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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12
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3answers
11k views

help understanding client certificate verification

I am creating an API that only certain computers should have access to. Communication will be via SSL between the server and the clients. In order to verify that a client has access, I would like to ...
12
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2answers
679 views

How do I prevent my twin sister's “pulled from public record” information from being used when I try to answer security questions?

Several times in the past months, I have been asked security questions that are "pulled from public record" to verify my identity, either over the phone or on a website (Chase Bank, Walgreens ...
1
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2answers
263 views

Authentication without saving password

Are there any security problems with following authentication protocol? when user creates hers account, she provides her username and password. I store the username and blowfishEncrypt(toEncrypt = ...
6
votes
4answers
616 views

Banking application login leaks information

My question is regarding the online banking application of a large credit card organisation. The login process for this application works as follows: User visits the homepage of the bank. User ...
1
vote
2answers
878 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 ...
1
vote
1answer
864 views

Public web server and AD- based Kerberos authentication

I would want to use SPNEGO/Kerberos protocol on a public internet webserver for specific remote ip addresses coming from corporate intranet. Other authentications methods are used for other addresses ...
6
votes
5answers
1k views

Is behavioural analysis (e.g. keystroke dynamics) a reliable security mechanism for MFA?

The typical set of multi-factor categories is as follows: Something you know (e.g. a password) Something you have (e.g. a hardware token, or key file) Something you are (e.g. a fingerprint or retina ...
7
votes
2answers
1k views

Does having a passphrase and SSH key qualify as two factor authentication for PCI?

I am working on getting our company's servers PCI SAQ-C compliant (credit card data passes through our system but is not stored by our system). We have SSH access to administer the servers and all ...
0
votes
1answer
6k views

3 or 4 characters long username from security point of view

I have on my site the ability for the user to choose his/her username that is 4-20 characters long. But some users could have names like "Amy" "Eva", "Ian" etc. Should I stick with 4 letters or go ...
13
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3answers
16k 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 ...
0
votes
1answer
168 views

How do I prevent my Rails application from attack? [closed]

My website is being nuked by new signups and new posts some of which don't even have user.id associated with. How do I solve this? What code should I add to the user#new page and/or post#new page. ...
8
votes
3answers
3k 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 ...
1
vote
1answer
662 views

RADIUS proxy chains

RADIUS is a widely deployed remote authentication protocol. I'm looking here at its use in wireless roaming. The RADIUS protocol allows for proxies and chains of proxies: |CLIENT|<->|Access ...
5
votes
3answers
913 views

Two-Factor Authentication: When is it worth it?

I was reading this article, and it triggered the question: Why not use two factor authentication? In his case, it both possibilities were enabled anyway, so this looks to me like it's two attack ...
3
votes
1answer
5k views

what is the role of RADiUS server and Active Directory to increase the security in wireless networks?

In the CBT Nuggets Video Training, one slide about Wireless networks : i want to know about the role of Radius to increase the security and how? in this project: Deploy Active Directory and ...
5
votes
4answers
2k views

Client Certificate in SSL HandShake insecure?

Imagine we have an application which is trying to establish a secure connection to a server by using SSL. Now we want the user to authenticate himself with a client certificate which he stores in an ...
6
votes
1answer
3k views

What is the opaque field in HTTP Digest Access Authentication used for?

Is the opaque field really used for anything? It is specified in the RFC, but is not implemented in Apache. Also, the RFC does not state a reason for having opaque, it is only mentioned as a value ...
0
votes
2answers
552 views

Pre boot authentication for Android phones [closed]

is there any way to have pre boot authentication on android phones? It would be nice if it would work with YubikeyONE's one time password mode.
2
votes
3answers
4k views

Dealing with untrusted administrators in a Windows domain

I'm providing consultation to a company, where they have domain-joined Windows workstations. One basic requirement is that they don't want anyone (including the an administrator) to be able to login ...
18
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6answers
3k views

Why do we ask for a user's existing password when changing their password?

In a web applications context, when a user wants to change their current password, generally they would have to enter their current password first. However at this point, the user has already been ...
5
votes
4answers
3k views

Throttling failed login attempts: exponential timeout? by IP? using a session cookie? captcha?

I'm beginning to think this is not as simple as it looks, and many "accepted" answers here and in SO have alternative answers that criticize them. Here is what I have gathered so far Most of what I ...
0
votes
1answer
454 views

Protect database resources from fake data inputs via web forms

Scenario: I'm working on a project that needs to accept large amounts of data (customer data) from its users. So it can be normal to have a user trying to add 10,000 or 100,000 records at a time. In ...
2
votes
1answer
107 views

What's the best way to enumerate log/sign in attempts?

For sign in via a website, what is the best way to count the number of attempts that is: least vulnerable to tampering reliable quick The system would: use HTTPS throughout the sign on phase (at ...
0
votes
1answer
11k views

How to create trusted chain of certificates if I have the last certificate?

Good day. During last two weeks i had been trying to create my xmpp client app which will be connect to the xmpp server via TLS(because server it's using) My server is: telnet xmpp.odnoklassniki.ru ...
9
votes
2answers
6k views

Keeping user session alive - security considerations

We have recently developed some functionality for our web app to allow a user to remain logged in indefinitely, and are interested in knowing the security ramifications of doing so. The goal of this ...
6
votes
3answers
10k 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 ...
-2
votes
2answers
952 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 ...
22
votes
4answers
20k 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?
32
votes
11answers
4k views

Is it safe to use a weak password as long as I have two-factor authentication?

I'm careful to use strong passwords (according to How Big is Your Haystack, my passwords would take a massive cracking array 1.5 million centuries to crack), I don't reuse passwords across sites, and ...
3
votes
2answers
267 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
216 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
921 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 ...
3
votes
4answers
476 views

Login form authentication logic

I am building my login form action, and I want to make sure my logic is solid and as secure as possible. 1.) First I check if the provided e-mail address exists in database, if not, I show a generic ...
6
votes
3answers
197 views

Getting automatically logged in to others session via Wi-Fi

Recently, I experienced a very strange behaviour on our Wi-Fi network: we share a Wi-Fi network using a simple router. One of us pays the bills and he's the one, who got the management account from ...
56
votes
12answers
3k views

How do you log in from an unsecured computer?

Suppose that you are on a cybercafe, at a friend's home or at your work office, and you need to log in on a site, but you feel that the the computer can not be trusted (e.g. your friend isn't ...
7
votes
2answers
5k 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 ...
-2
votes
1answer
303 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 ...
5
votes
2answers
2k 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 ...
16
votes
2answers
558 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 ...
7
votes
2answers
755 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 ...
16
votes
2answers
28k 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 ...
5
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1answer
3k 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?
7
votes
4answers
368 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 ...
3
votes
1answer
1k 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
325 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
154 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 ...
2
votes
1answer
247 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
1k 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 ...
10
votes
2answers
1k 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 ...
1
vote
0answers
304 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 ...