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2
votes
1answer
133 views

Hash function with uniqueness guarantees and controllable entropy

Is there a class of hash functions that meets the following specs: Upper and lower bound can be specified Uniqueness is guaranteed as long as the input is between the upper and lower bounds Amount ...
28
votes
7answers
4k views

Is there any algorithm pattern to protect any content in the web to ensure I am the first one who created it?

A few years ago there was this hacker (don't remember who he was) that full disclosed a vulnerability in a given system, but to make sure nobody took credit for that, he created some kind of PGP key. ...
1
vote
1answer
306 views

Difference between reverse lookup tables and rainbow tables

Using Reverse Lookup Tables, you create a lookup table consisting of the password hash of user accounts. Then you use another table which consists of hashes with guessed passwords. Then you compare ...
0
votes
1answer
68 views

Does inserting/removing random characters in a string count as cryptography?

I'm making an iOS game. All developers need to determine whether their app uses cryptography or not. My game saves files in the Documents folder. They are .plist files representing dictionaries. They ...
2
votes
2answers
136 views

How faster could a dedicated chip do sequential squaring modulo operations to break a time crypto capsule?

I'm facing a very real problem and, sadly, I cannot find the answer on my own: I'm hitting my limit as a programmer because my hardware knowledge is not sufficiently advanced at all. It's an issue ...
2
votes
5answers
268 views

secure photos on server [closed]

I would like to hear advice from the more experienced developers. The project is now in the design stage. It's mobile application and a simple web application. Content is pictures, comments, personal ...
0
votes
2answers
257 views

Snapchat clone: How do I secure pre-downloaded notifications so that they cannot be opened outside of the app?

Say I'm making a snapchat clone app for Android and iOS. Let's say that I get a snapchat from Baz. I want to pre-download the audio for this snapchat. However, as the developer, I want to secure this ...
8
votes
5answers
604 views

Where to store the private key?

Say I want some parts of my software to be encrypted. For example, the credentials for a database, etc. I need to store those values somewhere, but doing so in cleartext would make it easy for an ...
0
votes
1answer
336 views

deciphering columnar transposition cipher

I am looking for an idea on how to decipher a columnar transposition cipher without knowing the key or the length of the key. When I take the cipher text as input to my algorithm I will guess the ...
33
votes
1answer
1k views

What are the advantages and disadvantages of cryptographically signing commits and tags in Git?

So someone peer reviewed my work, and he told me that I should always sign my commits and tags cryptographically. When asked why, he didn't know to explain it to me, and said "It's just a good thing ...
-1
votes
2answers
577 views

What is the best programming language to do crypto running time measurement? [closed]

I am trying to measure the running time of different crypto algorithm. e.g. how long it takes to encrypt/decrypt a block of plaintext. May I ask if C with OpenSSL is the best PL to do this?
1
vote
2answers
776 views

How to manage my private key for signing .NET assemblies?

I write open source .NET class libraries as a hobby and thought about signing them. I can get Visual Studio to generate me a password protected public/private key pair and save it as a .pfx file, but ...
1
vote
1answer
356 views

Are python's cryptographic modules good enough?

I mean, say you were writing professional grade software that would involve sensitive client information. (Take this in the context of me being an amateur programmer.) Would you use hlib and hmac? ...
1
vote
1answer
359 views

Using a random string to authenticate HMAC?

I am designing a simple webservice and want to use HMAC for authentication to the service. For the purpose of this question we have: a web service at example.com a secret key shared between a user ...
3
votes
4answers
524 views

Public-private key pair handling on a Windows ecosystem

I've been thinking about how to architect an infrastructure for one of our business applications with the following requirement: Data written by some user can only be read by that user and his ...
6
votes
5answers
5k views

Can I watch a SHA-256 do its magic visually? [closed]

Is there any possible way I can download a program, type in a message, and watch the program display visually what iterations are going on and what formula the character is being fed through all the ...
7
votes
1answer
3k views

Java Cryptography Extension

I was told that in order to support AES256 encryption inside my Java app that I would need the JCE with Unlimited Strength Jurisdiction Policy Files. I downloaded this from Oracle and unzipped it and ...
2
votes
1answer
284 views

What alogrithm is used on the smart cards for the DNSSEC Trusted Community Representatives?

I've been doing some reading about DNSSec and am interested in the algorithm that they chose to use when splitting the trusted key up between the 7 Trusted Community Representatives (TCR). I ...
0
votes
1answer
3k views

C programming in Windows 7 [closed]

Which is the best book and what are the best tools for C programming in Windows 7? Would using C in any way hinder me when it comes to using the Windows API as opposed to using C++ or C#? I would ...
2
votes
1answer
231 views

Book on network cryptographic protocols [closed]

I am looking for a book that describes in fair detail the most common network cryptographic protocols such as SSL, TLS, SSH, HTTPS, etc. I already have some books that cover the underlying ...
21
votes
4answers
3k views

Programmers' concerns about export restrictions from the United States

Which aspects do I need to consider when designing and publishing software that must meet the US export restrictions for cryptographic software? Wikipedia says that there are various categories which ...
4
votes
1answer
303 views

What was the earliest use of cryptographic tokens in URLs?

I was wondering: it now seems to be more and more common to see people/framework putting cryptographic tokens in the URLs their webapps are generating (to prevent quite effectively against quite some ...
5
votes
6answers
1k views

How can I prevent users from creating multiple accounts on a web site?

I'm building a site that needs to guarantee user reputation scores are accurate by preventing users from creating more than one account, at the cost of decreased user signups. So far, the only ...
7
votes
3answers
327 views

Using a standard localised data cryptography pattern with an ASP.NET MVC3 application

I have been given the task to rejuvenate an existing Human Resources application from Access into ASP.NET. This is a strictly internal application, and I have no problems developing it within our ...
1
vote
4answers
324 views

MD5 implementation notes

While going through RFC1321, I came across the following paragraph: This step uses a 64-element table T[1 ... 64] constructed from the sine function. Let T[i] denote the i-th element of the ...
4
votes
7answers
4k views

Generating every combination of a 32 character alpha numeric string?

Is it possible to generate every possible combination of a 32 character alpha numeric string? If so, how long would it take on today's fast computers? My lecturer at university said it's impossible, ...
2
votes
1answer
303 views

What do these symbols mean? I'm trying to understand them to make an app

What do the symbols ⊞ and ⊕ mean? I'm trying to understand them to make an app. It's on http://en.wikipedia.org/wiki/File:XXTEA.png
26
votes
10answers
5k views

What should web programmers know about cryptography?

Should programmers who build websites/web applications understand cryptography? I have no idea how most crypographic algorithms work, and I really don't understand the differences between ...
1
vote
4answers
188 views

I need a public cryptography system that works on small keys [closed]

I just need it to support signing and signature verification. I need it to have public and private keys that fit each in 16 bytes. The signature itself must fit 16 bytes. I don't really care about ...