What is Authentication? The Ultimate Authentication Playbook

With the rise of credential stuffing and similar attack methods, simple username and password authentication is not enough to deter bad actors. 

 According to the Verizon Data Breach Investigations Report, there were over 55,000 security incidents and 2,200 confirmed data breaches in 2018, with a whopping 81% of those incidents being tied to stolen or weak passwords.

With the proliferation of data breaches and loss of consumer trust, enterprises must take a second look at the security posture of their web applications, starting with an exploration of more secure authentication methods.

What does authentication mean? What is multi-factor authentication vs. two-factor authentication? In this post, I will break down some of the most common authentication methods we see today, as well as some tips on how to best implement them.

Authentication vs Authorisation

To be clear, when we talk about authentication, we are talking about the act of verifying an identity—making sure users are who they say they are. The most common and simplest example of authentication is using a username and password to access an application, like your bank account.

But often times when people talk about app security, they confuse the concepts of Authentication and Authorisation, or use them interchangeably. But they are actually independent and orthogonal ideas, and understanding the difference between them is critical.

Very crudely speaking, in terms of web apps, authentication is when the system checks login credentials to see if it recognises a user, and confirm that they should be logged in. Whereas authorisation is when the system looks up within the access control permissions whether or not to allow the user to view, edit, delete or create content.


Description of Authentication and Authorisation

With a better understanding of what authentication means, let’s move on to the big question...

What are the different types of authentication methods?

Single Factor Authentication

Also known as primary authentication, this is the simplest and most common form of authentication. Single Factor Authentication requires, of course, only one authentication method such as a password, security pin, PIV card, etc. to grant access to a system or service.

While these methods score high on usability and familiarity, they are typically associated with poor security and can be easily guessed or stolen via data breaches, phishing or using keyloggers.

2nd Factor Authentication

Adding a layer of complexity, 2FA requires a second factor to verify a user’s identity. Common examples include tokens generated by a registered device, One Time Passwords, or PIN numbers. The mere presence of two authentication methods improves your security posture significantly—in fact, according to research from Symantec, 80% of data breaches can be prevented by 2FA.

While the security benefits of 2FA are well documented, adoption has been a widespread problem. When Google first introduced the option to have two authentication methods applied to their accounts, less than 10% of users adopted 2FA over the course of over 7 years. According to Google one of the reasons why they did not require 2FA was due to the inconvenience it caused users, noting that >10% of users who tried 2FA, failed to enter the SMS authentication code correctly.

Multi-Factor Authentication

Multi-Factor Authentication (MFA) is the most sophisticated authentication method that leverages 2 or more independent factors to grant user access to a system. In typical scenarios, MFA methods leverage at least 2 or 3 of the following categories.

  1. Something you know - a password or a pin
  2. Something you have - mobile phone or a security token
  3. Something you are - fingerprint or FaceID
  4. Something you do - typing speed, locational information etc.



Different methods of authentication


Authentication Method Protocols

Authentication methods that leverage usernames/passwords and/or multi-factor are generally considered secure. But there are authentication scenarios that break the bidirectional model of authentication.

One common example is when you access a third party service from the confines of an existing service (either from a mobile device, another website, or desktop app). For example, when linking your bank accounts to a third party wealth management platform.

In such scenarios, it is not secure or prudent to share your authentication method with the third party application, which might store the credentials. Storing credentials increases the attack surface and makes a user vulnerable to credential breach attacks.

There are several authentication protocols you can implement to prevent yourself from exposing your user data to attackers, including Oauth, OpenID, SAML and FIDO.

What about API Authentication?

In the age of the API economy, API’s handle large volumes of data and add a new dimension to the security surface of an online service. While there are many API authentication methods, most of them can be categorised within one of three methods:

HTTP Basic Auth

Using this approach, a user agent simply provides a username and password to prove their authentication. This approach does not require cookies, session ID’s, or login pages because it leverages the HTTP header itself. While simple to use, this method of authentication is vulnerable to attacks that could capture the user’s credentials in transit.

API Keys

An API key is an identifier meant to identify the origin of web service requests (or similar types of requests). A key is generated the first time a user attempts to gain authorised access to a system through registration. From there, the API key becomes associated with a secret token, and is submitted alongside requests going forward. When the user attempts to re-enter the system, their unique key is used to prove that they’re the same user as before. This API Authentication Method is very fast and reliable, but is frequently misused. More importantly, this method of authentication is not a method of authorisation.


Oauth is one of the most secure methods of API authentication, and supports both authentication and authorisation. OAuth allows the API to authenticate by establishing scope, and can access the system or resource requested. This is fundamentally a very secure means of authenticating to your API.

Making authentication more about the user and less about the attacker

The authentication game is changing, big time. Biometric authenticators that are built into user devices such as FaceID, TouchID or Windows Hello will continue to shape how users authenticate into online services.

Forward-looking businesses will look beyond passwords and improve API authentication as a means of enhancing the user experience, reducing the success rates of phishing attacks. Attackers will no longer benefit from the weaknesses of passwords by incorporating more secure authentication methods.

To learn more on how Okta can help you deliver on the promise of better and secure authentication experience authentication page around Customer Identity.