Questions relating to cryptographic topics such as encryption/decryption and hashing. (Not for use with trivial ciphers.)
3
votes
1answer
84 views
“Cryptographic” hash function
I don't know much about the design of cryptographic hash functions but despite that I made an attempt for the sake of learning. This is what I got:
...
2
votes
1answer
66 views
Need help to make a more secure AES class
I've been working on my first "big" project in java, an AES encryption and decryption class, it's now working but i don't know how to improve my code. Also i'm not the best in security and I have no ...
0
votes
0answers
33 views
Elliptic Curve Digital Signature
I am trying to make a simple signing algorithm using known standards; I used elliptic-curve in this case to make key-size small but still secure.
I appreciate all comments, and especially if you see ...
8
votes
1answer
151 views
Secure client-side encryption of user content
I am working on a pet project of mine which I've recently revived after a year long hiatus. The application is a note-taking application with client-side encryption. If you need an analogy think ...
3
votes
0answers
343 views
Making AES encryption in Go just a little easier
AES encryption in Go is already pretty simple, Gencrypt is a package that acts as a wrapper around Go's standard packages used for AES encryption to make it even more simple.
https://gitlab.com/...
0
votes
0answers
21 views
cryptography routine for stream data
I have code that was taken from a C++ project, I have implemented it in Go but with this line by line re-code comes a few non-optimized parts. Being an encryption routine for incoming and outgoing ...
1
vote
4answers
76 views
Java class to compute and get a MD5 hash as a string
Here is my class file to compute MD5 hashes on a file. I wanted to be able to easily calculate them without having to create a lot of overhead in the code using the class.
Can anyone tell me a list ...
3
votes
1answer
59 views
One time key for authentication
In a recent project I was to create a web service that would be consumed by another application. One of the requirements was to have a key in the service that authenticated the request as valid. But ...
1
vote
1answer
61 views
Vector-based Null Cipher
Continuing with my series of cipher programs, I hastily wrote a null cipher program, and I was wondering how it could be improved:
...
1
vote
1answer
70 views
Split string into “n” lengths with padding
I quickly wrote a short program to split a string into \$n\$ lengths with variable-character padding:
...
3
votes
0answers
15 views
Symmetric decryption with javax.crypto
I'm trying to determine if this code could be a memory hog with huge files. Can anyone tell me if there is anything I can do to make this more memory efficient, or is this how java.crypto works?
<...
2
votes
0answers
42 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 ...
7
votes
1answer
48 views
Securing a file encryption(ECIES) protocol using Scrypt + Inferno
I'm evaluating the security level of a file encryption app, which implements Scrypt and Inferno, in an ECIES context. The encrypted files are either stored on the user's PC/laptop, either sent with ...
4
votes
0answers
41 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.
<...
1
vote
1answer
59 views
Decrypting single byte XOR encryption
The code along with the utils module is also at github. If you'd also have any advice on how the whole crate is structured I'd love to hear it. :)
...
4
votes
0answers
38 views
ECDSA for Mathematica
The code below contains functions related to ECDSA (Elliptic Curve Digital Signature Algorithm) with standard parameters secp256k1. The implementation is based on ...
2
votes
1answer
59 views
Encrypting a user's file with a key that isn't stored but only known by the user
I want to make some kind of file vault. I want to store encrypted files in a MySQL table, and the key to encrypt/decrypt them is never stored but only known to the user (that's the goal, anyway).
The ...
-2
votes
1answer
60 views
Symmetric cipher [closed]
Can someone please review this algo and say if it has some weak places and/or what kind of algo is this (caesar, block etc)?
...
2
votes
0answers
51 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 ...
3
votes
1answer
98 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 (...
1
vote
1answer
135 views
0
votes
1answer
109 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
1answer
138 views
Encryption functions intended for production
I want to know if these encryption functions are ok for a live production application. Based on resources here and here and here I have put together these three functions.
Purpose
This code is for a ...
5
votes
1answer
128 views
AES Encryption/Decryption
Where I currently work I'm tasked with writing a good encryption and decryption code which will have DEK as well as KEK. Haven't started on KEK yet. I have already told them, that we need expert help, ...
5
votes
1answer
129 views
Using SHA-512 for encryption/decryption
It occurred to me that if SHA2 can be used to derive keys from passwords, then it might as well be good enough to generate random data that can be xored with a plaintext to encrypt and the other way ...
2
votes
3answers
333 views
Implement Transposition cipher in c++
I try to implement the encryption by Columnar transposition.
Input: key_secret and Text_to_encrypt, both of them are in lower.
Output: encrypted_text.
The code works fine but I have some questions:
...
2
votes
2answers
117 views
Simple ActiveRecord attributes encryption in Rails 5+
The task at hand was to ensure that certain columns in the database are encrypted in case the database data is stolen. I have a feeling that a lot can be improved here (naming, DSL, encapsulations) ...
2
votes
1answer
309 views
Signing a String using an identity and trust from a PKCS #12 Bundle
One of the requirements of a third-party SDK I am integrating with is to sign an identifier string with the identity from a p12 certificate. This code loads a p12 certificate from the application's ...
2
votes
1answer
855 views
AES-128 Encryption/Decryption of NSData
I recently found an Objective-C extension on NSData that encodes and decodes data with AES-128. I made an attempt to port this code to Swift 2.2:
NSData+AES.swift
...
0
votes
0answers
63 views
Hashing passwords with crypto in Node.js
Going through my old files today, I found this code which I wrote a year ago after being asked by my professor to create a "secure" encryption, decryption and password hashing functions.
...
3
votes
2answers
122 views
DIY String Encryption
I was asked to make a String encryption utility without using encryption API. I basically had to come up with my own encryption methodology! the program was to be able to encrypt a string and decrypt ...
2
votes
2answers
154 views
String Encryption
I was asked to make a String encryption utility without using encryption API
I basically had to come up with my own ecryption methodology! the program was to be able to encrypt a string and decrypt a ...
3
votes
2answers
73 views
AES class security
I am using the AES class (which I think I got from another post on Stack Overflow) for encrypting strings to a database. How robust and secure (would it be easy to break) is this class? Is there any ...
2
votes
3answers
107 views
String hash generator
There is a lot of code duplication because it generates hashes using multiple cryptographic hash algorithms.
How can I improve this code?
...
2
votes
2answers
67 views
Intel® TinyCrypt: AES-128/CTR to encryption/decryption of 2D arrays
I need to encrypt/decrypt 2D arrays (double pointers) using AES-128/CTR using Intel TinyCrypt (written in C). The following are two helper methods to simplify the library usage. Any comments would be ...
3
votes
0answers
212 views
Generating public/private RSA key pair programmatically, using it for JWTs
In my app I'm using JSON Web Tokens for authentication purposes, using the pyjwt library. Instead of using static keys and/or worrying about key distribution, the server generates a public/private key ...
7
votes
1answer
91 views
Steganography with AES encryption
I created a small program that hides arbitrary files in png images using steganography - it encodes the files in the two least significant bits of every channel, so using a 4-channel png we can encode ...
1
vote
0answers
41 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 ...
8
votes
3answers
209 views
Implementing AES encryption in Java
I'm not a security expert, but while checking over our AES implementation for our flagship product, I've noticed some strange things, like the output length having a relation with the input length and ...
4
votes
1answer
143 views
PyCrypto AES-256 CTR wrapper secure for public use?
I have tried to write a more user-friendly AES CTR wrapper with PyCrypto, but I'm not sure if it's safe enough. I mean, by default there is IV=1 for CTR and in documentation it's said that IV is ...
1
vote
1answer
175 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 ...
0
votes
1answer
85 views
Effective ways to find partial sha1 collision
I need to find 2 different string and compare their hash value. Both string must contain "abc". I looking for the first eight character that are the same and stop. I have been running for more than 24 ...
11
votes
1answer
396 views
Secure way to store and load password in app config
I am trying to figure out a good way to store and load a password in the application configuration of my C# application.
To achieve this I use the BouncyCastle library and the DPAPI from Windows.
To ...
1
vote
0answers
132 views
Simple Java Encryption/Decryption
I am a beginner at Java programming, and I'm always curious about how to make code more efficient or learn what I am doing wrong. I just started learning about cryptography, and this is a simple ...
12
votes
1answer
230 views
.NET 4.5 licensing subsystem using RSA-4096 strong name key, SHA256 signed XML, and assembly signature enforcing
Abstract
For the past week I have been looking at taking advantage of the .NET 4.5 improvements to code signing and XML signing to produce a licensing subsystem I can use to license my own products. ...
3
votes
1answer
31 views
AES Wrap function
This code is supposed to implement RFC 3394 which also described in this PDF at page 11.
Are there any weak places or formatting issues in attached source? Or maybe some places are not explicit ...
1
vote
2answers
120 views
File-encryption utility application
I made a simple file-encryption utility application for a little school project.
I'm really interested in cryptography, and tried my best while making it.
Can you see it, and give me feedback?
The ...
7
votes
1answer
1k views
Encrypting strings in Golang
This is a an example application for testing some encryption and decryption functions in Golang. The functions encryptString(), ...
0
votes
1answer
199 views
Implementation of authenticated encryption
My application needs to implement authenticated encryption using C#. There is a .NET class called encryptAndAuthenticate, but it is only supported on windows 8 or ...
1
vote
2answers
252 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 ...
