocking (respectively) sources of pseudo-random ...
1
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2answers
45 views

Handling TOCTTOU with system calls

What are some of the best practices when implementing system call functionality for handling/avoiding "Time of check to time of use" (TOCTTOU) security issues?
1
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0answers
220 views

How does one guarantee that the commutative, associative and distributive properties hold for a type?

While most main stream programming languages allow for user defined types that can have the following properties: associative commutative distributive the only way I know of that this can ...
5
votes
3answers
307 views

Would it ever be possible for computer viruses to evolve new “genes” to allow them to perform their job?

As an A-level Biology student, I have thought a lot about the links with Biology and Computer Science, and something that often comes to mind are the links between Immunology and Computer Security/...
5
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1answer
166 views

What is the complete version of the paper: “How to Generate and Exchange Secrets (extended abstract)” by Andrew Yao?

I've found numerous places that claim that the paper "How to Generate and Exchange Secrets" by Andrew Yao introduces garbled circuits as a solution to the secure multiparty computation problem. ...
2
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1answer
51 views

Access control matrices: who are the subjects: users or processes?

I'm studying the basics of security in computers. The doubt I have is that the access control matrix is presented as a matrix whose rows are the subjects and the columns are the objects. Also subjects ...
1
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1answer
70 views

Logic applications and security protocols references request

I'm a student of logic and I'm interested in looking at logic applications, of which I am told there are many, in computer science and allied areas. I've seen some applications. More specifically, I ...
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3answers
152 views

Computer Science - System Security : How to Prove that KISS principle is Implemented in Security? [closed]

I basically have this homework question that needs me to support the below statement. Any suggestions on how i could go around proving it ? the Exact Question was : "The KISS principle is ...
8
votes
6answers
279 views

Could program verification techniques prevent bugs of the genre of Heartbleed from occurring?

On the matter of the Heartbleed bug, Bruce Schneier wrote in his Crypto-Gram of 15th April: '"Catastrophic" is the right word. On the scale of 1 to 10, this is an 11.' I read several years ago that a ...
4
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2answers
173 views

Is it theoretically exist a computer that never affected by computer virus? [closed]

Is it theoretically exist a computer that never affected by computer virus? just wonder if there could be a revolution on the computer?
1
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2answers
223 views

Understanding Return Oriented Programming on Harvard Architecture

I'm currently reading this paper: Code injection attacks on Harvard-architecture devices (ACM) (pdf) I understand the basics of what the attack is trying to do, but one thing really bothers me. If ...
5
votes
2answers
138 views

In general terms, how could the Thompson Hack be implemented in Microcode?

In his lecture Reflections on Trusting Trust, Ken Thompson describes a virus that infects a compiler; the infected compiler installs backdoors into programs, but the key part is that the infected ...
3
votes
2answers
214 views

Dangerous interrupts

Let's say we have a fictional operating system in the user mode. Whenever an interrupt or a trap occurs, the os would switch to the Kernel mode jumping to the address determined from the interrupt ...
2
votes
2answers
690 views

Handling untrusted string input in printf in C [closed]

I stumbled upon the MSDN Best Practices for Code Review. Under the section “Untrusted Inputs”, I found following which I didn't understand properly. Why is the following considered safe? ...
5
votes
1answer
76 views

Anonymization of dataset preserving unique identities

The $k$-anonymization paradigm (and its refinements) means to create datasets where every tuple is identical with $k-1$ others. However I'm in a situation where people are in the dataset many times. ...
9
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3answers
724 views

What is the branch of Computer Science that studies how Anti Virus programs work?

It is a trivial exercise in finite automata to show that there is no algorithm that can detect all the viruses, yet there are many software companies selling Anti Virus Software. Is there any part of ...
8
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3answers
503 views

Key secrecy vs Algorithm secrecy

it's a well known statement that "Cryptographic security must rely on a secret key instead of a secret algorithm." I would like to ask about some details about it. And which are their differences? ...
9
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1answer
458 views

Is WPA2 with pre-shared key an example of a zero-knowledge proof?

When setting up an access point and selecting WPA2, one must manually enter a pre-shared key (a password), PSK, into both the AP and the STA. Both parties, AP and STA, must authenticate each other. ...
3
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2answers
720 views

Can the Bell-LaPadula model emulate the Chinese Wall model?

I have been reading on security policies and the question wether Bell-LaPadula can be used to implement Chinese Wall. Does anyone know more about it?
3
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1answer
363 views

Security Lattice Construction

I am having a problem trying to solve a question on a past paper asking to design a security lattice. Here is the question: The AB model (Almost Biba) is a model for expressing integrity policies ...
1
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1answer
110 views

Where can I find good study material on Role Mining?

I need to cover these topics in Role Mining. If anyone knows good site which well summarizes the topics and concepts are well explained please help out. Basic role mining problem • Delta-approx RMP • ...
11
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1answer
1k views

How does Stack Inspection work?

This is precursor to my other, more advanced question about Stack Inspection. Stack Inspection is a security mechanism introduced in the JVM to deal with running code originating from locations ...
8
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2answers
883 views

Limitations of Stack Inspection

This is a follow up to the How does Stack Inspection work? that explores the notion in more detail Stack inspection is a mechanism for ensuring security in the context of the JVM and CLR virtual ...
10
votes
2answers
2k views

How does a wifi password encrypt data using WEP and WPA?

How does the password that we enter (to connect to a wireless network) encrypt the data on the wireless network? Through my reading I am not sure if the password that we enter is the same as the ...
5
votes
2answers
195 views

Fine-grained security models for XML data

Access control models are typically very coarse-grained, allowing one access to a resource (possibly with some combination of read/write/execute permission) or exclude such access. Some models of ...