Authentication - establishing the authenticity of a person or other entity. Not to be confused with authorization - defining access rights to resources.

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18
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12answers
2k views

Why do we even use passwords / passphrases next to biometrics?

In the last couple of days there were a lot of talking about passwords and passphrases, not only here, but on several blogs and forums I follow (especially after XKCD #936 saw the light of this ...
-1
votes
2answers
558 views

How can Facebook 2FA mechanism be hacked? [closed]

two-factor authentication process that uses one-time random code,I think season hijack can be used, I would like to know if there are more techniques to crack it. With season hijack, I think that if ...
4
votes
3answers
2k views

How to distribute client certificates without exposing private key?

I'm desgining a B2B web service based on WCF. As the number of clients is relatively small and security is a priority, i have chosen to go with X509 client certificates for client authentication. I'm ...
7
votes
4answers
3k views

why a client authentication is not commonly performed in the TLS protocol?

Is there any reason for this other than key/certificate management on the client-side?
3
votes
2answers
182 views

Secure login across two web apps

I have an requirement to implement cross-domain login for two web apps (APP1 and APP2) so that a user can access APP2 once they have logged into APP1. APP2 needs to know an ID of the user who is ...
3
votes
1answer
108 views

SRP: Can the client authenticate using only the stored hash?

Based on the description of SRP, it seems that it would be possible for a client application to cache the hashed password x and reuse it for subsequent authentifications. The actual password p doesn't ...
3
votes
2answers
448 views

User authentication + database encryption with same password

I'm working on a private project where I need to store a users financial data in a database. I'll encrypt this data using AES, and I'll be using scrypt to generate a AES ecnryption key from a more ...
14
votes
2answers
388 views

Which factors should I consider for devices that accept handwritten digital signatures?

These days many locations ask you to give your signature on a digital signature pad/device. As I am situated in Europe, the EU directive 1999/93/EC seems to regulate it. From what I have found out ...
4
votes
2answers
2k views

When using symmetric key encryption, do we need to sign?

Say we're using a shared key between two parties, that has been distributed using public key encryption, is it still necessary to sign any data that's encrypted using the shared key? Or is it enough ...
5
votes
3answers
323 views

DHE exchange and client authentication

If a server has a known public key and a Diffie-Helman exchange is performed and signed by that key, is there any benefit to authenticating the client before establishing a secure channel instead of ...
-2
votes
1answer
160 views

Digest authentication - client side [duplicate]

Possible Duplicate: Client side password hashing How one design support for digest authentication in client side. HTML form probably won't help. Does one need javascript and set the header ...
7
votes
2answers
349 views

An adequate message authentication code for REST

My REST service currently uses SCRAM authentication to issue tokens for callers and users. Tokens issued by the SCRAM exchange have an expiry time after which a repeated sign-in is required. We also ...
5
votes
2answers
476 views

How to login and encrypt data with the same password/key

I've made a "vault" web app in PHP for storing passwords, credit card numbers, etc. It's mostly just for myself, but I'm practicing building it with multiple users in mind. I use two way encryption to ...
5
votes
1answer
1k views

False negative in biometrics

In biometric systems preventing false positive is usually far more important than preventing false negatives. In what situations can false negatives be more serious than false positives?
17
votes
4answers
4k 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 ...
8
votes
2answers
8k views

How does ssh public key authentication work?

My basic understanding is this: The (connected to) server's sshd uses the public key to encrypt some message The client's ssh or ssh-agent decrypts it and sends something back (the message's ...
6
votes
3answers
240 views

How to suspend a user from my website and prevent them from creating a second account?

I am an outsourcing person, not a programmer. My website is a shopping website (think eBay). My website will need a user suspension feature, in case a user violates the terms and conditions. The ...
2
votes
1answer
331 views

Can Diffie-Hellman Anonymous be used as a cipher for SSL for one-way certifiate-based authentication

I want to use Diffie-Hellman anonymous cipher for SSL. I also want to use a one-way certificate for server authentication. Is this possible?
3
votes
1answer
211 views

Payment security on Android App

I am developing an application from which users browse and buy books. The client can be Android ,iOS, Mac. The server is ASP.net Web APIs. I know there are many payment services available. One of ...
3
votes
4answers
142 views

Strong authentication over insecure links

Let's begin by assuming that we're operating in either a corporate or Governmental environment where SSL man-in-the-middle interceptions are a given and that *all* traffic on the network between the ...
3
votes
1answer
153 views

Mitigate risk of security questions [duplicate]

Possible Duplicate: Do security questions subvert passwords? Many Web sites nowadays require a (hopefully strong) password along with some pretty easy security questions. Sometimes it is ...
2
votes
1answer
428 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 ...
8
votes
2answers
552 views

My bank makes me enter my password using the mouse. What's up with that?

Internet banking login process for Westpac requires user to enter the password using the mouse. It's annoying, what's up with that? Is it just to try and stop keyloggers on public computers or is ...
4
votes
2answers
855 views

Do Client Nonces enhance the security of HTTP Digest Auth?

As far as I understand the answer at http://security.stackexchange.com/a/3024/13447, client nonces are meant to prevent attackers from amortizing the costs of brute-force hash computations by being ...
1
vote
0answers
169 views

Verifying Authenticode signed executables and DLLs using OpenSSL API [closed]

I have installed openssl and now the rsa_test.c is running fine. What I want to do is: Open any exe or dll digital certificate. Extract the Thumbprint and PublicKey. The public key contains the ...
4
votes
1answer
179 views

Does DPAPI works if a user hasn't a login password?

I was wondering if the DPAPI will still work properly if a user doesn't have a a login password (like most of the home users). I can't find this information on Google or in the official documentation ...
1
vote
1answer
190 views

Device authentication mechanism

I am doing a project that needs device authentication with a gateway. What are some of the best ways of doing that ? Whether a certificate based mechanism is feasible in this case ?
3
votes
2answers
349 views

Wi-fi security using WPA or WEP

In current years we have used WPA and WPA 2 for the encryption of data sent over an 802.11 network. But in the past WEP is used . From time to time, many people say that WEP (Wired Equivalent Privacy) ...
8
votes
2answers
672 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? ...
1
vote
1answer
412 views

Silent (no user interaction) utility to clear cached credentials on Windows [closed]

Is there any way to clear cached credentials on Windows, that doesn't require: user interaction (e.g. a confirmation window); administrator access; or making a persistent change to the ...
4
votes
1answer
397 views

How to disable caching of form data?

A web page accepts user name and password data within an HTTP POST request. This POST request actually shows up as an entry in the browsers history. After user logout from the application and ...
-1
votes
2answers
86 views

What happens when and attacker changes the installed public keys in browser

I was reading about SSL. I understood that each browser comes with a predefined set of known public keys,which is then used to authenticate the messages. I was wondering what will happen when a virus ...
5
votes
1answer
368 views

Secure web user authentication even after server-side database compromise

By now, we should all know to use bcrypt or scrypt to store salted password hashes with a sufficient number of rounds. (See, e.g., https://www.owasp.org/index.php/Password_Storage_Cheat_Sheet) The ...
4
votes
2answers
2k views

How is user authentication sent in a public wifi? Radius/802.1x/EAP etc

I visit the airport, I pull out my laptop and connect to a network (no password needed). I open up my browser and i am presented with a screen saying I need to pay to use the network. If I pay, I ...
9
votes
2answers
505 views

Security of unencrypted wireless networks with authentication page

Some wireless networks, such as those offered by hotels and hotspots, are not encrypted (they don't require a pass phrase to connect) but have an authentication web page. For example, you connect to ...
8
votes
2answers
3k views

How does deauthing work in aireplay-ng?

I have a question of how aireplay-ng works when it deauths. I mean, it is really easy to disconnect another client from an AP: you just need to run the deauth command (in aireplay-ng) once, specifying ...
5
votes
4answers
1k views

MDK3 warns about WPA2 downgrade - how do I find the key in Wireshark?

While stress testing my router using MDK3, I got the message "REALLY BIG WARNING!!! Seems like a client connected to your target AP leaks PLAINTEXT data while authenticating!!" I viewed the tool ...
0
votes
2answers
257 views

Can you pick up any device specific information by monitoring bluetooth signals? [closed]

Could I use some sort of permanent device ID broadcasted by the bluetooth radio in my phone to do something like unlock my door? I don't want to have to ever pair the device, or take it out of my ...
10
votes
4answers
696 views

What is the key when facial recognition is used as a password?

I get the basics of what face recognition is and the fact that it is used to protect PC's and as a login replacement. However, if it was to be used for encryption, where the role of the key is played ...
2
votes
3answers
1k views

is it possible to create a login “key” out of a USB drive?

I was recently thinking about keeping my computer secure from physical access, and i decided that the safest way to keep my data under lock and key, was to do just that: Create a lock and key out of a ...
2
votes
6answers
768 views

Does Username + Password + Pin improve login security?

I've been asked to add a feature to a website to require a pin for users. The site currently uses username and password. If a user wants to change their password they need to supply the current ...
1
vote
1answer
512 views

Implementing SRP Challenge login system *with SSL* (Using PHP)

My question: Anyone knows how to implement SRP / Diffie-Hellman authentication in PHP (or if this has already been done)? (Some details) I'm using CodeIgniter with TankAuth (both latest version) ...
17
votes
6answers
2k views

How to verify that someone is who they say they are online?

I am working on an online job application web app and the question has come up about how we will verify that someone submitting an application is who they say they are. For example, we don't want ...
15
votes
4answers
373 views

Why aren't digital signatures the standard way to authenticate web clients?

The web is a mess of incompatible cookie schemes, asinine requirements ("your password must contain letters, numbers, and at least one symbol from !()-_., and must begin with a letter, and once you ...
1
vote
3answers
934 views

Testing http authentication via netcat

I'm currently trying to track down what I think is a false positive from Nessus, my attempts to netcat into the device are failing, but I believe the service is shut off anyway and Nessus is being ...
12
votes
3answers
3k views

Three-Factor Authentication for Windows

This HowToGeek article... http://www.howtogeek.com/67556/how-to-unlock-your-pc-by-being-nearby-with-a-bluetooth-phone/ ...got me thinking. Is there any software (or combination of software) that ...
5
votes
2answers
156 views

Windows Vista user logon integrity

Is it possible to delete some or all user session logon datetime records from Windows Vista? Is there any mechanism to give me confidence that individual records aren't deleted even if there isn't a ...
35
votes
9answers
3k views

Isn't OAuth, OpenID, Facebook Connect, and others crazy from a security standpoint?

I work with APIs all the time and I work with web developers who insist that OAuth, OpenID, etc are far superior than a home-brew method. Every site seems to be using these as well now for ease of use ...
10
votes
1answer
637 views

When authenticating ciphertexts, what should be HMACed?

Some have argued for using AES-256-CTR with HMAC-SHA-256 for authenticated encryption over AEAD-specific modes like EAX and GCM. However, when doing, this, what should be HMAC'd? And how? ...
2
votes
1answer
142 views

What authentication threat data exists?

I recently read an article that said there was not much data on which authentication threat vectors were actually being exploited in the real world. Eg what percent of password theft was by ...