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1 answer

md5 hash a large file incrementally?

In the browser, I read in a file using the JS FileReader().readAsBinaryString(). Using the CryptoJS library I can MD5 hash the data. This works fine but I do not know how to handle large files. E.g. ...

0 answers

Executing ecnrypted code?

I want a code 'black box' that receives data inputs, processes those inputs, then sends out the outputs. I want the code to be encrypted, or somehow obfuscated. Is there any known way to do achieve ...

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read/write data using mmap on encrtpted disk

I am working on an encrypted filesystem that encrypts data just before writing it to disk and decrypts it right after reading from disk. any file in disk is useless if not decrypted first. so far I ...

0 answers

RSA with probable primes

I am a bit of a newbie to RSA encryption, so please be patient. I understand that for a 4096 bit RSA, the numbers p and q should be prime. And to have the best security, the p and q should both be ...

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Camel Crypto Fails PGP Decryption (Invalid

I generated a PGP key pair and gave another party the public key. They are encrypting a message and sending it to me. I am using Camel Crypto/PGP to try to decrypt it. I have a simple route setup ...

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SIGINT Challenge #1

Alice, Bob, Carol, and Dan are playing a card game. After they all show their cards, Bob notes that by exchanging two cards the order of the players would be reversed; that is, the player with the ...

3 answers

In RSA, why is it important choosing e so that it is coprime to φ(n)?

When choosing the public exponent e, it is stressed that $e$ must be coprime to $\phi(n)$, i.e. $\gcd(\phi(n), e) = 1$. I know that a common choice is to have $e = 3$ (which requires a good padding ...

1 answer

How to prove the inequality on relative entropy?

Here is the definition of Relative Entropy Now I am only interested in the simplest condition that the index set is finite and discrete, as the naive probability distribution vectors. Now if the ...

1 answers | 3 hours ago by lingou on Mathematics
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Would this method deliver a perfectly non-malleable encryption for at least two blocks?

Say I’m using a 128 bit block cipher and would like to encrypt a 256 bit input that would be divided to two blocks, however I wish that every bit changed in the ciphertext would completely corrupt ...

1 answer

Annotation information missed after compiled with ECJ Compiler

I found the bytecode compiled from ECJ compiler has the annotation information missing. The source code decompiled from bytecode compiled by javac: public class HelloWorldApp { ...

1 answers | 6 hours ago by green on Stack Overflow
1 answer

proper javadoc comments for two classes

Right now I have to write some comments for my code. The code is like: /** * Provide a block grid of customized size and * a block moving back and forth at the center * of the block grid. * ...

1 answers | 7 hours ago by sijia on Stack Overflow
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Does the One Time Pad rely on confusion or diffusion?

From what I could research, XORing a random key adds confusion. But I do not undertand the rationale for that classification. Shannon's confusion is supposed to obscure the relationship between the ...

1 answer

C RSA key generation program

I'm trying to hone my skills in C as well as get a better understanding of RSA, so I took it upon myself to try and make my own generator. I've generated both base prime numbers, p and q, calculated ...

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Hardening of random number generators

Boxcryptor uses various CSPRNGs and apparently hashes the output using PBKDF2 to derive the final key. Even though the choice of PBKDF2 is probably not semantically correct (PBKDF2 is intended for ...

2 answers

Running a java program through command line

I am running a Java program with the following command: java -cp .:./* All the jar files are in the same directory. It works FINE! But what if I want to run it from a ...

2 answers | 8 hours ago by Luis Cruz on Stack Overflow
2 answers

pdftex driver of hyperref package doesn't work with utf-8 encoded .tex files

i use pdflatex to generate pdf files. my source files are all utf-8 encoded because of non-english characters. without \usepackage{hyperref} code, they can be compiled without any problem. but when i ...

2 answers | 9 hours ago by Lion on Stack Overflow
3 answers

Key size difference between AES and RSA

Can I say that 128 bit using AES provide more security than 1024 using RSA?

3 answers | 9 hours ago by BOB on Information Security
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Garbled or missing LaTeX math formulas in RMarkdown->PDF knitr-converted document

I'm using Rstudio to write an RMarkdown document that I turn into a PDF using MiKTeX on Windows through knitr and pandoc. LaTeX engine is xelatex. My .Rmd file YAML header: --- title: "My Title" ...

5 answers

What does “key with length of x bits” mean?

I'd like to know what it means to say "the cryptosystem C uses keys with a length of x bits". I do not understand what the bits length means... doesn't it depend on the encoding? The same word encodes ...

1 answer

determine strength of encryption from openssl config

I am a novice in the field of cryptography. Consider the openssl config param below. $openssl_config = array( "digest_alg" => "sha512", "private_key_bits" => ...

1 answers | 9 hours ago by Pratyush Deb on Stack Overflow
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Resizing a stargazer table in Knitr

I've put together a document using knitr and while most of the document looks fine, there's one regression table that's too wide to fit on a page without some alteration. The regression table is ...

1 answer

AES encryption/decryption from Android to server

I have one server and two clients. The server runs with Java and Jersey (Rest). One client is a Java client and the other is an Android client. I want to send message encrypted with AES. So I have ...

1 answers | 10 hours ago by BerHug on Stack Overflow
1 answer

HKDF entropy extraction

I collect entropy from the following sources: system_entropy = System provided crypto entropy stream (CryptGenRandom on Windows) user_entropy = User-provided entropy - in a form of a byte stream of ...

1 answers | 11 hours ago by Paya on Cryptography
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Is ?=SCROLL working in the *CDLaTeX Help* buffer for the math modify menu for you?

I use cdlatex mode in Emacs. It has a nice feature where if in a math environment, if you type a character and then a single quote, e.g., x', and pause for 1.5 seconds it brings up a *CDLaTeX Help* ...

11 hours ago by Joe on Stack Overflow
1 answer

Regeneration of SecretKey results in different key in java

I am trying to create an Encryption Program. However, The problem is when I am trying to Regenerate the SecretKey, I get different key which is not the same as the encryption key. Here is my code ...

1 answer

possible MITM attack against servers that used to support weak DH?

from reading the TLS 1.1 RFC, it looks like it would be possible to break a previously recorded TLS <1.2, 512-bit DHE ServerKeyExchange and then send it (unmodified, with the original, valid ...

1 answer

Encrypt-Mix-Encrypt: Full Diffusion?

I've read this paper about the encrypt-mix-encrypt mode for ciphers and was asking myself if this mode provides "full" diffusion. So if an attacker alters one bit of the ciphertext, how many bits ...

1 answer

How to prove that someone encrypted a specific (large) chunk of data

Alice encrypts her data with HER secret key. Then she sends the encrypted data to Bob who should encrypt it with HIS secret key. Caroline should then eventually get this double encrypted data. ...

1 answer

How to fix invalid key size when decrypting data in C# that was encrypted in php

I am trying to solve an encryption issue I am having between php and c#. I have encrypted data using the following php and openssl operation. $encrypt_method = "AES-256-CBC"; $secret_key = ...

1 answers | 12 hours ago by StewVanB on Stack Overflow
12 answers

Can a file contain its md5sum inside it?

Just wondering if it is possible to create a file which has its md5sum inside it along with other contents too.

12 answers | 13 hours ago by balki on Information Security
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