All Questions
Tagged with cryptography beginner
40
questions
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 ...
- 113
2
votes
1
answer
132
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 ...
- 189
4
votes
1
answer
179
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 ...
4
votes
2
answers
203
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 ...
2
votes
1
answer
1k
views
Python script to compress and encrypt a list of files/directories (tar + gpg)
I've tried, as practise, to write a Python 3 script which takes a list of paths to files/directories and compresses them with tar, before encrypting the resultant ...
- 21
3
votes
3
answers
161
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 ...
- 31
6
votes
2
answers
1k
views
Python 3 Vigenere Cipher
I'm still fairly new to Python and I'm trying to see if I've efficiently used modules, functions, etc or if there's another/easier way to do something.
This Python 3 Vigenere Cipher is a rebuild of a ...
- 247
7
votes
1
answer
315
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 ...
- 79
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 '...
- 139
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 ...
- 163
5
votes
1
answer
1k
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 ...
- 7,270
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 ...
- 213
5
votes
1
answer
72
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 ...
- 513
5
votes
1
answer
168
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
...
- 233
2
votes
1
answer
553
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.
...
- 141
4
votes
1
answer
395
views
HKDF and compare constant time in Rust
I have implemented HKDF in Rust, which passes all test vectors from RFC 5869, using HKDF with HMAC-SHA256. I also have a function to compare byte arrays in constant time, which I hope someone could ...
user159822
4
votes
1
answer
156
views
(Final)Simple Decryptor/Encryptor
This is my final version of my simpel Decrypter/Encryptor called Dencryptor. This is one of my first Python projects and I think it turned out pretty good. I am using a Caesar cipher right now and I ...
- 125
7
votes
1
answer
617
views
HMAC with SHA256/512 in Rust
I've tried as best I can, to implement HMAC as specified in the RFC 2104. This is also my first Rust project, so the chances that rookie mistakes have been made are high. Since I'm fairly new to the ...
user159822
4
votes
2
answers
201
views
File's encryption tool in terminal
I've created a wrapper for the SimpleCrypt library that allows to easily encrypt/decrypt a string.
The application is used this :
...
- 12.4k
2
votes
1
answer
559
views
Bash - script to encrypt pdf files using pdfencrypt
I wrote a small script to get around the issue when using pdfencrypt on the command line the password is always echoed as well as being saved to the 'history'.
<...
- 321
1
vote
1
answer
143
views
AES Java security
I am new to security and I was wondering if I can make my program better by changing or adding something to make it better/secure.
Should I use a keyGenerator? I have my doubts from my program output....
- 11
3
votes
1
answer
2k
views
Implementation of Ceaser's Cipher in Python
This is my implementation of a Ceaser's Cipher in Python using OOP principles. I'm looking for feedback for any code starting from the function build_shift_dict (...
- 475
1
vote
1
answer
856
views
Encrypting and decrypting strings using Caesar cipher
I was inspired by a solution in Think Python: How to Think Like a Computer Scientist. I structured mine (into two functions) according to it, and used the technique used in
...
2
votes
1
answer
1k
views
CUDA brute force 48 bit key
I have a cryptographic function with two 24 bit keys.
I have two blocks of input and two blocks of output, and want to brute force the keys using CUDA.
Overview:
The function is composed to two ...
user61924
1
vote
3
answers
3k
views
Encryption algorithm using CTR mode
I am using CTR mode (it is a cipher in itself) in this code. I just wanted to see what you thought about it before I finish it.
(Yes, I know that the plaintext length and key length must be highly ...
- 27
4
votes
3
answers
6k
views
Cipher decryption and encryption
I'm brand new to C# and I've started to make a cipher decryption program. The code works and runs fine, apart from the odd exception. I'm just looking for ways to improve my code and make more ...
- 41
7
votes
2
answers
17k
views
Simplified DES encryption
This is one of my first Python scripts and I was wondering if it meets the correct conventions. Also are there things that you would write different? I am looking for some good comments so I can start ...
- 95
10
votes
2
answers
371
views
Enigma machine simulator
As my first (keep that in mind!) Haskall program (full code at end) I've written a simple Enigma machine and would like feedback on the core code related to its stepping and encoding — stripped of ...
- 401
4
votes
1
answer
4k
views
Python mnemonic ↔ hex conversion (Bitcoin BIP39) - follow-up
Original question:
Python PBKDF2 using core modules
I'm looking for commentary on the following code, which converts from a hex seed to mnemonic (12 word phrase), and vice versa. It's for Bitcoin (...
- 193
10
votes
1
answer
3k
views
MD5 hash comparison for two folders
Using this page for a starting point into comparing MD5 hash values from files in two different folders, I've put something together that outputs either Copied if ...
- 351
6
votes
1
answer
1k
views
Basic cryptography algorithm
I wrote 2 classes in order to implement some basic cryptography algorithm. I tried to use some object-oriented concepts of C++. I'm a beginner, so any comment or suggestion is welcome.
First class: ...
- 177
10
votes
3
answers
4k
views
Brute force MD5 password checker
I'm trying to create a C# brute force MD5 password checker. If I run it with "test1" without MD5, it completes in 15 seconds. I would like to make it faster, but I'm a c# beginner, and don't know how ...
- 293
13
votes
4
answers
3k
views
FileScrambler, a command-line file encryption tool
I decided to try my hand at making an encryption utility, which I lovingly call "FileScrambler". FileScrambler allows the user to encrypt a file (a master-password list, personal diary, or whatever) ...
- 391
3
votes
2
answers
9k
views
Encryption with many algorithms using Crypto++
For the last few days I have been working on this code to develop a class that allow me to crypt a block of byte with many algorithme.
One block will be divided into three equal blocks and every ...
- 185
7
votes
3
answers
115
views
Encrypt and backup folder to email daily, when online
I have a backup script which should backup a folder and send it to email. This should be done once a day. As this is on my laptop which is not online 24/7 I need to check that I am online and can send ...
- 171
15
votes
6
answers
11k
views
Small one time pad encryption program
This one time pad encryption program I have written (basically just an XOR "encryption" program) seems to be working fine, compiling nicely (gcc -o ./OTP.c), and doing what it's supposed to. However I ...
- 253
8
votes
1
answer
584
views
RC4 in 8051 assembly optimization
I've been playing around with 8051 assembly lately and thought I would make a little project of implementing RC4, since it is pretty interesting and the algorithm doesn't seem too hard. Plus, taking <...
- 223
8
votes
2
answers
1k
views
Generating a tabula recta
I want an experienced Haskeller to critique my code and offer changes/suggestions (so I can learn the idioms of the language and culture around Haskell).
I've been using a Tabula Recta for my ...
- 235
5
votes
2
answers
3k
views
Encryption/decryption of data
I'm trying to work with some encryption/decryption of data. It was some hard work for me to get it working with some buffers and what not.
This is the code I came up with:
...
- 153