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## How to encrypt and decrypt files with bouncy castle (DES) in netbeans java?

How can I encrypt and decrypt files (not strings) with bouncy castle (DESEngine)? I have searched before but could not find help.

## Slow one-way pseudorandom permutation?

I'm looking for a slow keyed trapdoor one-way pseudorandom permutation; or in other words a block cipher $E_K: P\in\{0,1\}^b\mapsto C\in\{0,1\}^b$ with moderate block size $b\approx 64$ bits, wide key …

1 hour ago

## Future Configuration Design for Web Application

I have a large rails application which configures the setup of a factory. The application basically have several pages which allow CRUD operations for different entities, and there are many ...

## Decryption-Only method in C#

I'm looking for a secured way to implement a license file for my application, with flags and features. I read about Asymmetric key mechanism in C#, but the RSA purpose is little opposite from what I …

## Alphabetic Substitution with Symbols

I was reading on a site about the Zodiac Killer and how he used a basic substitution cipher, but instead of substituting english letters and characters he substituted symbols. I was wondering, if you …

## Having links to an included file by LaTeX PdfPages

How can you maintain the links in your pdf fileA which contains links to itself in the fileB which includes FileA? FileA has internal links to itself. I include it to FileB by Pdfpages such that ...

2 hours ago

## When using pdfpages in LaTeX, how to avoid page breaks before the first page ?

I am creating a large LaTeX document, and my appendix has reproductions of several booklets that I have as PDFs. I am trying to create a section header and then include the pages at a slightly lower …

2 hours ago

## javac not working in windows command prompt

I'm trying to use javac with the windows command prompt, but its not working. After adding the directory "C:\Program Files\Java\jdk1.6.0_16\bin\" to the end of the environment path variable, the java …

## How do I configure Perfect Forward Secrecy in Windows Azure (OS, or Websites)

I want to move my website to Windows Azure, but need to make sure that I'm using PFS on all my instances and roles. (regular web roles and Websites as well) How do I configure this so that each ...

## Will the bitcoin value keep rising at steady rate, if bitcoin mining is stopped right now

If no new coins are created by mining after 12 million bitcoins as of today, what kind of impact will it have on bitcoin value. Transaction fees will still be set for confirmations.

4 hours ago

## Is there a policy about font size?

I notice that recent posts are using \large in LaTeX when it is not really needed or similarly display math in the title of the post. The impression is that it is just pure visual competition for ...

5 hours ago

## Critique of FilterInputStream and FilterOutputStream classes

I'm working my way through The Java Programming Language, Fourth Edition - The Java Series. This is Exercise Exercise 20.3: Create a pair of Filter stream classes that encrypt bytes using any …

6 hours ago

## Does minimizing ANY type of energy ALWAYS predict a state of equilibrium?

My intuition says no, but I am having trouble coming up with concrete examples. I know that minimizing Gibbs free energy predicts a state of equilibrium, while minimizing kinetic or internal energy …

8 hours ago

## Can you help me with this DES variant analysis?

I'm struggling with some DES variant that I got as an exercise (exercise taken from Katz-Lindell Ex5.14). The variant is as follows: The left half of the master key is used to derive all the ...

## Evaluating Latex Math in Javascript

I am working on a html-based calculator, and I want to render an expression, then evaluate it, and all of this must be done in Javascript. I would prefer for the expression to be written in LaTeX, and …

## File ecnryption using DES decrypting garbage - C#

I am trying to write a simple file encrypter in C# using DESCryptoServiceProvider. The file format I am encrypting is .jpg. The encryption appears to look fine, but when I decrypt the encrypted file I …

## PRP representation size

I'm now studying the block cipher - SPN construction and realized that it uses several small PRPs instead a big one for saving memory (or that is one of the reasons). Why does the PRP with ...

12 hours ago

## Asymmetric block ciphers?

Any block cipher transforms a block of $N$ bits into another block of $N$ bits based on a $\mathcal{K}$ bit key. This can be considered to be a substitution cipher on an alphabet consisting of $2^N$ …

## Is it feasible to implement my encoding module in multi-threaded mode?

I am working on data integrity protection scheme, as described at “FMSR-DIP: Enabling Data Integrity Protection in Regenerating-Coding-Based Cloud Storage ”, in which my DIP encoding module works on a …

13 hours ago

## What is a good analogy (which a layperson would understand) for the process of Bitcoin mining?

I will be explaining Bitcoin to a non-technical group and I am hoping somebody can provide me with a very basic visual analogy of the crypto-currency mining process. My half-baked idea, was to ...

## How to place a character below a function in Latex?

Is it possible to place a character or a formula below an other part of a larger formula in Latex? foo f(x) = ... x In case that this example is not clear. I'd like to make one of my custom ...

14 hours ago

How can I generate JavaDocs for an Android project using the new Gradle build system? Here is what I have come up with but it doesn't work. task generateJavadoc(type: Javadoc) { source = ...

## Why is it that researchers prefer finding secure software solutions over secure hardware solutions?

My understanding is crypto researchers tend to prefer solving a problem in software without the need for secure hardware. Why is this? What is the big problem with using secure hardware if the ...

15 hours ago

## Find the key to a Vigenère cipher, given known ciphertext and plaintext

I have the ciphertext and the plaintext. Is it possible to know the key? If not, what do I need to find it?

## Asymmetric Cryptography Confusion - 'Sign' a file to guarantee its source

What I want to do is use asymmetric crypto to guarantee that a file comes from a source. I have software that runs on lots of wireless devices, and each of those has a license file with an encrypted …

## Properties of joint entropy

I'm trying to show the following, but am stuck For discrete random variables $X$ and $Y$, show $$H(X,Y)\geq \max\{H(X),H(Y)\}$$ where $H$ represents entropy

## Caesar Cipher work

firstly, i'm sorry for my horrible english, i'm french (yeah you can blame me ahah :P), it's my first time on this forum, i'm coming in stackoverflow because lot of people said me "go to stackoverflow …

17 hours ago

## Why should I use Authenticated Encryption instead of just encryption?

There are various different modes of operation for block cipher use, some of which provide "encryption" and some of which provide authenticated encryption. Why should I use an authenticated ...

Define the following recurrence for $n = 1, 2, \cdots$ $T(n) = ( 1 - \operatorname{H}(\frac{1 - P^{\frac{1}{n}}}{2}))^n$ where $0 < P < 1$ is a constant, function $\operatorname{H}(\cdot)$ is …