This tag is used for code review questions relating to cryptographic topics such as encryption/decryption and hashing.

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6
votes
3answers
445 views

Simple password encryption / decryption

I'm working on a simple data storing program for my senior year (Secondary School / Grade 12), and there is a user sign-in functionality I've decided to implement. The way I've done this is by storing ...
6
votes
0answers
41 views

Unlock codes for a mobile app [migrated]

This is for an Android (via Cordova/Phonegap) game project. My goal is to be able to provide a "promo code" that will allow anyone to unlock the game for free, but I want to limit each code to only ...
4
votes
1answer
71 views

Polyalphabetic cipher

I am trying to write the simplest to undestand code possible, each function has documentation and examples and I tried to use the best style possible. ...
2
votes
1answer
34 views

Optimizing mcrypt encryption class further

The following is a very simple implementation of an Encryption class using mcrypt whereby the functions encrypt and ...
5
votes
2answers
72 views

Secure password hashing implementation

I'm implementing a password hashing method for a website. The code below is part of the User class. Any pointers on what I could do better? ...
3
votes
2answers
160 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 ...
2
votes
1answer
82 views

Encryption/decryption of a string with a salt

I have a new job coming up soon and want to increase my PHP knowledge. This is my first attempt at creating and using a class. I just want to know if it's the correct way to do things. It's very ...
2
votes
0answers
52 views

BouncyCastle RSA Implementation

This is my implementation of 1024bit(can be changed) RSA. Is there anything I'm doing wrong? ...
6
votes
2answers
298 views

MD5 shuffling with a defined pattern of numbers

I've created a MD5 shuffler with a defined number pattern. Does this make sense? Will this make storing passwords more secure? Is it efficient? ...
4
votes
1answer
39 views

String encryption function in admin section

I have been using this function locally to encrypt strings for example a username. If the user successfully logged in, place the encrypted username into a ...
3
votes
1answer
135 views

BouncyCastle Rijndael 256 Implementation

I modified the implementation from this website to include a salt: ...
0
votes
1answer
78 views

Decrease file size of encrypted file

I am making a Cryptography application and I noticed that the encrypted file is approximately 2 times bigger because I am encoding the files in base64. Are there any file encodings that take less ...
2
votes
2answers
109 views

Change random methods without losing too much performance

I have a class in C# that uses a Random object to get a list of numbers randomized from an array of 1-25. Now what I need is improve this method to use ...
1
vote
0answers
116 views

Encrypt texts, with saved password using pycrypto

I have the code bellow, which is supposed to be used inside a larger program. Please see notes about the requirements below the code. ...
0
votes
1answer
133 views

256 bit AES encryption in Android

I am using the following code to encrypt a file in an SD card in Android: I want the code to be reviewed for: Security (prioritize this) Coding Style Performance ...
12
votes
1answer
170 views

Cryptographically-secure super-secret government message transaction machine

-Hello Agent. Are you on a secure line? -Yes, secured. -Good, in 30 seconds the launch codes will be in your e-mail's inbox. You now have the go. Are you ready for the package? ...
5
votes
2answers
107 views

How easy is it to crack this encryption algorithm?

When I was about 13 or 14 years old, I was a little interested in cryptography (which is, after all, an interesting field). I learnt quite a lot since that time (it has been about 8 years since then), ...
5
votes
1answer
53 views

Clarity of encryption class

I have recently gotten back into development and I am wondering if the script I have just created is clearly documented and easily understandable throughout each step. Is it easy to understand? ...
10
votes
2answers
71 views

Citadel's VisualEncrypt and VisualDecrypt

I was skimming through this paper out of boredom. On pages 5 and 6, the paper shows a simple encryption/decryption scheme that Citadel uses to obfuscate data. The algorithm basically XORs the next ...
6
votes
1answer
104 views

Secure password-hashing in Java

Here is an article on password hashing, along with an implementation. Is this code secure with number of iterations 10000, key length 256 and salt bytes 32? Is there a rule-of-thumb for key ...
4
votes
1answer
79 views

Simple password dictionary attack script

This is my simple Perl script implement password dictionary attacking, encryption algorithm SHA1 with different length. It takes 2 arguments as input: first argument is password dictionary file path, ...
4
votes
0answers
102 views

Password-hashing method in Java [closed]

There is an article on Crackstation where they show you how to hash a password correctly. I've implemented the Java version of it which is working fine, but is the method they use secure? ...
5
votes
1answer
96 views

Parallelizing scrypt key-derivation function

To review my use of multiprocessing, I don't think it is at all necessary to understand the algorithm, but it's the scrypt key-derivation function. This uses ...
2
votes
1answer
148 views

User name and password validation in a MVP application

In a WinForms application I'm doing the password validation as follows: When the user presses the OK button after entering username and password, an event will be fired and the listener in the ...
2
votes
1answer
52 views

Ensuring client IDs are unique

I'm writing a node.js application that involves handling clients based on their ID without any real way of confirming that the ID a client says it has is its actual ID. That is, it's possible for a ...
6
votes
3answers
717 views

Simple Caesar shifter in C#

I use these in a windows form with fun buttons, I wanted to see what the world thinks of my coding. This is something that I coded about 2-3 years ago, I did change some of the coding when I looked ...
3
votes
3answers
50 views

Keyfile Generator

This is a Java program that generates a random keyfile (for OTP, for example). ...
3
votes
1answer
83 views

Structure and style of Enigma Machine

I took a little time and wrote the following code to produce enigma encryption. I don't normally write code in C so I would like to get feedback on the way it has been structured and any issues a ...
6
votes
1answer
80 views

MCRYPT - are there any flaws or areas for improvement in this class?

I am working on a class for encryption to use on my site. I have read through many examples of these functions and would just like to clarify a few points I have read and check if this code is worthy. ...
7
votes
3answers
74 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 ...
7
votes
2answers
131 views

Dictionary brute force on DES encrypted passwords

For a school project I am tasked to decrypt DES passwords. I have sample code provided below and I want to know if this is the best method. Also should I code in error handling for the dictionary ...
4
votes
1answer
181 views

How to optimize this Playfair encryption?

For the implementation of the Playfair encryption I needed a custom struct called Cell. This is because I not only need an array of characters I also want to get Elements in a matrix based on their ...
2
votes
2answers
125 views

Cryptographic Extensions

I have created a small crypto extension and I want a deep review of it, such as possible fixes (for hidden problems) and tweaks... 1- Crypto.cs ...
11
votes
3answers
619 views

Enigma simulator performance

Here is my implementation of a simple 3 rotor Enigma machine in C++: ...
1
vote
1answer
110 views

How can this Encryption Class be more secure?

How secure is this encryption? Secondly, is there something I could do to "turn it up a notch" and make it 'more' secure? ...
4
votes
2answers
96 views

Cookie encryption library

Recently I needed to save session state in cookies, instead of server side. I looked around and didn't see anything similar, so I decided to write something to handle the encryption, decryption, and ...
6
votes
2answers
242 views

OpenSSL PBKDF2-HMAC-SHAx proof of concept

I have regrettably been away from C programming for a very long time, so I'd like to get a quick code review of a first proof of concept, before I get too far into adding capabilities, using the ...
10
votes
6answers
2k 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 ...
10
votes
2answers
170 views

Can this secure, random generator be improved?

This random generator uses cryptographically secure numbers/chars instead of Math.random(). The Javascript code with jQuery works well but I affect clean code ;) It ...
11
votes
2answers
644 views

Password hashing method

I am having some issue to use PHP5 password_hash() function. My server is not supporting it, so I am using a function to hash. Is this one secure? ...
7
votes
1answer
84 views

Embed MD5 digest in a directory path name

My boss needs me to embed the MD5 digest in a file path, but the problem is MD5 contains escape characters. I've already taught about a uc%duc%d... format, but it ...
6
votes
1answer
756 views

RC4 implementation in C

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6
votes
1answer
176 views

Encrypting a payload for transmission over HTTP. AES256 with PBKDF2

I've done some reading about implementing AES256 and deriving a key from a password. If I understand correctly: I want to generate a new salt (for the key) and a new IV (for the encrypted message) ...
3
votes
2answers
316 views

Using SQL with encryption

This is my first project I am doing in VB.NET, and also my first real programming project. There is sensitive data, so I am utilizing Microsoft's Encryption/Decryption class (...
4
votes
0answers
882 views

AES CTR mode using pycrypto

I've implemented CTR mode by myself (only decryption for now), using only AES built-in functions from pycrypto. It means that I'm not supposed to use mode=AES.MODE_CTR. However, I know that using ...
4
votes
1answer
820 views

Encrypt Using AES

I'm using Microsoft's example for encrypting/decripting a string. In their example, they are using Tripple DES. I'm trying to convert their code to use AES. The modified code, listed below, works. ...
8
votes
1answer
129 views

Python mint hashcash token

This is a Python program to mint a hashcash token, but my code is a lot slower than using a library. What is slowing my program down? It takes over 10 seconds to mint a 20-bit stamp, but using a ...
3
votes
1answer
726 views

Is this password hashing acceptable for a custom MembershipProvider?

I'm creating a custom MembershipProvider for an ASP.NET MVC5 application and am wanting to know if this code is acceptable for creating hashed and salted passwords. ...
2
votes
0answers
149 views

Sending signed email [closed]

Is this a good way to send a signed email message? It seems to me that a public key is a little too large to send as a email header. Should I be including the signature and key as a header field, or ...
6
votes
2answers
876 views

My API Keygen: Is it secure?

Below is an api key gen script for a cryptocurrency trading platform i am building. first it checks to see if a key exists in the db for the user id. if it does exist it displays the key. if it ...