Stack Overflow
Stack Overflow

Questions tagged [ctf]

In a computer hacking context, a Capture The Flag (CTF) challenge invites participants to extract a hidden piece of information called a "flag" (usually a short string of ASCII text) from vulnerable online systems or downloadable files through the application of skills in various fields such as cryptography, steganography and reverse engineering. Typically this involves bypassing poorly-implemented security measures.

In a computer hacking context, a Capture The Flag (CTF) challenge invites participants to extract a hidden piece of information called a "flag" (usually a short string of ASCII text) from vulnerable online systems or downloadable files through the application of skills in various fields such as , and . Typically this involves bypassing poorly-implemented security measures.

162 questions
-1
votes
1 answer

Need help in RSA, cipher text in hex and also has alphabets

I am solving a CTF where I am given public key, private key and ciphertext. Challenge is VeryAsymmetrical. I have extracted info from private key like n, e etc. using…
Suvid Singhal
  • 1
  • 2
-2
votes
0 answers

Reverse Engineer ELF binary

This is a reverse engineering challenge from a CTF event. The clue/hint is: Well ol' chap, it seems we have ourselves another puzzle! I just can't picture what this one might be... Well, there's no time to waste shuffling about, we must begin! It's…
Keiran
  • 31
  • 6
-2
votes
1 answer

Hidden message in a picture

I'd like to read a hidden message in the following picture: The message is supposed to look like CTF{Something}. I've tried to find out how to read it for hours without success. So far, I've tried to read the RGB values of each cell. For instance,…
Manitoba
  • 8,522
  • 11
  • 60
  • 122
-2
votes
1 answer

why "add #0x10, sp" adds 16 bits to the sp while "add #0x8, sp" adds only 8? (microcorruption CTF, "cusco" stage)

in the cusco challenge of microcorruption CTF I noticed that after line 453a the sp adds 16 to the sp value while on line 4476 it adds only 8. why does it happen? by the way if there are easier challenges you know of to practice my reverse…
omriMB
  • 1
  • 2
-2
votes
1 answer

Header of file compiled by bluespec

I have a file with the .bo extension. After some researches it seems be built with bluespec which is use with risc-V architecture. My objective is to reverse this file. When i do: file myfile.bo myfile.bo: data So, I don't know if it's a good…
Radion
  • 1
  • 3
-2
votes
2 answers

How to decode rsa with public and private key

I have this public and private key, how to i decode this ? thank you, very much. -----BEGIN PUBLIC…
Đỗ Văn Hòa
  • 9
-3
votes
1 answer

Im working on a CTF project using SecGen and I have everything install and when I run the command to run SecGen this is what I get

enter image description here Here is a screen shot of the commands.
JediBDS
  • 1
  • 1
-3
votes
1 answer

How secure would this encryption be?

I had an idea, to encrypt a string with bytes generated by python's pseudo random generator, to create essentially a one time pad, which should be secure, the question is in relation to the seeding of the random generator to create the pad. Assuming…
lonny
  • 135
  • 1
  • 4
-3
votes
1 answer

Why this PHP comparison it wont return True

Why this PHP comparison it wont return True and is there a way i can make it return true ? "; if($first ==…
Edit316
  • 1
  • 1
-3
votes
2 answers

CTF RSA decrypt using N, c, e

Giving N, e, c as follows: n = 35390004486354300347521848565413257959442624589297688131017877221807025004928966206454752329594506530598099849274956709610488234955109039874355077958460196991750855650029096905451 e = 65537 c =…
John L
  • 39
  • 1
  • 1
  • 2
-4
votes
3 answers

Whats a value of x such that both x + 1 == x and x * 2 == x is true?

Title basically says it all. My friend gave me this as a challenge he solved in some CTF he is doing. I have thought about it for a while and can not figure it out. Also, INFINITY isn't a valid answer. Thanks.
user14894087
  • 25
  • 3
1 2 3
…
10
11