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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6answers
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Appropriate password requirements for a login (OpenID) service/provider/delegate/thing

This is with regards* to Stack Exchange's upcoming OpenID provider (and in particular, discussion about password requirements). Currently, password requirements are: Must contain 3 of: lower case ...
7
votes
2answers
1k views

Any advantage to securing WiFi with a PSK, other than to keep out unauthorized

As I understand WiFi with a PSK, such as WPA(2)-PSK or WEP, anyone on the same network can decrypt anyone elses packets because everybody has the same key. In which case, if you are not going to ...
4
votes
4answers
612 views

Why self-signed https is less trustworthy than unencrypted http?

It wouldn't be far-fetched to guesstimate that at least 50% of the web traffic can be intercepted in 2014. However, a guesstimate of active interception attacks is likely an order of magnitude ...
205
votes
7answers
39k views

What's the rationale behind Ctrl-Alt-Del for login

Why is Ctrl+Alt+Del required at login on certain Windows systems (I have not seen it elsewhere, but contradict me if I'm wrong) before the password can be typed in? From a usability point of view, ...
53
votes
3answers
99k views

What is the difference between authorized_key and known_host file for SSH?

I am learning basics of SSH protocol. I am confused between the contents of the following 2 files: ~/.ssh/authorized_keys: Holds a list of authorized public keys for servers. When the client ...
50
votes
4answers
50k views

How do I secure my REST API?

In Detail here's the problem: I'm building an Android app, which consumes my REST API on the back-end. I need to build a Registration and Login API to begin with. After googling for a while, I feel ...
34
votes
4answers
19k views

Demystifying Web Authentication (Stateless Session Cookies)

I'm currently researching user authentication protocols for a website I'm developing. I would like to create an authentication cookie so users can stay logged in between pages. Here is my first ...
30
votes
4answers
4k views

Disclose to user if account exists?

Someone told me it shouldn't be possible for someone to detect if a certain email address is a registered user on a Website. So, for instance, when the user asks to reset his password, you should say ...
19
votes
4answers
9k views

avoid hitting DB to authenticate a user on EVERY request in stateless web app architecture?

Summary Once a user logs into a web site and his username/password credentials are verified and an active session is established, is it possible to avoid hitting the DB for each and every request ...
55
votes
7answers
9k views

Are passwordless SSH logins more secure?

I had a long discussion with my co-workers whether key-based SSH authentication (particularly for OpenSSH) is more secure than authentication using passwords. My co-workers always connect to servers ...
46
votes
9answers
4k 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 ...
26
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5answers
3k 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 ...
25
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9answers
2k views

Why do some people really hate security via client-side?

For instance, lets look at a common login system for a website HTTPS connection is made User submits credentials via POST Server-side code hashes the password and looks if it matches the user name ...
23
votes
6answers
2k views

How to secure a WiFi network?

What do I have to do to secure a WiFi network? Is there any best practices? I have been recommended to use WPA2 encryption on the router, is that enough? What can I do to improve the security even ...
22
votes
8answers
1k views

How to protect against brute forcing

How do you properly implement defenses against brute forcing? Is it best to store how many times someone tried to log in and block them after X attempts? And how would "someone" be identified? With ...
14
votes
3answers
7k views

Is the Facebook login form using SSL without https in the URL?

If I go to http://facebook.com, I am not redirected to https://www.facebook.com. If it doesn't have https in the URL, can the login be secure? Usually I am redirected to an https page on other sites? ...
14
votes
6answers
18k views

Securing an API for mobile access

I've built a nice REST/JSON API that is used by other companies (our clients) as a B2B service. Each of our clients has a username/password pair, and we also do HTTPS and validate the source IP of ...
13
votes
9answers
842 views

Anybody have additional information on the EMC RSA SecurID compromise?

The Security Advisory Press Release here doesn't have much information, the email that alerted me to this didn't help much more, and unfortunately I heard about the two Thursday evening conference ...
12
votes
3answers
4k views

Is it possible to use a GPG or SSH key for web based authentication in a secure fashion?

Let's say hypothetically I am writing a web application targeting technically inclined, security-conscious users who have no problems generating and using GPG or SSH keys. Is it possible to use said ...
7
votes
3answers
36k views

Four-way Handshake in WPA-Personal (WPA-PSK)

Can someone explain to me in what consists the Four-way Handshake in WPA-Personal (WPA with Pre-Shared Key), which informations are being sent between AP and client, how is it possible to find the AP ...
16
votes
7answers
10k views

Forgotten password or reset link, which is more secure to email?

I originally posted this as a reply here in this thread but didn't get much feedback on it, and now I'm curious as to what others think is the best approach, or if there is any difference between the ...
14
votes
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?
8
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6answers
1k views

Logging in a user after password reset via link

Lets say password reset functionality flow is the following: User submits email address used for his account. An email is sent to that email address with a link with a password reset hash. Upon ...
19
votes
5answers
108k views

Can someone steal money from my bank account if they know my IBAN and personal details?

To deposit money into your account, some websites require that you provide them with a lot of details about your bank account: name, complete address and IBAN which includes your account number and ...
7
votes
6answers
3k views

Is denying login after incorrect attempts ineffective?

Generally denying login attempts after X amounts of incorrect attempts for Y amount of tries is a very basic way to prevent bruteforce attempts or malicious login attempts. Yet, surely doing this is ...
15
votes
5answers
1k views

How should passwords be stored if they must be recoverable?

By "encrypting" passwords you are violating CWE-257: Storing Passwords in a Recoverable Format. But this is exactly what the French government wants. They want to be able to obtain the passwords of ...
10
votes
1answer
3k views

How will security need to be changed if P=NP?

If we suppose that it is found that P=NP, how will security measures need to be changed? I'd like to know the major security measures that are affected, and how they would need to be changed. We can ...
6
votes
7answers
4k views

How can I best manage root passwords for many servers?

Lets say I have two racks with about 40 nix servers in them. I don't want to set all of the root user passwords all the same do I? If not how do you manage and keep up with all of the passwords? Is ...
6
votes
3answers
578 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 ...
6
votes
3answers
1k views

Is there a way to accept signed requests without storing client's password in plaintext?

We are developing REST Web service. We will give Identifier and Secret string to each of our REST clients. When doing requests, clients will authenticate themselves using HMAC algorithm (they will ...
7
votes
5answers
2k views

Preventing online voter fraud

As part of a promotional campaign, my company wants to launch a site where users (and potential users) of our product will be required to register and vote for certain choices. Depending on how ...
7
votes
1answer
694 views

Inconsistencies found in OpenID Provider's HTTP Headers. Which one is the most secure that I should imitate in my STS, and Relying Party?

I'm comparing the HTTP headers of the various providers (LiveID, Google, Yahoo, etc) and notice a broad inconsistency in implementation on the sign in page, sign out page, and subsequent pages. ...
4
votes
7answers
652 views

Is it wrong to root login with SSH?

I've long been under the impression that with unix, you should never login as root. Now I've started using Virtual Private Servers over at DigitalOcean, and some advice is to use SSH keys to login as ...
8
votes
2answers
501 views

Is there a way to negotiate a secret between 2 parties with no prior knowledge?

Is there a way for 2 parties to negotiate a shared secret (for example, a session key) without having a pre-shared knowledge? SSL does this by using asymmetric encryption. Is there any other way to ...
7
votes
2answers
3k views

MAC vs Encryption

I understand the difference between MAC (eg. hmac_sha256, etc.) and Symmetrical Encryption (eg. rc4, etc.), but my question is what advantage does MAC solve that using encryption doesn't? I know that ...
3
votes
2answers
670 views

Should the Keygen element be used to create a certificate for mutual auth TLS? What alternatives are there?

I'm interested in using mutual auth TLS to improve the security of my javascript based webservices . I've looked at the Keygen element and given all its issues, not sure if this can even be used for ...
3
votes
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 ...
-2
votes
3answers
1k views

Two-factor authentication Without Mobile Phone

Two-factor authentication is based on the notion of “something you know” and “something you have”. Is it absolutely necessary for having your mobile phone involved in two-factor authentication, which ...
11
votes
9answers
2k views

Why do we authenticate by prompting a user to enter both username and password? Does prompting the password only suffice?

I don't know why do we authenticate by prompting the user to enter both username and password. In my mental model, prompting password only suffices. The reason is as follows: Assume there are x ...
8
votes
3answers
2k views

What are the security implications of using TOTP for single factor authentication?

(Note: I am not actually planning to do this. This question is strictly theoretical.) TOTP is commonly used as the second factor in Two Factor Authentication. It is an open standard with available ...
6
votes
2answers
1k views

Storing third-party auth info securely

Suppose there's a multi-user web application that requires access to user's mailbox (on third-party service, like gmail, etc.). This access needs to be persistent. Which means we'd have to store user ...
4
votes
6answers
2k views

How to “demonstrate” man-in-the-middle attack?

I'm TAing a particular course on system security. A specific example is transitting the password in plain text when developing a web application (as part of a class project). Over the years a bunch ...
4
votes
1answer
741 views

How many authentication factors are there?

The three classes that we all know and love: Something you know. Something you have. Something you are. I've also seen references to "somewhere you are". Is this really a fourth factor? How many ...
41
votes
7answers
10k views

Why isn't open WiFi encrypted?

As far as I understand, WiFi networks that require no password send traffic through the air unencrypted. Those that require a password encrypt each connection uniquely, even if they're all using the ...
32
votes
3answers
25k views

What are the dangers of allowing “less secure apps” to access my Google account?

According to https://support.google.com/accounts/answer/6010255: Google may block sign in attempts from some apps or devices that do not use modern security standards. Since these apps and devices ...
22
votes
5answers
5k views

How to uniquely identify users with the same external IP address?

I have created a login module on my website. I was able to deal with simple brute force attacks since I can identify the user based on username/email and throttle their login based on failed login ...
30
votes
6answers
4k views

How safe are employee laptops in China against International corporate espionage?

I recently took a business trip to China. Our IT department told me I could not take my normal machine, and instead gave me a loaner. This loaner had MS Outlook and was linked to my normal company ...
27
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9answers
13k views

Two-Step vs. Two-Factor Authentication - Is there a difference?

These days, there's pretty much three forms of authentication in general use on the web: Single-factor authentication, e.g.: PIN or password. Two-factor authentication, e.g.: Single-factor plus a ...
29
votes
3answers
14k views

Should we store accesstoken in our database for oauth2?

I have a requirement to implement Facebook and Google login in my web application. I also need to access a user's Facebook/Google+ friend list. I have gone through the complete OAuth2 documentation of ...
16
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3answers
5k views

Computationally simple, lightweight replacement for SSL/TLS

Target hardware is a rather low-powered MCU (ARM Cortex-M3 @72MHz, with just about 64KB SRAM and 256KB flash), so walking the thin line here. My board does have ethernet, and I will eventually get ...