Questions tagged [cryptography]

Questions relating to cryptographic topics such as encryption/decryption and hashing. (Not for use with trivial ciphers.)

29 questions with no upvoted or accepted answers
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Automatically encrypting text editor

I have written an automatically encrypting text editor (github link). The reasons that I wrote this program instead of using vim + gpg are: It's more convenient than vim + gpg (user only needs to ...
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78 views

SHA256 implemented in Rust

I just finished making an implementation of a SHA256 hashing function (https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf) in Rust and I was looking for some feedback. As far as I can tell it ...
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52 views

Atbash cipher in Ruby

I implemented my own spin on the Atbash cipher in Ruby: ...
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310 views

Verify OpenSSL RSA signature (PHP) with .NET (VB)

I would like to achieve something I believe is pretty standard: A) My VB.NET client (ideally targetting Framework 4.0) sends a text string to my Apache/PHP Server via an HTTPS POST request. B) My ...
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263 views

ECDH implementation in python (part 3)

After the first and second part, the primary feedback I got was to rename a lot of my variables as I used the same name for different local variables which is really confusing. I tried to hotfix that, ...
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336 views

Python2.7 Some xor fun

After doing the Cryptopals challanges, which I found scrolling through codereview, and finally being able to solve set1 challenge 6. I decided to have a little xor fun, and make an automated xor ...
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1k views

Encode object to JSON and encrypt with AES (with tests)

While the task at hand is relatively straightforward, it turned out AES in Go is a bit clunky so I was wondering if this seems right. Also, any tips on Go coding in general are more than welcome. <...
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2k views

Web API 2 - JWT with X509 certificate

I got my JWT generation working with X509 and wanted to ask if you would recommend any changes in respect to: Signing certificate storing / handling. Publishing for anonymous access public key ...
3
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0answers
280 views

Streamed encrypt then MAC construction

I've been porting python Keyczar to work under 2to3 conversion (Github). I wanted to consolidate its streaming AES encrypt/decrypt backend interface with its string decrypt/encrypt. So I wrote a new ...
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29 views

SHA-256 implementation in JS (core codes)

As told by experts, I am re-posting the code review request with the code. Brief Description: from outside sha256() will be called with parameter having UTF-16 character set. then after prepareData()...
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73 views

Custom mini cipher

I'm a 14year old and still learning. I know everyone says "don't roll your own crypto", however I decided I must make my own cipher in javascript as soon as I have enough knowledge. I started simple ...
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131 views

XXTEA encryption implemented in modern C++

At the company i work we have a system where an user is presented with a question and some alternatives to choose from. The question and answers are generated at runtime. In order to simplify the ...
2
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25 views

RC4 in Sinclair BASIC; Working around one-indexed arrays

This is a program written in Sinclair BASIC (48 BASIC) for the Sinclair ZX Spectrum. It uses a hardcoded key (null right now) as seen in the bottom and outputs a stream of integers generated with RC4. ...
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382 views

Python RSA/DSA File Cryptography, Key Generation, Key Protection

I have forked a previous version of my script, critiqued here: Generate public/private keys, encrypt, decrypt, sign, verify This program allows you to encrypt and decrypt raw files using RSA keys ...
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693 views

Hashing a SecureString in C#

In .NET, the SecureString type exists to prevent leaking secrets in memory. I want to create a hash from the contents of a SecureString, without putting the contents in memory in a place where I can't ...
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749 views

Wrapper/abstraction for encryption and decryption using OpenSSL

I am a beginner when it comes to cryptography and OpenSSL. I have written a short wrapper of some functions in OpenSSL as well as a test of this wrapper, copied below. Specifically, this code is ...
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183 views

Locally encrypt/decrypt credentials

I wrote some code to encrypt and decrypt some user credentials for services that a locally run application needs to work. I get a password from the user, use it to stretch a key via Scrypt, and then ...
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904 views

Converting [UInt32] -> [UInt8] -> [[UInt8]]

I am trying to speed up my current implementation of a function that converts [UInt32] to a [UInt8] which in turn is split up ...
2
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2k views

LockBox TwoFish string encryption and decryption

I'm using TurboPower LockBox for the first time, and using the TwoFish algorithm to first encrypt a password, and later retrieve the password by decrypting the generated hash. I would like to know ...
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193 views

T-SQL Totp (Rfc6238 SHA2_256) Implementation

Using my previous function as a base I've come up the following: ...
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365 views

Simple encryption with PHP 5.5

I want to do simple encryption using PHP 5.5. By “simple” I mean I want to use native PHP functions. I have created this code that works, can it be improved? It's to encrypt/decrypt strings and binary ...
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163 views

AES256 + HMACSHA256 'secretbox'

I aim to create a few primitives for creating AES256-then-HMACSHA256 secured session state through cookies. What I've considered: HMAC instead of plain sha to avoid hash extension attacks input ...
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188 views

RSA Encryption, improving programming practice and code quality?

This was my first go at any kind of encryption in any kind of programming aspect but my application needed some kind of RSA end encryption for my game packets. Uses RSA and diffihelman and runs off 3 ...
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620 views

KDF computation using CMAC with AES (as PRF) using Bouncy Castle C# library

Using bouncy castle .net implementation (version: 1.8.1.0), I am trying to create an encryption key from a known master key using a key derivation function. The NIST Publication 800-108 contains ...
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53 views

Unicode-friendly password generation

The following algorithm is meant to generate a password from a given set of characters, and a length. Is it biased or predictable in any way? And are graphemes the appropriate Unicode thing to use ...
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595 views

API with security through a private and public key

I want to make users login into an app. The code on my server serves a "token". This is based on a salt that is saved for each user, the login date, expDate and the ...
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562 views

Is this implementation of the ECIES cipher correct?

I downloaded source code of cryptosms and implemented the ECIES cipher in my work for Java mobile. I doubt validity of this step (full code of my method is below): ...
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A register of government decrees, authenticated with blockchain and public key cryptography (2)

This is a follow-up question to this question, having carried out some of the advise kindly provided by other users. The full repo is here, but I'll post the most important extracts below. ...
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146 views

XOR 256 Block Encrypting and Decrypting

I am quite new to Go but have found it to be very useful for my use case (game server). I have a routine that encrypts/decrypts the game packets which was written in C++ which can be seen here and ...