Questions tagged [cryptography]

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

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Encrypt a String using AES in CBC mode

Your opinion interests me regarding this program. This program encrypts a text message using the AES256 algorithm and CBC. It allows the creation of an encrypted message that contains: The salt used ...
b210205's user avatar
  • 33
3 votes
2 answers
202 views

Encrypting large files using RSA and AES-256-CBC-HMAC-SHA384

I developed an application that stores large files. Those files are stored in plain text. Now the project owner wants those files be encrypted on storage, he wants confidentiality, integrity, and ...
Jesús López's user avatar
11 votes
3 answers
2k views

SHA-256 Implementation

I've been working on a byte-oriented SHA-256 implementation for educational purposes. I then tested it using the NIST CAVP tests found here. All tests pass but I would appreciate some feedback from a ...
dRevan25's user avatar
  • 113
3 votes
1 answer
111 views

Encrypted websocket chat using AES (EAX) and RSA for signing

For learning purposes and because it really interests me I am trying to get a better understanding of cryptography by trying to make my own basic secure chat-application. I posted a first version of ...
O'Niel's user avatar
  • 197
3 votes
1 answer
185 views

Encryption implementation for websocket chat (RSA + AES)

For learning purposes I am trying to make a encrypted chat in Python using Websockets. I am using AES and RSA to make it safe. The idea of the chat is that it's a group-chat. Users can join a chat by ...
O'Niel's user avatar
  • 197
2 votes
1 answer
74 views

An implementation of encryption cascade

I'm looking for feedback on some source code, I have everything documented and have corrected some errors. Looking to see what I did correctly, incorrectly, and what can be improved. ...
bismofunyuns's user avatar
3 votes
1 answer
70 views

Implementation of aes-cbc-hmac combined with xchacha20-poly1305

I’m using two ciphers in this code that are in this order- encrypt plain text with xchacha20-poly1305 then encrypt the resulting ciphertext with aes-cbc-blake2b hmac. I was told elsewhere rather than ...
bismofunyuns's user avatar
1 vote
1 answer
90 views

Password database: saving and loading encrypted files

I'm writing a password manager application, mostly with the goal of learning about proper handling of encryption. Here is my code responsible for encrypting/decrypting passwords and loading to/from ...
gazoh's user avatar
  • 3,249
2 votes
2 answers
156 views

AES-GCM and AES-CBC-HMAC encryption methods

Looking for code reviews of these two encryption methods. And if GCM is better or worse than CBC with HMAC. AES-GCM ...
Bismofunyuns's user avatar
6 votes
3 answers
146 views

Idiomatic and performant file hashing

I've written a small program that will accept a directory path and recursively calculate the MD5 hash of each file. ...
etchesketch's user avatar
2 votes
1 answer
124 views

Password recognition with cryptography

Since I only just learnt about this, I wanted some advice on better practices I can use when it comes to cryptography. Still learning python and hoping I can get this 'hashing' and 'salting' thing in ...
Beginner's user avatar
  • 189
-3 votes
1 answer
225 views

Simplistic C program to encrypt and decrypt a string [closed]

I wanted to improve a crypter from internet. I found it poor and modified it. Do you like it? ...
      ogyrehlosiash's user avatar
2 votes
1 answer
131 views

Generate a valid private key from public key

Given a public key, I want to generate a corresponding private key. I know this will take at least decades or centuries on average to achieve. I am wanting to increase performance as my current code ...
hflvegmnc's user avatar
2 votes
0 answers
160 views

Point addition on secp256k1. Exploring other alternatives for practical purposes

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Knm's user avatar
  • 21
0 votes
1 answer
2k views

Encrypt and decrypt text using 256-bit AES-GCM

I'm working on building an encrypt/decrypt feature using AES, and a fixed AES 256-bit key size. I have decided on using AES-GCM, as it seems the most performant and secure. I would like to know ...
Jake Nelson's user avatar
5 votes
2 answers
2k views

SHA-256 Hash with a short string length in javascript

I think I've found a way to somewhat "compress" the length of a SHA-256 hash. I am doing some addition, so I wanted to know whether an approach like this is secure or not. ...
rfl890's user avatar
  • 101
5 votes
1 answer
196 views

Hybrid encryption library for text/image encryption (additional feature implementation)

I am coding a hybrid encryption library that utilises AES and RSA to encrypt text/images, The library is working fine however I am wondering if I can make any improvements to it. I have included ...
Vey's user avatar
  • 51
2 votes
1 answer
173 views

An evolutionary algorithm written in Java to crack an XOR cipher

Alright. So TryHackme is a website that tries to teach hacking with hands on labs. They have a room called JVM Reverse Engineering where the user gets to reverse engineer Java apps, and in particular ...
Aleksey's user avatar
  • 173
8 votes
1 answer
491 views

Improving the speed of an MD5 implementation from scratch in C++

I wrote an implementation of the MD5 hashing algorithm from scratch in C++, following the original RFC: https://www.ietf.org/rfc/rfc1321.txt . It works as expected, and the outputs match all the test ...
Prashant Sinha's user avatar
4 votes
0 answers
123 views

Securely generate Token for authentication

In my experience i had the need that some application (both desktop and web) can excange data to authenticate users (even if the data for authenticating users are not reacheable form desktop ...
Skary's user avatar
  • 248
1 vote
1 answer
56 views

Random ladder for public-key encryption

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Pierre Abbat's user avatar
3 votes
1 answer
197 views

My Encryption Decryption Algorithm

I have been trying for so long to code an encryption/decryption algorithm using the modulus operator. Basically my code does a basic mathematical operation on given text and key then do a modulus 255 ...
Izzy Kiefer's user avatar
1 vote
0 answers
9k views

Simple AES encrypt/decrypt methods for .NET 6 and .NET Framework

I wrote some AES encryption/decryption methods with the following requirements: Inputs should be easy-to-use strings. Something encrypted in a .NET 6 app using these methods should be able to be ...
Rick Davin's user avatar
  • 6,277
0 votes
2 answers
2k views

AES GCM C++ implementation

I have written a C++ program that uses the Crypto++ library to encrypt files using AES-256Bit (in GCM mode). I am planning to eventually have the program store the keys for the files in a file e.g. ...
zero's user avatar
  • 11
3 votes
2 answers
735 views

Encryption algorithm for chat app

I'm working on a CLI chat app using Python and I've coded this encryption algorithm. I used hybrid encryption. This uses an AES key as the shared key for encryption and decryption and RSA to encrypt ...
Ahmed's user avatar
  • 31
3 votes
0 answers
328 views

Simple Merkle Tree

Discussion I just started learning about Merkle Trees and wanted to get some practice by attempting to implement a very simple Merkle Tree. The constructor for the tree takes some type of hash ...
Jae Bradley's user avatar
  • 1,845
0 votes
2 answers
916 views

Encryption and Decryption in C

I have written a program in C, which encrypts and decrypts a c-styled string (const char *) and print the result to stdout. It ...
Darth-CodeX's user avatar
5 votes
1 answer
1k views

Rijndael Cipher in C++ (128bit AES)

I am a hobbyist and do not work in the industry, but I do have an interest in programming an cryptography. I decided to have a go at writing a 128bit implementation of AES in C++. This is my first ...
WireInTheGhost's user avatar
3 votes
0 answers
99 views

Arduino portenta H7 compatible message encryption and decryption

I am looking to build a message encryption/decription method that would allow messages to be encrypted in a timely fashion on board an Arduino Portenta H7, using as much of the onboard hardware ...
L Selter's user avatar
  • 131
2 votes
0 answers
68 views

Simple CLI File Encryption

This program is designed to work on the command line by piping stdin to stdout and encrypting or decrypting the input using a symmetric key. Any suggestions for improvement would be greatly ...
muckypops's user avatar
4 votes
0 answers
126 views

RC4 stream cipher in ARM Assembly

Below is a complete implementation of RC4 in ARM assembly. Unit tests pass, including comparison to C implementation and to published test vectors. I'm appreciative of all feedback, comments (things ...
SRobertJames's user avatar
1 vote
1 answer
553 views

How do I make my program that creates RSA keys and encrypts and decrypts a file more secure

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The Masked Rebel's user avatar
1 vote
1 answer
2k views

.Net BouncyCastle - PKCS#3, PKCS#8 & PKCS#10 Generation as base64

Reaserching BouncyCastle for C# is not for the faint of heart. After navigating an ocean of Java dead ends, I have arrived at the following code. I believe it's very useful for someone who wants to ...
suchislife's user avatar
4 votes
5 answers
6k views

C++ AES Encryption Class

I am working with OpenSSL and writing an AES256 encryption module. My knowledge of cybersecurity is not vast and I would like to know whether there are any obvious holes I'm leaving. The intent is for ...
kich's user avatar
  • 41
2 votes
1 answer
3k views

Python 3 Playfair cipher encrypter and decrypter

I have written a Python 3 program that can encrypt and decrypt Playfair cipher, though I know it has been implemented countless times, none of the scripts I have seen so far(e.g. https://codegolf....
Ξένη Γήινος's user avatar
4 votes
1 answer
173 views

Enigma Implementation by Python newbie

I want to learn Python, so I ported a C# Enigma implementation of mine. It got UnitTests and is running. I'm looking for a review, telling me, where I don't know best practices, where I break naming ...
Professore Saltzman's user avatar
4 votes
2 answers
198 views

Enigma Implementation by JAVA newbie

I want to learn Java, so I ported a C# Enigma implementation of mine. It got UnitTests and is running. I'm looking for a review, telling me, where I don't know best practices, where I break naming ...
Professore Saltzman's user avatar
4 votes
1 answer
291 views

Cryptographic hashing class using OpenSSL's EVP interface

I have written a cryptographic hashing class named Ccksum::DigestHasher that allows the caller to select a hashing algorithm by name via OpenSSL's EVP interface. ...
user avatar
0 votes
1 answer
274 views

Encryption/Decryption algorithm #3

This is a follow up question to Encryption/Decryption algorithm #2 and Encryption/Decryption algorithm. In my last question, in @Reinderien's answer, he added this line ...
Have a nice day's user avatar
2 votes
1 answer
145 views

Encryption/Decryption algorithm #2

This is a follow-up question to this one. I have tried to implement all the recommended things in the answers (except commenting, and not being OS specific). Again, if you see anything that needs ...
Have a nice day's user avatar
3 votes
3 answers
158 views

Creating a class and calling it from other .py files

My objective with this code was to create a class and call it from other .py files. The code itself is working, but I would like to know what could be improved or be better implemented. I wrote ...
zaratabata's user avatar
5 votes
1 answer
3k views

Login system using bcrypt and MySQL, to be used for any future projects

Main function will ask what the user wants to do. LoginSystem class will handle the sign up and login process as well with the checking if password is right. passwordHashing will use bcrpyt to salt ...
drakebakincake's user avatar
1 vote
1 answer
3k views

Encrypted text - C# SHA256, implementation

I have a C# application which needs to encrypt string and save the key as a hash. The key is saved as a hash to check the right key has been input before trying to decrypt the message. First, I have ...
RemarkLima's user avatar
5 votes
3 answers
1k views

Caesar Cipher Encryption / Decryption in Python

I'm trying to write a Python program to predict the most likely substitution for a Caesar cipher. I managed to get it working, but it just seems very clunky and slow, especially because I need to ...
tommy2111111111's user avatar
2 votes
2 answers
191 views

Encrypting/decrypting messages in java

I am trying to implement message encryption/decryption with password in java. Here is the code I'm using: ...
user avatar
3 votes
2 answers
141 views

Correct implementation of encryption function

I wrote a simple encryption function that uses argon2d as the KDF and XChaCha20-Poly1305 as the AEAD. Since it is very easy to not get things right when dealing with encryption, I would appreciate if ...
Bernardo1r's user avatar
6 votes
2 answers
3k views

AES implementation in python

For educational purposes, I have implemented the AES block cipher in python. I decided to follow the interface for block cipher modules as defined in PEP 272. The implementation consists of two python ...
Aemyl's user avatar
  • 690
3 votes
2 answers
1k views

Encryption/Decryption between Python and Node JS

I have created a Python & Node JS encryption/decryption AES 256-CFB. The point of this little project is that I will encrypt a special URL with Python covered with base64 & URL encoding and ...
PythonNewbie's user avatar
3 votes
0 answers
85 views

Implement kleptography in Python

I'm new here, therefore I hope to be clear in this question. Firstly, I want to underline that I'm not a programmer, and I attended only a beginner course in Python, but I like to solve problems ...
Davide Motta's user avatar
3 votes
1 answer
486 views

Very simple encryption API

I need an encryption system with a super simple API. I'd prefer something as simple as the following. The output should also be browser-friendly and ideally url-friendly. ...
hanshenrik's user avatar

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