Linked Questions

-5 votes
2 answers
457 views

Ignorant Biologist in need of AES-128 CBC PKCS5 encryption key

I'm a biologist frantically trying to understand the world of cryptography overnight for research- please ignore my ignorance. I was given a large body of text to crack that is encrypted with AES-128 ...
Boi WUT's user avatar
13 votes
1 answer
1k views

When did Kerckhoffs's principle become fully accepted in design and practice of modern ciphers?

Kerckhoffs's principle is named after a publication over 130 years old. Yet it is still something that is commonly misunderstood and challenged by newcomers to cryptography. This question from Open ...
Neil Slater's user avatar
  • 1,119
9 votes
1 answer
2k views

Why are cryptography algorithms not exported to certain countries?

There have been strict laws about the export of crypto software to certain countries. I can understand the intent, but never gauged the fact that there is nothing stopping these countries from ...
eminemence's user avatar
7 votes
1 answer
457 views

Does a conditional statement depending on a round number introduce timing attack problems?

In a cryptographic implementation I’m playing with, there’s a round function which includes a conditional if statement. Stripping the superfluous stuff, the C ...
e-sushi's user avatar
  • 17.9k
6 votes
1 answer
1k views

What is 'key agility' in relation to symmetric-key encryption?

I sometimes see, in discussions of symmetric ciphers, reference to the 'key agility' of a particular algorithm. It seems to be related to the difficulty of switching encryption keys, but I don't ...
pg1989's user avatar
  • 4,646
4 votes
1 answer
1k views

Making my steganography code more hard to detect and crack

I'm doing a college project about digital image steganography on MATLAB. So far i've been able to get the help i needed from cool guys on stackoverflow but i now need to make my algorithm more hard to ...
Ahmed Ihsan Tawfeeq's user avatar
3 votes
1 answer
3k views

How vulnerable is one-time pad (OTP) encryption, if the OTP is used twice, with a random substitution scheme

After reading up on the one-time pad (OTP) encryption method, I could see how it would offer unbreakable encryption if used properly. Moreover, I looked at how the OTP could be broken if the OTP-key ...
Horst's user avatar
  • 143
3 votes
1 answer
2k views

How do you test the security of your cipher?

I got asked this question and I didn't know what to answer. How do you test the security of your cipher? What comes to my mind now would be to test it with famous attacks: padding attacks, ...
David 天宇 Wong's user avatar
2 votes
1 answer
420 views

Choosing encryption algorithms and protocols in military systems

Militaries use their own cryptographic algorithms, those of a private third party, or ones that are openly available. However, fear of a backdoor having been planted in publicly-available encryption ...
R1w's user avatar
  • 1,960
2 votes
1 answer
729 views

Inverting One-Way Functions

One of the conditions that a one-way function has to satisfy is the following: $$Pr[A(f(x))\in f^{-1}(f(x))] \leq negl(n)$$ Now, suppose that we have the following function that's not one way: $$f(x)...
GraceTone's user avatar
1 vote
1 answer
309 views

Value of new symmetric key algorithm

When I was in grad school, I invented (discovered?) a new PRNG algorithm. This algorithm has an infinite period length (given infinite memory). This in itself cannot be new, because all you need to ...
Jacob Levinson's user avatar
0 votes
1 answer
816 views

Is my high school cryptography/steganography science fair project practical?

I'm a 12th grade student interested in a science project in cryptography and steganography for my school's science fair. I chose this path of computer science partly because my coding skills are weak (...
Ingrid's user avatar
  • 19
0 votes
1 answer
446 views

Is flipping the bit belonging to encryption?

Just a simple question about encryption. If we have an image, we transform into a bits and we get 1001001... Then, I flip the bits into 0110110... manually. Can I said that I have done an image ...
alvin19's user avatar
  • 33
-2 votes
1 answer
1k views

Is it possible to attack an SHA-256 hash seeded with PHP’s mt_rand function?

Is it possible to attack this construction if the attacker only knows the hash? ...
James Walker's user avatar
1 vote
0 answers
71 views

In symmetric searchable encryption are the algorithms public? [duplicate]

If a user (other than the data owner) possesses the secret key in symmetric searchable encryption scheme are they able to run the trapdoor algorithm, or is this not publicly available?
crypto1's user avatar
  • 11

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