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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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 ...
11
votes
7answers
2k views

Prevent denial of service attacks against slow hashing functions?

I've been thinking about bcrypt recently, and what I wonder is if there's a way to deal with the inherent (D)DoS problems with slow hashing functions. Namely, if I set up bcrypt so my machine takes ...
80
votes
11answers
12k views

“Username and/or Password Invalid” - Why do websites show this kind of message instead of informing the user which one was wrong?

Lets say a user is logging into a typical site, entering their username and password, and they mistype one of their inputs. I have noticed that most, if not all, sites show the same message (something ...
20
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
6k 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? ...
13
votes
9answers
782 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
7answers
8k 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?
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 ...
12
votes
6answers
14k 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 ...
8
votes
1answer
2k 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
3answers
435 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 ...
7
votes
1answer
602 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. ...
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 ...
4
votes
6answers
3k 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 ...
8
votes
2answers
450 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
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 ...
3
votes
2answers
488 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
1k 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 ...
-3
votes
3answers
986 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 ...
4
votes
1answer
603 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 ...
51
votes
7answers
8k 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 ...
43
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 ...
15
votes
3answers
4k 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 ...
27
votes
7answers
3k views

What is a good way to authenticate a user to a smart phone?

What would be a good way to authenticate a user to a smart phone? By good, I mean that it is both secure, and user-friendly. Passwords don't seem to be the best fit because a password needs to be ...
24
votes
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 ...
23
votes
7answers
6k views

How to prevent cheating (extra votes) in online contests?

Mitigating Cheating & Voter Fraud in Online Contests… We run online contests of various sorts that involve users voting on entries (usually one vote per user per day). The prizes range from ...
22
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
4answers
609 views

How does using OpenID affect webapp security?

Using OpenID for authenticating users grows in popularity and, in fact, makes a webapp easier to use. But what are the security considerations one should bear in mind when deciding whether to ...
18
votes
8answers
7k 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 ...
12
votes
2answers
19k 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 ...
8
votes
4answers
10k views

Difference between authentication and identification [Crypto and Security perspective]

I am always confused by the way the word authentication is used in security literature (i.e., outside the crypto realm). Most of the time I understand that they are actually implying identification. ...
21
votes
12answers
3k 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 ...
22
votes
4answers
7k views

How secure is Windows 8's Picture Password login?

The final Windows 8 build has been released to manufacturing. One of the new features of Windows 8 is "Picture Password", where the end user logs on to Windows by clicking a specific pattern on the ...
19
votes
9answers
4k views

Can IP address be a component of 2-factor authentication?

I have a bunch of Linux machines that I wish to administer over the Internet. I currently use SSH keys, but have been advised to use 2-factor authentication. SSH Keys are something you know. Is an IP ...
17
votes
6answers
5k 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 ...
37
votes
6answers
5k views

Is a website published in an obscure directory comparably secure to being placed behind a login? [duplicate]

Let's say I create a microsite for a client that contains confidential business information. We need to place this in a location the client can access, in order for them to approve for launch. If we ...
22
votes
1answer
5k views

Is there a standard for printing a public key as a barcode?

Is there a standard for storing a public key printed on paper? Say, I want to hand out business cards with my public key pre-printed on them at a key signing party to help build the web of trust. My ...
17
votes
5answers
88k 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 ...
14
votes
2answers
959 views

Password and Generated number - How does it work?

In my company, they don't allow accessing the company email or servers from outside the company network. To access the email from outside the network, you have to use: Username, password and a number ...
8
votes
3answers
1k views

Verify Login and Encrypt with PBKDF2

I'm writing a desktop application where I'm using PBKDF2 to generate an encryption key to AES-128 encrypt the config file. The config file contains a crypo-random key that's been used to encrypt the ...
7
votes
6answers
598 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 ...
44
votes
1answer
3k views

What's the risk if I accidently type my password into a username field (Windows logon)?

I'm used to logging into my personal Mac which is a password-only field (like waking from sleep mode). Sometimes I have to use a Windows network on which I have an account, but of course I have to ...
27
votes
3answers
964 views

What is this authentication method/approach called?

Background: I want to implement something like this in our websites, and I'm looking for advice and possibly APIs that allow this out of the box rather than re-inventing the wheel, but I can't even ...
11
votes
4answers
17k views

What is the difference between authenticity and non-repudiation

I'm new to infosec and doing some reading. Not surprisingly one starting point was wikipedia. In this article, authenticity and non-repudiation are listed as 2 separate 'Basic concepts'. My ...
10
votes
3answers
4k views

How does an SSL server prove its identity?

This document says that a challenge response authentication proves the servers identity. But is a man in the middle attack still possible if the client does not verify domain name ? Please help me ...
4
votes
1answer
968 views

Blackberry + RIM Bluetooth-based Smart Card Reader

Has anyone used this Bluetooth based smartcard reader? (scroll to bottom) If so, what are your experiences with it? Can you tell me if it's possible to require only the presence of the card + card ...
13
votes
5answers
1k views

Is there any reason to show the same message for invalid username as password?

I've seen a security question/requirement that a website login return the same error message for invalid password as for non-existent user. The idea being that this it makes it impossible to discover ...