Questions tagged [cryptography]
Questions relating to cryptographic topics such as encryption/decryption and hashing. (Not for use with trivial ciphers.)
503
questions
2
votes
2
answers
1k
views
Encrypt data before sending it to server in a way that makes it unreadable to anyone except the user who sent it
I don't have any experience in cryptography and I've written some crypto code that seem to be working, but I'm not sure if it safe and if the tools and methods I used are right.
Objective
Make it ...
2
votes
1
answer
116
views
Custom code for MD5 in js [closed]
I wanted to write my own code for md5 in javascript and learn its inner mechanics. (I know it is not trusted anymore, deprecated, ... but I'm just learning).
I didn't want to just copy the code that ...
3
votes
1
answer
76
views
Inversionless Lenstra ECM running way slower than it should
So I was coding Inversionless ECM using Prime Numbers: A computational perspective and when I finished and tried running my program it ran way, way slower than it is supposed to. I have no idea what I ...
3
votes
1
answer
1k
views
Crypto createCipheriv and createDecipheriv for authentication
I'm not an expert in authentication, so I want to make sure I have done everything right.
I am using crypto.createCipheriv and ...
2
votes
2
answers
135
views
Encrypting an AES key
This encryption class RSA encrypts an AES key and then when the encrypt method is called it decrypts the AES key and uses the key to encrypt the message and basically the same thing with the ...
3
votes
1
answer
678
views
Validate implementation of ECIES
I've created a basic implementation of ECIES (Elliptic Curve Integrated Encryption Scheme) based on http://www.secg.org/sec1-v2.pdf section 5.1.
...
2
votes
1
answer
160
views
Berlekamp–Massey Algorithm in Haskell
I was recently tasked to write an implementation of the Berlekamp–Massey algorithm (for GF2) from a given inductional proof and decided to fresh up on my Haskell, since converting a proof by induction ...
2
votes
0
answers
86
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 ...
2
votes
1
answer
2k
views
Java RSA / AES-GCM encryption utility
I wrote a utility class that has simple methods for:
En/decrypting data with 256-bit AES-GCM using a password
Generating RSA keypair
Saving RSA keypair and storing private key encrypted
En/decrypting ...
7
votes
1
answer
718
views
CypherVault - Command Line Password Manager
I have created a Python 3 password manager for API keys and social media passwords on local storage. The script is 500 lines and PEP8/PYLINT compliant, each definition contains a docstring and the ...
3
votes
1
answer
483
views
SHA256 javascript implementation
I implemented a sha256 hash function for javascript just for a practice and I want to know if my code needs more improvement. Please tell me which to simplify if there's any. Thanks.
Here is my code:
...
2
votes
2
answers
95
views
A better cryptography process
I am experimenting with cryptography and I was wondering if somebody has some suggestion how I could improve my code and methodology.
I want my process to generate more securely the cryptography ...
0
votes
1
answer
288
views
Cryptopals first challenge - hexadecimal to base64
I've just started the cryptopals-challenge, and now wanted to show my solution to the first challenge here:
...
4
votes
2
answers
253
views
Fleissner-Grille / Turning-Grille in Java
I've implemented the cryptographic method of the Fleissner-grille aka Turning-grille .
Here's the code:
...
2
votes
2
answers
77
views
Decrypt multiple 10Mb files with defined password
One operation of my Android project is to decrypt one file (chosen in a set of ~30 files for pagination1) of ~10 Mb each and I do this with the following:
...
1
vote
1
answer
714
views
Password hashing (PBKDF2) and RSA encrypt + AES 256 in Java
Here's what I could comprehend in C code:
Generates a key using PBKDF2
Generates an IV which is MD5 of PBKDF2 key in step #1
Does AES-256 encryption on customer-id - which is one of the output
RSA ...
7
votes
1
answer
282
views
Understanding RSA key generation and implementation in Java
Here is an attempt to leverage Java's BigInteger class to implement the RSA algorithm, as well as md5 and sha512 hashing functions to generate keys for what I hope to be strong cryptography. My prayer ...
7
votes
1
answer
100
views
Incremental, encrypted backups for git
I would appreciate any review of the following script I recently posted on GitHub (gitcrypto). Most notably, I would be interested in a review of the cryptographic aspects (I am not an expert in this ...
3
votes
1
answer
128
views
CliwPw - Yet Another Python3 Password Manager
I wrote a (very) simply Python3 password manager to familiarize myself with Sqlite3, and for fun. I am aware that there are already a variety of password managers out there, but I wanted something ...
13
votes
2
answers
2k
views
A randomized encryption program
I have just created an encryption program with a friend. I wanted to know if anyone here could give me back any feedback on it.
Here is how the program works:
Imagine you want to encrypt the word '...
0
votes
1
answer
255
views
SHA256 hash bruteforcer
I made a SHA256 hash bruteforcer as my first program in Rust. It's very specific to what I'm trying to bruteforce and I'll probably never find it.
I translated it from Python to make it faster, but ...
0
votes
1
answer
1k
views
Encrypt a file using Botan library
I need to build something that is not very complicated, but efficient. I don't have much time to debug.
I don't know if this method is strong enough to encrypt a data to be displayed in a Qr code.
...
16
votes
3
answers
3k
views
A Caesar cipher in Python3
This code basically just does a Caesar cipher on the contents of the variable "s" with a shift of 1.
Sorry if the comments on the code don't explain it well. I'm quite new to Python and I'm not very ...
13
votes
4
answers
4k
views
Fast symmetric key cryptography class
I am trying to build a fast cryptography algorithm. The algorithm works fine, but I am worried if there are any potential flaws that might make the algorithm vulnerable to any kind of attack. Here is ...
2
votes
0
answers
636
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 ...
4
votes
1
answer
734
views
Python Secure Implementation Of AES-256-CTR Using Cryptography.Hazmat
I've implemented a wrapper for AES 256 CTR mode using the cryptography.hazmat module, I am wondering if there are any vulnerabilities in my implementation, specifically about the counter and its ...
5
votes
1
answer
799
views
Encrypting credit card data
I need an encryption algorithm that would be secure enough to store credit card data. So it should be reasonably secure.
Here's what I've come up with. I'd appreciate any constructive criticism.
<...
1
vote
1
answer
116
views
Small service for hashing and validating passwords, using PBKDF2
As part of a larger authentication/authorization system, I've developed a small .NET Core 3.0 service for hashing passwords using PBKDF2 (with a salt) and validating passwords against a stored hash/...
-1
votes
3
answers
64
views
Implement state eraser for NIST DRBG and other crypto primitives using macro
As a spare-time personal project, I'm implementing a set of symmetric-key cryptographic primitives.
One thing I've left vacant for a long time, is the key/state eraser, which I decide to add right ...
4
votes
2
answers
542
views
C# Cryptography Interface
C# lacks a common off-the-shelf encryption and decryption interface for dependency injection. Nearly every codebase I've ever opened has a couple of extension methods for hashing strings and so on. ...
5
votes
1
answer
982
views
Educational implementation of SHA256 in Rust
A few weeks ago I decided to have a look at the Rust programming language. After a few standard exercises I chose to try to implement the SHA256 hashing algorithm, because why not.
The algorithm's ...
4
votes
1
answer
361
views
Data encryption / decryption on Node.js
I've implemented my first data encryption / decryption methods on Node.js.
Although it might look similar to hundreds of sample implementations available online, I'm curious to get a feedback.
I'm ...
3
votes
1
answer
124
views
kryptein cryptography package for Node.js
I have written a cryptography NPM package called kruptein. The code is also hosted on GitHub.
Having used multiple "best practices" with regards to key management, algorithm selection, key size, iv ...
7
votes
2
answers
1k
views
A simple implementation of the principle of RSA encryption
Inspired by a Numberphile video I made a little program that shows the principles of RSA encryption and decryption. To calculate the keys I used the explanation in this link: rsa public private key ...
3
votes
1
answer
138
views
Capsulation solution for byte arrays
In a part of the project, I had to implement a solution for encapsulation of byte arrays. We do use ssh and secure ports for socket connection but I was in need of an extra layer of protection against ...
5
votes
2
answers
139
views
PLINQ code analysis in terms of efficiency of cryptographic hashes generation
I have the following code that I wrote in order to find the correct password by generating hashes out of all possible combinations and comparing each of them with the target. I'm trying to make ...
1
vote
1
answer
158
views
Expose encrypted serial ID in Elixir
I'm working on a Phoenix/Absinthe application and I thought to expose encrypted sequential IDs instead of UUIDs since these are a bit shorter.
Encryption on Elixir/Erlang seems very hard, so I think I'...
3
votes
1
answer
135
views
A Tumbler, or a format-preserving-encryption shuffle
I wanted to implement a simple algorithm for encoding id of entries in a database to avoid:
Storing the UID (unique id) in the ...
2
votes
2
answers
183
views
Light Security Local-Machine Password Encryption
I have a program that makes a call to an SQL database. I cannot use SSH to connect to it (as far as I am aware) or any other more secure method, so Java's SQL connector was used. As the connection ...
11
votes
2
answers
2k
views
Implementation of the Jacobi Symbol in C
I am new to C programming and wrote the following algorithm for the calculation of the Jacobi Symbol. Though there are some faster versions of this algorithm available I am only looking for some ...
5
votes
2
answers
270
views
File encoder/decoder in Nim
I wrote a simple program to encode a local text file with password and decode it back. There is one text file and it is either encoded with a password or is in plain text.
I had a version in Python ...
4
votes
0
answers
165
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 ...
4
votes
1
answer
110
views
PRBHA-10: A hashing algorithm in Python
So I've been working on a simple little hashing algorithm for Python that I like to call PRBHA-10 for short, or Pseudo-Random-Based Hash Algorithm. This is a hash algorithm in Python that is meant to ...
9
votes
1
answer
93
views
Fun crypto problem: Exploiting a vulnerable encryption scheme with Python
I came across a question asked here and here on the Crypto Stack Exchange site, and decided to analyze it as a kind of case study. To demonstrate the concept, I wrote a short python script depicting ...
7
votes
2
answers
892
views
Finding collisions of the first few bits of a SHA-1 hash
My objective is to find a hash collision of my modified hash function. Assuming my modified hash only outputs the first 36 bits of SHA-1. As we know, SHA-1 is a 160-bit hash value, hence, we only need ...
3
votes
1
answer
683
views
File Encryption using pynacl
I need a rather simple file encryptor/decryptor in Python, after some research, I decided to use tye pynacl library reading the file in blocks, writing them back out, and then at the end using Blake2b ...
15
votes
1
answer
337
views
Security audit of open-source, RSA Blind Signature library
I've just published a small library implementing the RSA Blind Signature process.
Here's the GitHub repo!
I needed something portable, and easy enough to use that I could ask other people to ...
3
votes
0
answers
77
views
Atbash cipher in Ruby
I implemented my own spin on the Atbash cipher in Ruby:
...
0
votes
1
answer
110
views
employing AES algorithm in Java
I have employed an AES algorithm in order to encrypt files within a GUI. I was wondering if my algorithm is secure. Could I change anything to improve it? Is my IV secure and is it producing different ...
4
votes
2
answers
605
views
F# wrapper to generate SHA256 signature for a file
I've created the following module to allow me to generate a SHA256 signature for a file. (In real life this is used to verify an image file hasn't been amended). The cut down code looks like this:
<...