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Questions tagged [custom-scheme]

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173
votes
12answers
23k views

Why is it wrong to *implement* myself a known, published, widely believed to be secure crypto algorithm?

I know the general advice that we should never design¹ a cryptographic algorithm. It has been talked about very extensively on this site and on the websites of professionals of such caliber as Bruce ...
8
votes
4answers
208 views

How much security expertise does a general application programmer need to develop software ethically? [closed]

I am curious about this. I saw this thread: Why shouldn't we roll our own? and this answer: https://security.stackexchange.com/a/18198/144241 which had on it this comment, which had the second ...
2
votes
1answer
116 views

Slow Hashing Without a Salt?

I'm trying to design a security scheme that involves a shared secret but isn't a traditional account password situation. The server would store a set of "keys", each of which has a blob of data ...
0
votes
1answer
203 views

What is the name of this token-authentication scheme?

I'm working on a specific security design. When reading it, it looks like some form of OATH but I'm not sure which kind. The scheme is as follows: The client authenticates through a web-portal (...
3
votes
1answer
98 views

Is this a valid secure cookie scheme?

I have a scheme for a cookie with high-level confidentiality of information. The information to be hidden from the client is the expiration time of the cookie. I am wondering what insecurities i am ...
0
votes
1answer
59 views

Does this authentication scheme exist?

For an IoT project I've defined a simple security schema. Does this already exsist and if so, how is it called? Definition: There is one root key. With every key, a child key can be generated....
0
votes
3answers
120 views

Double-hashing authentication scheme

Rate my authentication scheme? (This feels simple enough to be a duplicate, but it's really hard to search for these types of questions. Sorry if it is a duplicate.) When a password is set, it's ...
2
votes
2answers
117 views

Simple-to-implement ad-hoc password validation scheme

I'm writing a level for a game in which the player has an advantage if they know a password. I want it to be infeasible to find the password from looking at the level's source code. The problem is ...
-4
votes
4answers
626 views

Roll your own encryption - with a twist

I am familiar with Schneier's Law: Any person can invent a security system so clever that he or she can't imagine a way of breaking it. I have read the many posts on this exchange littered with ...
2
votes
0answers
36 views

Distributed Shared Secret for RNG that only Distributor knows?

For one of my projects I want to create a way to sync up all participants' RNG with a seed where each participant does not know the seed of the RNG but also in a way that minimizes the number of times ...
1
vote
1answer
290 views

Is This DIY Password Authentication Scheme Acceptable?

This is mostly a thought experiment for client/server communication, and I want to know the flaws. When a user account is created (with U as the username and P as the password,) I generate a random ...
6
votes
2answers
725 views

What are the weaknesses of my authentication scheme?

So, recently, after going through some infosec training (FutureLearn's Introduction to Cyber Security, which I heavily recommend as well-explained newbie material), I decided to take the plunge and ...
1
vote
1answer
150 views

is this data encryption scheme viable?

My goal is to be able to encrypt the data so that no one would be able to make use of it if it was stolen. User data - the one that will be encrypted - can be any type of data Data encryption key - ...
3
votes
1answer
863 views

What is this QR code authentication scheme called?

What is this pattern for mobile authentication called? It's more convenient than entering complex password on mobile phone, and I wanted to read about it more A user is authenticated within webapp ...
0
votes
1answer
4k views

Where can I find a list of Indicators of Compromise (IOC) conditions?

OpenIOC.org has several schemas defining Indicators of Compromise. The Schema is defined here: http://schemas.mandiant.com/2010/ioc/ioc.xsd While under IndicatorItemContext/search says it is xs:...
3
votes
1answer
519 views

Are there any uses of having a non-deterministic salt value for hashes?

So I've been toying with the idea of having non-deterministic salt values for hashes. Let me explain what I mean: Basically, I applied some properties from Bitcoin including a "difficulty" (ie, ...
5
votes
1answer
536 views

Security and authentication problem

We have a sample scenario and we would like to receive some feedback and some solutions regarding possible security schemes. First of all, lets imagine a real world scenario: Imagine that a user ...
7
votes
3answers
309 views

Defense in depth vs low complexity - Balancing point?

I've asked a few questions relating to schemes for various security-related functions, and posited schemes to accomplish those goals. In the responses, I see a conflict between two fundamental ...
244
votes
11answers
58k views

Why shouldn't we roll our own?

Why shouldn't we create our own security schemes? I see a lot of questions around here about custom crypto and custom security mechanisms, especially around password hashing. With that in mind, I'm ...