264 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 ...
844 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 ...
1k 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 ...
422 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 ...
953 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 ...
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 ...
2k 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 ...
1k 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, ...
407 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)...
278 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 ...
316 views

### Choosing encryption algorithms and encryption protocols in military systems

Militaries use their own cryptographic algorithms, those of a private third party, or ones that are openly available. But fear of a backdoor having been planted in publicly-available encryption ...
585 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 (...
294 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 ...