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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251
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7answers
199k 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 ...
3
votes
1answer
163 views

How can I successfully perform an xss attack on a dummy website? [closed]

in my security course, we were told to practice an xss attack using firefox on this website; http://permalink.co/ No worries, this is a website specifically setup for us to practice ...
3
votes
2answers
124 views

Is there any point in using two step authentication if you have strong passwords?

If you are in the habit of using strong passwords (randomly generated by password manager) is there any point in using two step authentication? Assuming that 99% of the time that when you enter a ...
3
votes
3answers
868 views

PCI DSS 2.0 and ssh keys

I know the real answer to the auditor. We are a smaller company under 40 total employees that is also PCI level 1 compliant. We've always used ssh keys on internal servers. You can't ssh in from the ...
3
votes
2answers
115 views

Why would you decouple your resource and login servers?

As described on this link, OAuth specifies that a login server and a resource server should be decoupled. The idea is that if one of your resource servers gets hacked, no password data is lost. All ...
2
votes
1answer
132 views

Smart lock protocol

I made an Arduino project to lock and unlock my door via my phone (with Bluetooth). It works well but it’s unsafe since I just send the lock and unlock command in cleartext, without authentication or ...
0
votes
1answer
53 views

MD5 before PBKDF2 on legacy software

I am mantaining a legacy software that uses MD5 in the following way: The client asks for a 16 byte salt when authenticating an account. The server generates a 16 byte salt, links it to the account ...
0
votes
1answer
91 views

Security tradeoffs while designing a mobile Web Service API

I'm not a security expert but I want to ask about tradeoffs in a web service API I'm designing for mobile apps. It is an API which tracks users' locations so yes, the data is reasonably sensitive. ...
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 ...
110
votes
8answers
46k views

Is BASIC-Auth secure if done over HTTPS?

I'm making a REST-API and it's straight forward to do BASIC auth login. Then let HTTPS secure the connection so the password is protected when the api is used. Can this be considered secure?
3
votes
2answers
166 views

Are AWS security groups sufficient to authenticate communication between instances? (HIPAA)

Say I have a private service that exposes sensitive information (PHI) via a REST API, and that I want to permit access to it from only one other service. Is it enough to partition these services ...
0
votes
0answers
21 views

Difference between Kerberos and GDOI?

What is the difference between Kerberos and GDOI, I know first is more toward authentication and latter is more toward multicast key management, can I use Kerberose protocol in GDOI for server and ...
1
vote
1answer
274 views

Risk of keeping OAuth2 client_secret in application

As an exercise, I'm developing a desktop application with which users need to log in to a web service. A logical use-case for OAuth2 one would say, but I'm beginning to doubt its usefulness. I am ...
0
votes
0answers
18 views

Difference between Kerberos and GDOI

What is the difference between Kerberos and GDOI, I know first is more toward authentication and latter is more toward multicast key management, can I use Kerberose protocol in GDOI for server and ...
1
vote
1answer
674 views

Untrusted connection visiting https://www.opensource.apple.com/

Somebody on Stackoverflow posted some code from https://www.opensource.apple.com/ When I click this link in Firefox (36.0) it says "This Connection is Untrusted". But other people on that thread on ...
1
vote
1answer
242 views

Is this a good approach to secure my REST API?

My application consists of a nodejs back end API but I am also developing a "reference" implementation of a JavaScript client, which is a backbone SPA. First of all; the API accepts only HTTPS ...
0
votes
1answer
114 views

SSO software – where is symmetric key stored?

In SSO software (Oracle E-SSO …), I heard about (primary) key encrypting user’s credentials, but I can’t read anything about how this key is managed ? When using smartcard, I can understand that ...
6
votes
3answers
3k views

OAuth2 - Resource Owner Password Credentials grant

The OAuth2 spec describes the Resource Owner Password Credentials grant type and authorisation flow here. I understand that only 'trusted' client applications would be allowed to use this grant, for ...
9
votes
2answers
1k views

How does Google detect new devices for two factor authentication

When you enable two step verification for google accounts, you get sent a code by SMS to enter in addition to your username and password the first time you log in with a new device. How do they ...
1
vote
1answer
75 views

Limiting Login Attempts [duplicate]

I have to set up a server that will allow remote logins. Obviously security is an issue. In this first pass we are discussing:- Locking a person for 15 minutes if they fail to login correctly three ...
0
votes
1answer
73 views

Why first kerberos message is not ciphered

When analysing Kerberos exchange (and other similars as Needham, Denning, etc.) I wonder why the first message where the identities of the client and remote are not encrypted. In case not encrypted I ...
3
votes
1answer
1k views

OAuth2 with client credentials v/s other auth mechanisms

For a REST API against which clients would be writing non-browser based, non-interactive applications, if OAuth2 is the authentication mechanism to be followed, then we would use the client ...
1
vote
1answer
93 views

OTP for syncing mobile device

Scenario: a web app with two-factor authentication using username/password and hardware OTP. Once logged into the app, one of the app modules should be used in a tablet or any mobile device without a ...
93
votes
17answers
23k views

Is “password knocking” a good idea?

With port knocking, you have to "knock" on specific ports in defined order to expose a port on which service is running. How about password knocking? For example you have three passwords: A, B and C. ...
71
votes
3answers
24k views

How does Google Authenticator work?

Google Authenticator is an alternative to SMS for 2Step verification, installing an app on Android where the codes will be sent. It works without any connectivity; it even works on plane mode. This ...
1
vote
1answer
51 views

Using a Cryptovariable with an API Designed for Human-Generated Passwords

I'm working with a vendor who provides an API with a user registration method clearly designed for human-generated passwords. We're calling the API in an offline server-to-server fashion, however, ...
1
vote
1answer
231 views

How to secure my REST API once user authenticates with Google on mobile client?

In my application, I build REST APIs so that user can interact with my application server. Since I do not want to maintain User/Passwords, my iOS app authenticates client using Google. This all ...
1
vote
1answer
62 views

Retrieve anonymous credentials

Background A registration process to acquire an anonymous, verified account goes like this: Registrant provides proof of individuality to a Registrar. Registrar verifies proof, ensures no prior ...
2
votes
0answers
378 views

JSON Web Tokens vs. SAML

I don't know too much about security. Specifically, I don't understand the difference between JSON Web Tokens, SAML and OAuth 2. If you could provide some pointers and high level overview of their ...
1
vote
1answer
373 views

Is it safe to store public key encrypted password in the Mobile Device for authentication purposes?

I have a Apache Cordova hybrid mobile app that needs to authenticate users, but we don't want to prompt for credentials every time the app is used. Some options came to my mind: Store the password ...
42
votes
4answers
6k views

Is it good practice to ban an IP address if too many login attempts are made from it?

Since an IP address does not necessarily represent a specific device, but probably a whole network/company/etc. does it at all make sense to block an IP address if there is a significant amount of ...
-2
votes
2answers
150 views

A Graphical Two-Step Authentication System [duplicate]

Changes made to system proposed in Two-factor authentication Without Mobile Phone: In previous system, shoulder surfing would reveal the user’s pre-decided image. In the current system, end image ...
2
votes
1answer
79 views

How do Client-specific keys and Certificates work?

I have clients that communicates with my server. Clients sends it unique id (guid) to server with its request over a secure https channel. Also to increase security I use my own private-public key ...
1
vote
1answer
1k views

How can a gmail recipient open email in two different countries, at the same time?

I sent an email to person in Russia, and tracked it with Right Inbox, when the email is opened I get notified. The problem is I get 2 different IP addresses, one in Russia, and one in the US, both ...
3
votes
1answer
1k views

“Extended Protection” primer and implementation guide to prevent MITM

Extended Protection (link) (link) is a feature in Windows 7 and Windows 2008 R2 that prevents certain MITM attacks. Does anyone have a primer (or explanation in plain English) what this feature is, ...
2
votes
1answer
79 views

Is TLS enough to prevent eavesdropping? [duplicate]

Is it enough to use only SSL/TLS for client-server application with authentication, registration and data transmission (like chat)? If it is not what I also need to use?
1
vote
2answers
95 views

Circumventing disadvantage of IP-based account lockout

So we're trying to prevent brute-force attacks on our web server login page--currently we just do IP-based locking if x failed attempts from IP address Y occur over z time period. After a security ...
0
votes
0answers
82 views

How to associate an oAuth token with a particular user. Is this possible?

We have HTTP Rest services and SignalR (aka Web sockets, server send events, etc) for cases in which we need to push data from the server to the Web UI . We are currently using the built in tools that ...
4
votes
2answers
80 views

FIDO: what is the benefit of the challenge parameter?

In the enrollment stage an attacker could intercept the message and answer with a signature based on the correct challenge. I know that normally you include a symmetric secret in such a challenge, but ...
1
vote
0answers
39 views

authentication token not stored in DB

I am implementing a webserver and the guideline I am following suggests: - to create token by a Serializer that takes the IdUser, a symmetric key and an expiry date - provide it to the user but not ...
1
vote
0answers
108 views

Is generating custom authentication token for WCF service requests a good practice?

I have public WCF web service which works over https. There are lots of technical restrictions on client side, so I can't use any advanced schemes like oauth. I have registered users and some of them ...
0
votes
0answers
40 views

Additional security for services hosted on a 2FA or Multi-Factor Authenticated Network

I am aiming to lock down a web service that accesses other services and has a publicly facing UI. I have a hosted service on a network that requires 2-factor authentication to access. This service's ...
0
votes
1answer
147 views

HMAC based algorithm for publicly sharing authenticated messages

I am trying to design an algorithm for publicly sharing authenticated messages. Obviously, asymmetric public/private key schemes do this, but I want to avoid the requirement that users have to keep ...
3
votes
1answer
67 views

Is it possible to restrict a client-side certificate (for web auth) valid only for a given site name?

If I have 2 websites, a.example.com and b.example.com. Those sites use TLS and SNI, and require client authentication with certificates created with my own CA. The use case is that some clients have ...
0
votes
3answers
144 views

What is a good way to authenticate a user to websites and applications with a smart phone?

What would be a good way to authenticate a user to authenticate to websites and applications over a smart phone? By good, I mean that it is both secure, and user-friendly. Passwords don't seem to be ...
1
vote
1answer
107 views

How do MACs provide authenticity?

I don't see how they're different then hash functions. Couldn't Alice use Bob's key to produce a MAC and send the message to Jim.
0
votes
1answer
124 views

Can Google's administrators be trusted with Google Authenticator? [duplicate]

Suppose there is an evil Google administrator who has full access to every server or network at Google. Will such a person be able to abuse the Google Authenticator technology to gain access to ...
0
votes
1answer
198 views

Drawbacks of using ADFS for SSO for external users

Is there any drawback for creating a separate AD forest for external users of organization to authenticate them to access some web applications? Is there any performance and synchronization issues ...
0
votes
1answer
68 views

How Google Authenticator in Android mobile identifies this is the right SSH server?

I am new to Google Authenticator mechanism. I gone the basics of mechanism but I couldn't understood what logic behind that to make a connection to the Linux machine. I have a Linux which have no ...
3
votes
1answer
249 views

Best practices for passwords on registration?

I have a website which users register an account. On the registration field, the form fields are: Name Email Confirm email Username But there is no password field. When they hit submit, they are ...