Tagged Questions

3
votes
1answer
75 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, ...
2
votes
1answer
135 views

Improving Digest Authentication using PBKDF2

For a variety of reasons, I need to use digest authentication for a REST server that I have created. I have come up with an "improvement" that I believe strengthens the algorithm against MD5 attacks ...
3
votes
2answers
110 views

what is the difference between a mac and a digital signiture

I understand that a MAC algorithm takes a message and a private key as input and hashes them to a value. I understand that senders and receivers often use MACs to authenticate a message and check the ...
1
vote
2answers
112 views

How high is the entropy of this salt-generating code? (No code-reading actually necessary)

What is the best method? Assumption: I have a function that generates a number of medium-high entropy bytes Step1: I generate 3 of these medium-high entropy bytes. Step2: I hash these bytes using a ...
2
votes
1answer
162 views

Loki How to crack the password hash OSPF?

I have created for myself a lab of routers in GNS3 . Routing protocol between routers is OSPF. Now,by Loki penetration testing, I found that routers are the feature authentication. Using wireshark, I ...
2
votes
2answers
113 views

Easy protocol for email authentication

I'm cooking up a very simple system to send commands to a remote server via email. Everytime an email is sent to do_something@mydomain.net, the server runs a python script that does something ...
1
vote
2answers
120 views

Are SIP REGISTER transactions w/ HTTP Digest subject to replay attacks?

It is my understanding that the authentication during a SIP registration is done through some kind of an MD5 hashing algorithm known as HTTP Digest, and doing a tcpdump of the actual traffic I've ...
3
votes
3answers
594 views

Choosing a session ID algorithm for a client-server relationship

I am developing an application which has a client-server relationship, and I am having trouble deciding on the algorithm by which the session identifier is determined. My goal is to restrict ...
5
votes
3answers
381 views

Is my session-less authentication system secure?

So, I've created an authentication system. Poured over it for any kind of security flaws and tested the crap out of it. I think it's fairly secure, but there is one "different" by-design aspect of it ...
2
votes
1answer
156 views

Password authentication using DynamoDB

I'm working on a Mac app. I have users stored using DynamoDB. Authentication is needed to enforce access control on system-internal operations, such as uploading files to Amazon S3. Of course, I ...
7
votes
2answers
275 views

BCrypt's 72-character limit and using it as a general digest algorithm

Goal: have token/cookie-based authentication that doesn't require keeping sessions on the server TL;DR: What, if any, is the accepted mechanism to work around the 72-character limitation of BCrypt? ...
5
votes
3answers
243 views

How can Microsoft validate a shorter password on Microsoft accounts (MSDN)?

I recently ran across this when logging into MSDN. (I saw this screen after typing my initial credentials.) I have a 20+ digit password, however there's apparently a new requirement for Microsoft ...
-1
votes
2answers
109 views

Should I use salt to authenticate data?

I have a client and a server. The client makes a request containing userId, cardId, position (on the card) A hacker could just do the same http request with the next position. So I think about ...
1
vote
4answers
272 views

Are there vunerabilities with this authentication mechanism?

I am trying to come up with a way to implement token-based authentication for a REST API without the need for SSL. The goal here is to avoid sending any sensitive information across the wire. I was ...
1
vote
3answers
246 views

Using only password to authenticate user (no “username” field)

I am creating a client access system, to allow manage invoices, make payments, access information about their products and information/functionality alike. Supposedly there are less than 1000 ...
6
votes
2answers
398 views

HMAC Based Request Signing - Storing the Salt

I'm working on a (non high security) project that currently isn't live but might go live at some point. We have a REST API (implemented using Restlet and Neo4j) running on a server and an Android ...
2
votes
1answer
239 views

Cookie based session variables

I have a situation in which I cannot use a server-side session, but must allow users to log in, and for their logged in state to be persistent between queries. As with anything that involves crypto ...
3
votes
2answers
185 views

What algorithms can be used for device pairing?

I am to implement a system where android devices connect to a central server and have to register with different user accounts, so I have decided to create a pairing dance similar to what can be ...
0
votes
1answer
121 views

Securing communication

The problem: I have an open-source client (a Firefox add-on written in JavaScript) and a server containing somewhat sensible user information: username and user history (all from YouTube). The client ...
2
votes
2answers
188 views

Is it secure to have one salt or generate and send it over the air?

To authorize user I'm sending salted hash over the air. My question it is more secure to obtain randomly generated salt (but send unencrypted), or have one salt on client (desktop application) and ...
1
vote
4answers
219 views

sha512 as no-login-necessary token

My site has a news subscription system. When an item is updated, a notification email goes out to everyone subscribed to that item. You can un/subscribe via a form on each item's page. I wanted to ...
10
votes
4answers
2k views

https security - should password be hashed server-side or client-side?

I am building a web application which requires users to login. All communication goes through https. I am using bcrypt to hash passwords. I am facing a dilemma - I used to think it is safer to make a ...
3
votes
1answer
88 views

What are the implications of omitting the username in Secure Remote Password's verifier?

I consider implementing a Secure Remote Password (SRP-6a) verifier that omits the username from the x key hash. The intention is to allow authentication with multiple alternate user identifiers such ...
7
votes
8answers
569 views

Is the following authentication scheme secure?

I was trying to design an authentication system that would make it much harder to guess a password via brute force, and reduce the risk to a user if the hashed password was stolen through a snooping ...
19
votes
3answers
811 views

Am I wrong to believe that passwords should never be recoverable (one way hash)?

I recently forgot my password for our cable provider online account, only to discover that they sent it to us via plain text in an email. I quickly sent an email to customer support asking them if ...
6
votes
3answers
587 views

chosen plaintext attacks against MD5 and SHA1

According to http://tools.ietf.org/html/rfc2617#section-4.9, having the server chose a nonce but not having the client chose a nonce opens up Digest Access authentication to chosen plaintext attacks. ...
3
votes
0answers
132 views

Files for download and their hash numbers

I'm far from being an expert in the IT security and I have this maybe naive question. Many downloadable files are deployed on websites together with the corresponding hash numbers to ensure their ...
2
votes
3answers
193 views

Identify client based on computed hash

I'm currently developing a web application which will serve data to iPhone clients. In order to be the owner of the data, I don't want other clients to be able to get it. I thought I could use a ...
4
votes
2answers
1k views

Reference implementation of C# password hashing and verification

Does anyone have a reference implementation (ideally 3rd party certified, or government approved) way one-way hash a password for C# and or Java? Ideally,I'd like to see something that includes a ...
3
votes
2answers
468 views

BlackBerry client authenticating to Java Web Service

I already asked this question at StackOverflow here: http://stackoverflow.com/questions/4970681/blackberry-app-security and was directed to this site, can anyone pitch in as to how I can solve this ...