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1 answer

Serpent 256bit key wrong round keys

Assume that we have this 256bit key: 15FC0D48 D7F8199C BE399183 4D96F327 10000000 00000000 00000000 On first 0-7 keys we can't apply formula wi=(wi-8 xor wi-5 xor wi-3 xor wi-1 xor phi xor ...

1 answers | 9 mins ago by nmZ on Cryptography crypto.stackexchange.com
0 answers

How do I read integers from a file and put them into an array with a while loop

so there's something in my program that is not going the way I feel like it should go. If I could get some help I would appreciate it. I'll explain how it's supposed to work first and follow up with ...

0 answers

How do I display pi in LaTeX like Don?

Way back in 1979, Donald Knuth, tried to give the feeling that π is irrational using the idea of infinite sequence of smaller and smaller font sizes like what I have tried to do here using HTML and ...

2 answers

How can the microstates be measured with zero energy expenditure?

James P. Sethna. Statistical Mechanics. Exercise 5.2: What prevents a Maxwellian demon from using an atom in an unknown state to extract work? The demon must first measure which side of the ...

1 answer

xcode ios HMAC SHA 256 hashing

So I'm trying to figure out how to do a hmacshad256 hash on ios as that's the hash I did for the wcf service api I made. I've been trying to look for some info about it but would usually just end up ...

1 answer

How to decrypt in Java strings that have been encrypted using JS crypto

What would be the equivalent of this JS code in Java, using javax.crypto.xxx? encryptString : function encryptString(str, password) { var cipher = crypto.createCipher("aes128", password); ...

1 answers | 2 hours ago by n0rm9n on Stack Overflow stackoverflow.com
0 answers

Prove counter mode of operation and CBC mode are CPA secure when pseudorandom permutations

I know counter mode can be CPA secure, when used with block ciphers modeled as random permutations. If we use pseudorandom permutations, is it still cpa secure? could anyone show me the prove? How ...

1 answer

Encrypt a file for random access but only after an initial read of the whole file

I'm symmetrically encrypting a file (using a random salt and a user supplied password with PKCS5S2, i.e., nothing special) and I need to be able to access it randomly. Therefore I'm using a stream ...

2 answers

Why can we say that $\bar{d}Q=TdS$?

When we introduce entropy we do this by saying that: $$\bar{d}Q=TdS.$$ Now I was wondering why this should be true? I know that by looking at a Carnot cycle, we do get this relation for reversible ...

1 answer

Committing Bilinear equation in Groth-Sahai framework

Groth-Sahai framework enables us to commit to QE, MSME, PP equations. Now, is the equation below committable in GS framework? A bilinear map $e: G_1 \times G_2 \rightarrow G_T$. $g_1 \in G_1$ and ...

0 answers

attack on RSA (factoring when knowing e and d)

This is the problem, I have to explain how works the algorithm on the image with modular arithmetic for a discrete math class., I tried to explain it, but I couldn´t. In the class, I have seen this ...

2 answers

Does google's Crypto.JS AES encryption use PBKDF2 as default?

Does google's Crypto.JS AES encryption use PBKDF2 as default? Some references, but I can't figure out the answer myself: https://code.google.com/p/crypto-js/#The_Cipher_Algorithms ...

1 answer

Are temporary files an issue when opening and editing an encrypted 7z file?

I am new to security and encryption. I want to store important information like passwords and pin codes so I don't forget them. So far I have been using LastPass but I would prefer a solution I ...

1 answers | 5 hours ago by Kaja on Information Security security.stackexchange.com
3 answers

Understanding modular arithmetic in encryption example

I understand modular arithmetic in its basic mathematical form for example: 38 = 2 mod 12 However in the following encryption and decryption code example it is used along with other math and I ...

0 answers

Encrypt Joda DateTime using Jasypt

I used Joda DateTime in one of our recent projects to record timezone-wise date/time information. Correspondingly, I used Jadira Usertype for persisting Joda DateTime objects. Because the date/time ...

1 answer

CryptoJS encrypts AES with passphrase but PHP decrypt needs a key

I am using CryptoJS to encrypt a string: function doHash(msg){ msg = String(msg); var passphrase = 'aggourakia'; var hash = CryptoJS.AES.encrypt(msg, passphrase); var ciphertext= ...

2 answers

Unused array of primitives: what do javac and the JIT compiler do with it?

Suppose I have a method that declares an array of primitives, but doesn't use it: public void frobnicate() { int[] pointless = new int[1000]; System.out.println("bored"); } What will happen ...

1 answer

RSA Encrypt String longer than key

Hei Guys, i'm encryping Strings with JS and a Public Key. I use the JSBN code but the problem is in creating a BigInt. RSA.js does: // Copyright (c) 2005 Tom Wu var m = ...

1 answers | 6 hours ago by Blackbone on Stack Overflow stackoverflow.com
4 answers

Offline Javadoc Server

As not all our development machines have internet access, we want to cache the API docs of various libraries in our local network. I was thinking of a webapp that handles caching and listing the ...

4 answers | 6 hours ago by FRotthowe on Stack Overflow stackoverflow.com
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Homomorphic Compression

Can there be an algorithm such that, given plaintext data P,Q, and compression function e, Such that if we treat P and Q as a number (a series of bits): $$\begin{eqnarray*}e(P + Q)& =& e(P) ...

5 answers

Asymmetric vs Symmetric Encryption

I am currently taking a principles of information security class. While talking about different encryption methods a large number of my classmates seem to believe that Asymmetric Encryption is better ...

0 answers

tikz matrix undefined control sequence

I would like to use tkiz matrix but any compilation within a tikz picture ends with error: ! Undefined control sequence. <argument> \pgf@matrix@last@nextcell@options I wonder if there is no ...

0 answers

Desfire EV1 internal authenticate only

We are an foundation creating software for developing countries. Currently we are working with a DESFire EV1 card. We can do an authentication using the ISO 7816-4 INS commands supported by it. Below ...

9 answers

One liner to create passwords in linux?

How do you create a readable password using bash with one line? What if i'm looking for 128 bits of entropy? EDIT By readable I mean the 94 readable ascii characters (without space). It can use less ...

1 answer

Should I use HMAC in this situation

I need to store a big message encrypted on a server. What I am about to do is: Encrypt the message with a AES key; (Authentication) Hash the message with SHA512 and encrypt the hash with RSA priv ...

0 answers

What does “learnable with oracle queries” mean?

I came across the following quotes in reading papers on obfuscation (1, ibid, and 2): The next result follows from the fact that point functions are not exactly learnable (since a uniformly chosen ...

0 answers

Does entropy increases due to gravity?

Imagine travelling to the surface of a neutron star where the very intense gravity would make you weigh 140 trillion times more than we do on earth. It's enough to significantly raise the entropy of ...

1 answer

How to encrypt a string with AES to a string with only specific characters?

I want to use a barcode (code 39) to represent a string, and I want this string to be encrypted using AES. However, I can only display 43 characters with the barcode. How can I encrypt it so that the ...

2 answers

How do I read a string from a text file and stop at a certain character? C++

I'm decrypting an encrypted file that was made with my encryption program. I'll try and explain the whole scenario so everyone gets what exactly my program is doing. My encryption program had the ...

2 answers | 11 hours ago by Cush on Stack Overflow stackoverflow.com
1 answer

Why Future thread doesn't work in background of application?

Today I found a wierd problem. What I want is to check server availability (Particularly SSL checking) once application started and display proper message if server is down. This process should work ...

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