Authentication Protocols User Authentication

Quick Guide to the Top User Authentication Protocols & Methods

User authentication is the process of ensuring the right people have access to the right resources by verifying their identity. 

Although it sounds straightforward, IT departments face numerous challenges in using it to secure data, networks, and apps. 

According to IT Governance, in March 2023, 100 publicly disclosed security incidents resulted in 41.9 million breached records.     

Today’s article separately discloses secure authentication methods & website authentication protocols. And along with what they are. 

So, if you are a business owner looking forward to implementing authentication correctly, we have you covered.

What is Password Authentication Protocol?

A password authentication protocol is the most basic method to authenticate a user. It is simply a shared secret that both parties have. And it is important that encryption techniques are used to protect against unauthorized interception during the transmission of this shared secret.

Since this protocol is so simple it has widespread adoption, transparency, and an uncomplicated design.

However, password authentication has a fundamental flaw, in order to authenticate with a password you must reveal the password. Which makes it easy for attackers to trick users into revealing their secret password through social engineering and phishing attacks.

6 Top Website Authentication Protocols

When executing authentication, system designers have tons of protocols available to them. Here are the top six: 


FIDO2 is a standard developed by the FIDO Alliance that enables passwordless authentication using public key cryptography from a local device, such as a token or smartphone, via the Web Authentication API and Client-to-Authenticator Protocol. 

FIDO2 provides a secure, convenient, and scalable way for users to authenticate to online services using unique cryptographic login credentials for every site. The specifications behind FIDO2 are the World Wide Web Consortium’s Web Authentication (WebAuthn) and FIDO Alliance’s Client-to-Authenticator Protocol (CTAP). 

FIDO2 aims to eliminate the use of passwords over the internet so users can say goodbye to common online attacks.


OpenID is an open-source protocol for authentication and single sign-on (SSO). The protocol is built on top of the OAuth 2.0 authorization framework. Instead of signing up/logging in to individual websites using email, users get redirected to the OpenID site for login. 

OAuth2 is an open standard token-based authorization protocol that authenticates limited access to the user on a specific online account. It enables services to access user resources and data without exposing their credentials. 

High-profile companies like Facebook, Twitter, and Google use OAuth2 to authorize API calls with limited access tokens.


SAML, short for Security Assertion Markup Language, is an open standard protocol. It exchanges authentication and authorization data between two parties, using an identity and service provider, based on XML format. 

SAML simplifies the authentication process and enables users to access multiple applications within a domain. It passes information through signed XML documents and is a product of the OASIS Security Services Technical Committee.


LDAP, or Lightweight Directory Access Protocol, is an open, cross-platform software protocol for AD directory services. The protocol helps locate data and files of individuals, organizations, and devices on public or corporate networks. It is commonly used as Directories-as-a-Service to access and maintain distributed directory information services. 

LDAP accesses and maintains static data, including usernames, passwords, email addresses, and printer connections. It is also used for authentication to verify credentials with a directory service. This protocol works by binding an LDAP user to an LDAP server and processing client requests for information.


Kerberos is a network authentication protocol for verifying clients/servers requests using a cryptographic key. It is compatible with all operating systems, including Windows, macOS, Linux, and Active Directory. 

Licensed under MIT, Kerberos provides authentication and a ticket-granting service. The protocol uses symmetric keys from a centralized key distribution center to authenticate clients over insecure networks. 

Kerberos provides strong authentication for client/server applications and is available in many commercial products. Despite its protections, Kerberos experienced issues with a system update in 2020.


RADIUS is a client-server protocol that provides centralized Authentication, Authorization, and Accounting (AAA) management for users who connect and use a network service. It encrypts user credentials and compares them to a locally stored or external database. 

The RADIUS protocol is triggered when a user requests access to network resources and may challenge or reject a user. RADIUS allows individual users to be granted restricted access without affecting others. It is mainly used for remote access across multiple networks.

What are User Authentication Methods?

User authentication methods use the underlying protocols we have discussed above to implement ways to verify user credentials. 

Top 3 Secure Authentication Methods

2 Factor/Multi-Factor Authentication

2FA/MFA or Multi-Factor Authentication grants access to a user only after successfully presenting two or more pieces of evidence (or factors) to an authentication mechanism.

  • Knowledge (something the user and only the user knows)
  • Possession (something the user and only the user has)
  • Inherence (something the user and only the user is). 

Examples of these factors include but aren’t limited to a password, an OTP, and a biometric scan.

Authentication with Passkeys

Passkeys is a new standard by FIDO that promotes passwordless authentication. It provides a fast, easy, and secure way to sign in to apps and websites.

A Passkey-supported service uses biometrics like face, fingerprint scan, or PIN that a user uses to unlock their device. Then, instead of creating a traditional username and password, the site generates cryptographic key pairs.

Passkeys provide strong, non-guessable, and non-reusable credentials. They are only linked with the service they were created for. And it never stores private keys on servers.       


Ever seen a sign-in with Google, Microsoft, or Apple button on a website? That’s OIDC.  Powered by OpenID, OIDC, or OpenID Connect lets users seamlessly authenticate to a service by trusting a single identity provider.

At Vault Vision, we support Google, Microsoft, and Apple OIDC Auths. And we are officially certified by OIDC to provide its services.

What is the Most Secure Authentication Method

Biometrics is considered one of the most secure authentication methods, relying on the inherence factor. Unlike passwords, your facial features, fingerprints, voice, and retina characteristics are unique, making them hard to steal.

Combine biometrics with Multi-Factor Authentication, where a user has to provide at least two additional verifications, and things get pretty secure.

Other technologies like Passkeys and OIDC are also catching up to pave the way to a passwordless future. And they also use the power of biometrics.

However, the answer to which authentication method is the most secure also relies on the following:

  • What are the Needs of your companies? 
  • Can your current Infrastructure handle the change? 
  • Are you willing to provide the Training to get things going?
  • Is the system capable of keeping up with the Future

Final Words

We hope that after reading this piece, the buzzwords in the authentication world won’t be foreign to you anymore. This guide helped you learn about the top secure authentication methods and protocols.

At Vault Vision, we provide all the advanced secure authentication methods, including MFA, Passkeys, OIDC, SSO, and more. Start your free trial with expert help without entering your credit card details.

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