Questions tagged [cryptography]
Questions relating to cryptographic topics such as encryption/decryption and hashing. (Not for use with trivial ciphers.)
377
questions
2
votes
1answer
92 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 ...
5
votes
1answer
55 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
1answer
112 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
2answers
120 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
1answer
88 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
1answer
46 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 ...
1
vote
1answer
115 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 ...
2
votes
0answers
37 views
Difference distribution table for DES
This is my DDT (for DES) code.
I just wonder how to be more efficient...
I've just started cryptography and I'm not good enough.
...
11
votes
2answers
1k 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 ...
4
votes
2answers
52 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 ...
3
votes
0answers
56 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
1answer
66 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 ...
7
votes
0answers
46 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
2answers
109 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
0answers
49 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
1answer
204 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
0answers
38 views
1
vote
1answer
90 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
2answers
85 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:
<...
2
votes
0answers
16 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. ...
0
votes
1answer
151 views
Cryptographically secure token generation in C#
Is the following a cryptographically secure way to generate a random token? Does it have any of the predictability risks that are theoretically associated with using a GUID as a token?
...
11
votes
2answers
2k views
Employing 3DES algorithm in Java
I am making a project just for fun that employs the 3DES algorithm in Java. I was wondering if my algorithm looks secure. Is there any advice or feedback you could give me? Do I need to include an IV? ...
2
votes
1answer
42 views
Encrypts using AES GCM for data with limited visibility and long rest
This is the third iteration of my venture on creating an encryption/decryption solution. I asked a question here, which led to this question here, which led to this answer here, which led me to ...
1
vote
1answer
345 views
RSA wrapper written in Kotlin
I've written up a small wrapper for RSA and AES encryption in Kotlin, and I want to make sure I'm not making any glaring mistakes before use it. This is going on a small project with basically no ...
1
vote
1answer
49 views
Encrypts using AES with random initialization vector meant for data with limited visibility and then long rest
I've done some research, reviewed countless SO questions that appeared similar, leading me to endless rabbit holes.
My solution is working, but I don't like it. I want to create a random IV for AES ...
5
votes
2answers
136 views
Python AES-CBC implementation using AES-ECB
I am looking for ways to make this code more "pythonic" and any issues with my implementation. This was designed to solve Crytopal's Challenge 10. This challenge requires recreating the AES-CBC cipher ...
5
votes
1answer
40 views
High performance wrapper for CSPRNG arc4random(3)
This function is a wrapper for arc4random(3), a cryptographic pseudo-random number generator on macOS and BSDs, but you can also get it by installing ...
4
votes
1answer
872 views
Naïve RSA decryption in Python
I am making a code with basic RSA encryption/decryption. My professor wants me to speed up this function but it is already so simple and I am lost. Any ideas?
...
2
votes
0answers
100 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 ...
8
votes
3answers
183 views
Generate public/private keys, encrypt, decrypt, sign, verify
My program generates public private keys, encrypts, decrypts, signs and verifies, while using AES for the bulk of the data for speed, and encrypts the random key with RSA. Many operations were chosen ...
1
vote
1answer
130 views
Using encryption/hashing to create a secure login
I am creating a login for an encrypted chat application which retrieves login information from a MySQL database. I have got to the point where I feel pretty confident that (to the best of my knowledge)...
1
vote
1answer
67 views
Encrypt data to be send from service to service
I'm working with another company in a new application for my company. My job right now is to send on demand to the other company the data that they need, ciphering some of it.
I should point out that ...
2
votes
1answer
75 views
Crypto for a funny contest with friends
I am participating in a funny crypto contest with my friends. This time, we raised the bar quite a bit.
The code below is my take for the constraints we set.
Note that on my machine, the code works ...
3
votes
0answers
94 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 ...
6
votes
2answers
173 views
RSA c implementation
This is my first attempt to implement a crypto algorithm.
I am using C and gmp to interact with big numbers.
Here is my code; you can run it after having linked with the ...
5
votes
1answer
137 views
First encryption program
This is the first piece of code that I write that's not just an exercise but a full program I can actually run.
Features:
Generate random letter/number pairs for each "printable" ASCII character
...
2
votes
2answers
66 views
Checking hash and passwords with a wordlist, more efficient
I have done a small code in which with a wordlist (out68.lst) I get the passwords from the hashes in the file 'shadow3'.
...
10
votes
1answer
480 views
XTEA Block Cipher
Usually people recommend to never implement cryptographic algorithms yourself unless you are an expert in the field. This of course makes a lot of sense mainly because there are numerous things that ...
7
votes
1answer
139 views
Frequency Analysis & Chi-Squared Test
Following up on my implementation of Cryptopals Challenge 1, this is my solution to Challenge 3.
Single-byte XOR cipher The hex encoded string:
...
1
vote
1answer
56 views
Spring API that performs RSA encryption with exception handling [closed]
I'm creating a rest api using Spring which utilize javax.crypto as library to do some encryption stuff. While everything works well, I'm curious whether the error handling like this is acceptable or ...
1
vote
0answers
657 views
Secure password hashing implementation with salt and pepper
I share below my password hashing implementation with salt and pepper in C#, for your review and feedback. In my implementation methods like ValidatePassword(), ChangePassword() are in the user class.
...
2
votes
1answer
96 views
Vigenère decoder/encoder in Python (using matrix)
I made an encoder/decoder for the Vigenère cipher. This one is using a table, not the remainder technique. Please let me know what you think can be done to improve performance, etc.
...
-2
votes
2answers
111 views
Generate cryptographically strong random string of characters [closed]
The method below is returning a string of random characters using RNGCryptoServiceProvider. The return string result is built by ...
1
vote
2answers
300 views
Encryption scripts using the module cryptography
Its meant to password protect python scripts by using encryption
It should use os.urandom(40)'s output in hex as the salt. The kdf (cryptography.io) is using Scrypt ...
3
votes
2answers
119 views
JSafebox - Encrypted vault - 2nd drill
I am developing JSafebox, a portable safebox project written in Java.
A first review have been completed here.
The goal is to provide a secured environment where the user can browse encrypted files ...
10
votes
4answers
5k views
Encrypt a byte array
This code is a Frankenstein. I found ten examples done in ten different ways and my requirements were slightly different so even if they were reliable they weren't a copy and paste solution.
Encrypt ...
8
votes
2answers
170 views
Encrypted safebox
I am developing JSafebox, a portable safebox project written in Java. The goal is to provide a secured environment where the user can browse encrypted files without leaking data on the drive.
The ...
4
votes
1answer
390 views
Hash and check passwords in node.js using the native pbkdf2
I use the native crypto . I use the pbkdf2 and the randomBytes for salting, and the timingSafeEqual to check for the password validity when logging in.
I wrote the following functions, based on ...
7
votes
3answers
3k views
File encryption with password
I would like to have my C# cryptography code reviewed.
I programmed an application that encrypts files with a password (provided by the user). It basically functions as a password manager, on the ...
6
votes
2answers
131 views
OpenSSL AES GCM Convenience Wrapper in C
I wrote this code for inclusion in a repository of encryption code examples. The cryptographic primitives in use are required for compatibility with the other code samples.
It's been a long while ...
