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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37
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9answers
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Use additional “password” in Referer to hide private site?

I have a private (= I'm the only user) site at example.com/private/. Nothing else is published at this host (it's my domain). I don't want anyone to know that there is anything at example.com, ...
37
votes
4answers
5k 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 used by a registered user on a website. So, for instance, when the user asks to reset his password, you ...
37
votes
3answers
34k 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 ...
36
votes
8answers
5k views

Is the UK Parliament e-petition system trustworthy?

Over the last few days, I've been hearing often about the petition to (pratically) "repeat" the Brexit referendum and I noticed that it is an online petition. I noticed that the "sign petition" form ...
36
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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 ...
34
votes
3answers
3k views

Overarching term for 'authentication' and 'authorization'?

The internet is rife with 'authentication vs. authorization'-type questions. I'm not asking that here. I'm wondering if there is some overarching term that encompasses both of these. I've seen ...
34
votes
4answers
21k 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 bash:...
34
votes
3answers
23k 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 ...
33
votes
2answers
14k views

HMAC - Why not HMAC for password storage?

Nota bene: I'm aware that the good answer to secure password storage is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. Let's say ...
33
votes
2answers
4k views

Why does Google cripple the 2FA Google Authenticator PAM module?

If you enable 2FA for Google Apps the shared secret is 160 bits. The google_authenticator PAM module on the other hand seems to use 80 bits for the shared secret. According to RFC 4226: R6 - The ...
33
votes
4answers
2k views

What attacks, if any, are possible against Security Support Provider Interface (SSPI)?

I've been looking at SSPI recently, as it is used for authentication in a variety of Microsoft products. From the looks of it, it's based on GSSAPI and provides an abstraction for wrapping various ...
32
votes
7answers
5k views

How to prevent username and password matches when changing a username?

Let's say that I have a system where one of the security requirements is preventing users from choosing a password that matches their username. Usernames are not case sensitive but the passwords are. ...
32
votes
4answers
3k views

What is the point in having arbitrary username requirements?

I've looked around on Security.SE, but couldn't find much related to the following problem: I recently signed up for Chase Quick Pay as my method of being paid by a part-time job. I've heard of ...
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 ...
31
votes
3answers
5k views

Is there any advantage to splitting a password?

I've been reading about the LANMAN (LM) hash and I'm curious about a particular part of the algorithm. The LM hash is computed as follows: The user’s ASCII password is converted to uppercase. ...
31
votes
4answers
13k views

Are there technical disadvantages in using free ssl certificates?

Note this question is related, except this one is about free SSL certs. There are providers who are offering totally free entry-level SSL certs (like StartSSL). I was wondering if they are ...
31
votes
5answers
6k views

Could mint.com be more secure, and if so, how?

After reading a bit about mint.com on the money stack exchange, I wanted to give it a try. But frankly, it scares me a little bit. The site has a bunch of links explaining how they're so secure. I ...
31
votes
5answers
2k views

Why do some sites block pasting into username or password input fields?

I use a few websites that prevent me from copying & pasting into the username or password fields. It's quite frustrating when using a password manager, and if anything I'd think it discourages ...
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 e-...
30
votes
7answers
5k views

Silently Limiting Login Attempts

I've seen the following login rate limiting approach used on a web site I worked on, but I can't figure out if it's a good idea: After any failed login attempt, the site locks the user account for a ...
30
votes
5answers
2k views

What are the security implications of storing password blacklist?

I want to add a password blacklist that would prevent the 1000 most common passwords from being used in order to mitigate shallow dictionary attacks. Is there any negative implication of storing this ...
30
votes
9answers
17k 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 ...
30
votes
6answers
42k views

What is single sign on versus federated login?

What is the difference between Federated Login and Single Sign On authentication methods?
29
votes
4answers
25k views

How to achieve non-repudiation?

If I have a message that I need to send to another person, how do I achieve non repudiation ? Is digitally signing the message sufficient ?
29
votes
4answers
199k views

How do I clear cached credentials from my Windows Profile?

Windows seems to be saving my credentials for a variety of applications (terminal servers, etc) and I'd like to purge this data. How can I backup and purge this data?
29
votes
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 ...
28
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7answers
13k views

Could SQRL really be as secure as they say?

I just came across https://www.grc.com/sqrl/sqrl.htm With Secure QR Login, your phone snaps the QR code displayed on a website's login page . . . . and YOU are securely logged in. This ...
28
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 ...
28
votes
2answers
33k views

Why does HTTP Basic authentication encode the username and password with base64?

RFC 2617 requires that in HTTP Basic authentication, the username and password must be encoded with base64. To receive authorization, the client sends the userid and password, separated by a ...
27
votes
8answers
3k views

Share certain information only after death

After your death, you want to make sure that a special someone gets a vital piece of information (like the password to your bank account), but: You don't want anyone else to be able to get that ...
27
votes
3answers
1k 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 ...
27
votes
2answers
32k views

Session Authentication vs Token Authentication

I am trying to get a handle on some terms and mechanisms and find out how they relate to each other or how they overlap. Authenticating a theoretical web application and mobile application is the ...
26
votes
7answers
4k views

Does username length/complexity/uniqueness positively impact security?

Is having a longer/more complex username considered more secure than using a shorter/basic one? Would the uniqueness of a username positively impact security? This is assuming that adversaries aren'...
26
votes
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 ...
26
votes
9answers
3k views

How can I ensure that I connect to the right wireless Access Point?

Under Windows/Linux, client side. How can I ensure that I'm not connecting to a rogue AP?
26
votes
4answers
3k views

How is “something you have” typically defined for “two-factor” authentication?

A wide range of products claim to offer "two-factor authentication" (c.v. Two-factor authentication - Wikipedia). Most are deployed as "something you have" to be used in addition to a normal password ...
26
votes
2answers
7k 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 ...
25
votes
10answers
7k views

Two passwords for one account

Would it be a good idea if you had one account which would require two different passwords ? For example your login details were: email: example@gmail.com password 1: P4$$w0rd1 password 2: ...
25
votes
5answers
7k views

Why is “something you know” the weakest factor of authentication?

Quoting from CompTIA Security+ guide The first factor of authentication (something you know, such as password or PIN) is the weakest factor. Why? it makes sense when we say that humans/users ...
25
votes
10answers
6k 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 ...
25
votes
3answers
2k views

Is authentication using personal pictures more secure than passwords?

Statement 1 There is a start up called PixelPin. On the web site it reads: The PixelPin solution is simple and quick to use, yet very secure. PixelPin eliminates the traditional alphanumeric ...
25
votes
5answers
32k views

Preventing deauthentication attacks

I am helpless against some kiddy with backtrack who repeatedly uses aireplay-ng to deauthenticate legitimate users on my Wifi work network. I captured and analyzed the network traffic on my Wifi work ...
25
votes
2answers
13k views

How to set up OpenSSH to use x509 PKI for authentication?

I do not mean simply putting the public RSA key of a x.509 certificate into ~/.ssh/authorized_keys - I'm looking for a way to set up a ssh such that x.509 certificates signed by a pre-defined CA will ...
24
votes
4answers
4k views

Effectiveness of Security Images

Do security images such as those presented upon logging into banks provide any tangible security benefits, or are they mostly theater? Per my understanding, if somebody is phishing your users, it's ...
24
votes
4answers
22k 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?
24
votes
2answers
10k views

Role Based Authorization vs. Claim Based Authorization

What is the difference between "role based authorization" and "claim based authorization"? Under which circumstances would it be appropriate to implement each of these authorization models?
24
votes
5answers
3k views

Recommended policy on password complexity

Is there any research on how how a password complexity policy can increase or decrease the quality of passwords? If you don't have any requirements on the password then probably 90% of users will use ...
23
votes
9answers
5k views

Is it helpful to have a captcha on a login screen?

I introduced recaptcha to the login screen of a system. My goal was all about security things like dictionary/bots attacks or other thing of that type. The users now hate it, Some did not even ...
23
votes
5answers
6k 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 ...
23
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3answers
5k views

What are the disadvantages of implementing HTTP authentication in a web application? [duplicate]

I know that there are different types of authentication mechanisms available. One among them is the HTTP authentication. What is the danger in using this method compared to other methods?