Understanding Digital Identity, Encryption, and OAuth 2.0 vs OIDC

Introduction In today’s digital era, grasping the concepts of digital identity, cryptography, and authentication protocols is vital. This article seeks to illuminate these subjects and deliver a comprehensive exploration.

Digital Identity: Navigating the Online Realm In the virtual world, digital identity serves as a distinct representation of an entity, whether it’s an individual, organization, or device. Just as in the physical realm where your name, photograph, and personal details identify you, your digital identity encompasses unique digital attributes, including usernames, email addresses, biometric data, and digital certificates.

These digital identifiers play a crucial role in establishing and validating your identity online, enabling you to access digital services securely and engage in various online activities.

This parallel between physical and digital identity underscores the significance of reliable and secure identification methods in both domains, which can manifest as usernames, emails, public keys, or even biometric data.

Encryption vs. Hashing: Technical Comparison Encryption:

  • Converts plain text into cipher text using a mathematical algorithm and an encryption key.
  • A two-way process.
  • Unlike hashing, it doesn’t produce a fixed-length output.


  • Converts plain text into a fixed-length string of characters called a hash.
  • Should be a one-way process, meaning it can’t be easily reversed to obtain the original input.
  • Used for data integrity checks.
  • Produces a fixed-length output.

Let’s address a few questions:

Is Bcrypt hashing or encrypting? Answer: Despite its name suggesting encryption, Bcrypt is hashing.

Is Base64 hashing or encrypting? Answer: Neither, it’s encoding. Base64 is a technique used to represent binary data in an ASCII string format, commonly used for encoding images in email attachments or embedding binary data in URLs.

Authentication vs. Authorization: Distinguishing the Roles Authentication: The process of verifying if a user is who they claim to be.

Authorization: The process of confirming whether the user has permission to access the desired resources.

Token: The Key to Access Tokens play a pivotal role in managing access and identity in the digital world. They act as data representations of a user’s identity or provide access to specific resources.

Various types of tokens are available, including access, refresh, session, ID, and CSRF. Each of these is discussed below:

Access Token: Clients use this token to access the Resource Server (API). They typically have a short lifespan, valid for a few hours or a day. Since they have a short duration, they can’t be revoked; you must wait for them to expire. For added security, consider setting a shorter timeout, such as one hour.

Refresh Token: Clients use the refresh token to obtain a new access token. These tokens have a longer lifespan, ranging from days to months or even years, and they can be revoked at any time.

Session Token: Used to maintain stateful interactions between the client and server.

ID Token: Exclusively used for authentication with OpenID Connect (OIDC).

CSRF Token: Employed to prevent a specific type of attack where a user is manipulated into taking actions on a different website without their knowledge.

It’s important to note that tokens don’t have to be in the form of JWTs (JSON Web Tokens). While JWTs are popular due to their compact size and self-contained nature, other options are available.

OAuth 2.0 and OIDC: Unraveling Their Roles OAuth 2.0 and OpenID Connect (OIDC) serve distinct purposes. OAuth 2.0 primarily functions as an authorization framework, while OIDC focuses on authentication. OIDC operates on top of OAuth 2.0, which, in turn, builds on HTTP.

OAuth 2.0 and OpenID Connect (OIDC) are separate technologies designed for different functions.

OAuth 2.0: An open-standard authorization framework, not an independent service, enabling delegated permissions and resource access. It’s often confused with Auth0, which is a product.

OAuth 2.0 Roles:

  • Resource Owner (RO): An entity that can grant access to a protected resource.
  • Client: The application seeking access to protected data on behalf of the resource owner.
  • Resource Server (RS): The server hosting the protected resource.
  • Authorization Server (AS): The server responsible for authenticating the resource owner and granting access to the client.
  • Authorization Grant: A credential representing the resource owner’s consent.
  • Redirect URI: The URL where the authorization server sends users after granting permission.
  • Access Token: A credential confirming authorization but with limitations defined in the scope.
  • Refresh Token: Optionally used to obtain a new access token.

OAuth 1.0 vs. OAuth 2.0 Simplicity: Version 1.0 was complex due to cryptographic signatures for each request. Support: While initially tailored for server-to-server communication, version 1.0 evolved to accommodate a wider range of clients, including mobile apps, web apps, and IoT devices. Native Support: Version 1.0 was not well-suited for native mobile applications, but version 2.0 addressed this with PKCE (Proof Key for Code Exchange). Token-Based: Version 2.0 adopted a bearer token approach, simplifying authentication compared to version 1.0’s signature-based method. Scope: Version 2.0 introduced scopes for managing permissions and access control more precisely.

OAuth Flows OAuth flows or grants are mechanisms for clients to obtain credentials from the authorization server (AS) to access the resource server (RS). Various flows are tailored for different scenarios, including the Auth Code Flow, Implicit Flow, Client Credential Flow, Auth Code with PKCE, and Resource Owner Password Grant Flow.

Auth Code Flow:

  • Usage: Suitable for web or server-side apps capable of securely storing client secrets.
  • Steps: Client redirects the resource owner to the AS endpoint, resource owner authenticates and authorizes the client access request, AS responds with an authorization code, client exchanges the authorization code for an access token.

Implicit Flow:

  • Usage: Suitable for client-side apps that can’t securely store client secrets.
  • Steps: Client redirects to the resource owner’s AS endpoint, resource owner authenticates and authorizes the client access request, AS responds with an access token.

Client Credential Flow:

  • Usage: For server-to-server communication (back channel only), where the client application can securely store its own credentials.
  • Steps: The client application sends its credentials (client ID and client secret) directly to the AS’s token endpoint, the AS verifies the credentials and issues an access token.

Auth Code With PKCE:

  • Usage: Enhanced version of the Auth Code Flow designed to protect against specific attacks.
  • Steps: Similar to the Auth Code Grant, but with an additional step to generate a challenge and prove possession of the original code during a token exchange.

Resource Owner Password Grant Flow:

  • Usage: Typically used when the client application has direct access to the user’s credentials and can securely store them. Often seen in legacy or internal systems.
  • Steps: The client application prompts the user for their username and password, sends the credentials directly to the AS’s token endpoint, the AS validates the credentials and issues an access token.

OIDC (OpenID Connect) OpenID Connect focuses on authentication and provides a standardized approach to areas where OAuth 2.0 has room for interpretation, such as scope and endpoints. It extends OAuth 2.0, enabling clients to verify the end user’s identity and obtain basic profile information.

Key Points about OIDC:

  • OIDC extends OAuth 2.0.
  • It adds a simple identity layer to OAuth 2.0.
  • Clients can verify the end user’s identity and obtain basic profile information.
  • OIDC often uses JSON Web Tokens (JWTs).

OAuth mainly handles resource sharing and access, while OIDC specializes in user authentication, aiming to provide identity verification across multiple websites.

When using OIDC to log in to a website, you are redirected to the OpenID site for authentication, and after a successful login, you return to the original website with a secure JWT token for further authentication and authorization.

When to Use OIDC and When to Use OAuth 2.0 The choice between OpenID Connect (OIDC) and OAuth 2.0 depends on your application’s specific requirements. Here are some use cases and their recommended choices:

Simple login authentication:

  • Identity: OIDC
  • Type: Authentication

Single sign-on across sites:

  • Identity: OIDC
  • Type: Authentication

Mobile app login:

  • Identity: OIDC
  • Type: Authentication

Delegated authorization:

  • Identity: OAuth 2.0
  • Type: Authorization

Recommended Flow Types for Use Cases Here are recommended flow types based on various use cases:

Web apps accessing APIs (Frontend + Backend):

  • Flow type: Authorization Code Flow
  • Suitable for traditional web applications with a backend server, and native apps like mobile apps.

Mobile apps:

  • Flow type: Authorization Code Flow with Proof Key for Code Exchange (PKCE).

Single-Page Applications (SPAs):

  • Flow type: Authorization Code Grant Flow.

CLI apps or Daemons:

  • Flow type: Client Credentials Flow.

API-to-API communication:

  • Flow type: Client Credential Flow.

SSO with third-party services:

  • Flow type: Depends on integration requirements (e.g., OKTA/Auth0/PingID).

In conclusion, understanding the distinct use cases of OAuth 2.0 and OIDC is crucial for effectively navigating the digital landscape. It’s about choosing the right tool for the job to ensure the security and functionality of your applications.

We hope this overview of digital identity, encryption, OAuth 2.0, and OIDC has provided valuable insights into securing your online interactions. Your understanding of these concepts is essential in today’s digital environment.

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