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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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 ...
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3answers
2k 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 ...
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0answers
79 views

Pages restricted to certain IPs, safe? [duplicate]

Possible Duplicate: In what scenarios is relying on source IP address as a security control acceptable/unacceptable? If a website has a page which only renders for certain IPs, is there ...
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2answers
2k views

Is Access Control Through MAC ADDRESS a practical/secure solution

I run a small local gaming website with a custom admin panel I coded to let trusted members do administrative tasks through the software's API. Since their IP Address is dynamic, can I authenticate ...
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7answers
381 views

Aren't permanantly logged in accounts inherently insecure?

The basic premise behind a "keep me logged in until I log out" feature is a cookie is stored with some identifier that is used to log the user in again when returning to the site. While these ...
5
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1answer
264 views

Using AD authentication in a publicly accessible webapp

I am sys admin working with a development team who is extending a publically accessible .net web app that currently uses forms authentication with usernames/passwords (hashed) stored in a sql ...
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3answers
442 views

Locking down web-based admin areas with personal SSL certificates

I've been tasked to setup a secure platform, where I've been asked to assign personal SSL certificates to administrators, and have the server only allow persons into the administration areas that have ...
5
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6answers
902 views

How do I secure my login page?

The login page is the starting point to any web site and the most important thing to authenticate the user. When I begin to build any web application, I take a lot of time to think about how to ...
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5answers
1k views

Does two factor authentication prevent social engineering attacks

After reading this article from symantec I got to think how much all these social engineering techniques rely on the authentication system of users, a password. Considering three different additional ...
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2answers
3k views

What are the most common password salting methods?

I learned that the Sun guys used the login name as salt for password hashing. Is this a common approach? What are the most common salt values?
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3answers
6k views

What are the main advantages and disadvantages of webid compared to browserid?

What are the main advantages and disadvantages of webid compared to browserid? This question is inspired by this answer which got a number of upvotes despite being very vague on the topic of that ...
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5answers
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What are the downsides of BrowserID/Persona compared to OpenID/OAuth/Facebook?

Mozilla went live with a new service called BrowserID/Persona (announcement, background). It is intended to replace current single-sign-on solutions such as OpenID, OAuth and Facebook. One advantage ...
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9answers
1k views

What's a good way to trigger a hidden 'distress signal' in instant messaging?

Here's the scenario: Alice and bob use Off-the-record messaging to communicate over IM. The have: Encryption Authentication Deniability Perfect forward secrecy They communicate after ...
6
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2answers
588 views

Cellular phone cloning

It is known that certain methods of authentication are used to tie a particular device to a particular phone number, so that cloning can be prevented. What are these authentication mechanisms? ...
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2answers
923 views

OAuth User revoke token

I haven't read it myself but a colleague told me that the end-user can revoke his/her OAuth token. I searched but I couldn't find enough docs on: is this true / is the end-user the one to revoke the ...
6
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3answers
1k 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. ...
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4answers
1k views

Can .htaccess and .htpasswd really protect me?

I want to set up a kind of personal wiki where I can store various sensitive information. However to make it 100% portable and and just plain convineant, I want to put it on the Internet. I'm sure at ...
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2answers
2k views

How does openid implement Single sign on?

I'm wondering which security model is behind the OpenID. Is it anything like kerberos?
265
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7answers
211k views

RSA vs. DSA for SSH authentication keys

When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type). What is the difference between RSA and DSA ...
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2answers
232 views

TCrypto - Comments about design decisions I made?

I have pushed some code to GitHub to demonstrate the usage of symmetric key encryption in PHP. It is a small key-value storage library and it (optionally) offers ability to encrypt the stored ...
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3answers
135 views

Question on information retrieved from systems that could potentially lead to exploits

Usually it is advised, when one wants to secure an application, to "provide" as little information, or better yet, no information at all to unauthorized (possibly malicious) users. I'm thinking of ...
14
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4answers
4k 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 ...
2
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1answer
898 views

iOS/Android authentication and security

Here is what I am trying to do and can anyone provide some best practice advice for authentication and security? Each user will have their own private database on the cloud. He will have his local ...
8
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4answers
2k views

How to protect ftp account information in the source code of a program

I wrote a game which stores high score information on an ftp server. In the the source code I need to write out the ftp link with the account name and password in it. For example: url = new ...
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4answers
1k views

Is it a bad idea for an information holder to e-mail a user their password?

A couple of websites with which I'm registered have, after a period of inactivity on my part, each sent me an e-mail to remind me that I'm still registered. In each case, that e-mail has included my ...
8
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3answers
804 views

zero knowledge proof and its protocol

In Zero-Knowledge Proof where we take the analogy of Peggy (Prover) and Victor (Verifier): In this story, Peggy has uncovered the secret word used to open a magic door in a cave. The cave is ...
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1answer
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Deploying a campus WiFi network that authenticates against an AD LDAP

We are looking to deploy about 15-20 Cisco 1131ag access points on campus. I have been reading up on different authentication methods, but I don’t know what will be the best long term solution that ...
8
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2answers
695 views

Is a rand from glibc's rand secure for a login key?

Same question as Is a rand from /dev/urandom secure for a login key, but with glibc's rand function instead of /dev/urandom. And what would be a sufficiently secure seed generator?
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1answer
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How can I avoid sending passwords in plain text when logging into a website?

Suppose that I login to a website. When I type my personal data, aka, password and email, the password is sent in clear text to the server, correct? Then, a network card in promiscuous mode can ...
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6answers
7k views

How do some sites (e.g. online banks) only ask for specific characters from a password without storing it as plaintext?

I thought How can a system enforce a minimum number of changed characters... would answer my question, but it seems this is a different case. When I sign on to my online banking account, I'm prompted ...
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7answers
2k views

Sharing passwords and credentials between founders and employees

What's the best way to share passwords and credentials from the business's various accounts in a secure manner? For example, email doesn't work because if someone gets into one of your employee's ...
7
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1answer
310 views

Collision attacks on OCB?

I've been looking into the OCB cipher mode and everything I hear sounds good. I was planning on implementing it. Everything except for this lone voice, that is: Collision attacks on OCB: We ...
25
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5answers
2k views

Should usernames be kept secret?

Help me settle an discussion among colleagues and guide future design: Even in a high impact scenario: e.g. protecting payment application or government gateway but in an Internet accessible ...
362
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21answers
69k views

How does changing your password every 90 days increase security?

Where I work I'm forced to change my password every 90 days. This security measure has been in place in many organizations for as long as I can remember. Is there a specific security vulnerability ...
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3answers
269 views

Choosing an authenticated encryption cipher mode without associated data

In the application I'm writing there is need for a huge amount of private data transfer on the order of eighty gigabytes, but there is no public data. I'm looking especially to gain ...
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1answer
2k views

What is the purpose of AEAD?

I think I need to correct some misunderstandings I have about AEAD. What is associated data used for in authenticated encryption?
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6answers
1k views

Is This Login Security Enough?

I'm coming up with my next login system for admins of an ecommerce website to have login form is SSL secured password is converted to sha256 before being transmitted (bcrypt is too slow still for ...
8
votes
3answers
727 views

Which authentication at the end of the Secure Remote Password protocol?

For the the client and server to prove to each other that they have the same premaster shared key, the original author suggests this: M = H(A | B | K) --> <-- H(A | M | K) ...
7
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2answers
559 views

How does external authentication work?

For example, I can log in to stackexchange websites by logging in to external websites such as OpenID, Yahoo, etc. How does this work? How do the websites (SE and Yahoo!, for example) communicate? How ...
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2answers
4k views

Secure communication between applications using SSL Certificates

I am looking for a way how to secure communication between our applications. There is a "server" application listening on some TCP port and "client" application which is communicating with the ...
9
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1answer
416 views

Optimal variable sizes in the Secure Remote Password protocol

I am implementing the Secure Remote Password protocol: U = <username> --> <-- s = <salt from passwd file> a = random() A = g^a ...
6
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2answers
735 views

Implementing Secure Remote Password: Constructing the verifier

The SRP protocol as described in RFC 2945 generates the password verifier: x = SHA(<salt> | SHA(<username> | ":" | <raw password>))` v = g^x % N I have three questions: why use ...
14
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2answers
3k views

Encryption strategies for multi users access in production systems

I am pretty unknown to encryption strategies in production environments. So my concern is to find a solution how to strongly encrypt data, but make it available to multiple users with different keys. ...
18
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2answers
5k views

Why is it always `HASH( salt + password )` that we recommend?

Browsing over this site, many forums, online articles, there's always one specific way we're suggesting to store a password hash: function (salt, pass) { return ( StrongHash(salt + pass) ) } But ...
6
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3answers
1k views

Using Secure Remote Password without sending the username in the clear

To initiate a key exchange using the SRP protocol the client sends the username so the server can look up the salt and password verifier. Is there a simple way to change this so that an evesdropper ...
5
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1answer
317 views

Using Secure Remote Password without embedding the modulus

The SRP protocol as described by the author assumes that the large safe prime modulus and generator are embedded into the client and server rather than being transmitted as part of the protocol. ...
7
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1answer
4k views

Obtain credentials by spoofing WPA/WPA2 Enterprise network?

I have a large scale wireless network secured using WPA/WPA2 Enterprise authentication. Recently, I was made aware of the possibility that someone may use a dd-wrt router and a computer to spoof the ...
14
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2answers
4k views

Hiding user account names from unauthenticated RDP sessions

This is for a Windows 7 Ultimate system, which is not a member of a domain. When I log into the system locally, I am required to either manually enter my user ID or authenticate with biometrics. The ...
0
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1answer
119 views

WLAN Router authentification [duplicate]

Possible Duplicate: How can I ensure that I connect to the right wireless Access Point? Is it true, that WLAN routers aren't authenticated by clients? The only "authentication" is SSID and ...
4
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4answers
766 views

Ensuring a web-service only processes requests from specific computers

I'm in the process of designing a system that consists a client application and a single web-service. The client is distributed on several machines (installed by me or a colleague), and the ...