Comparition of OAuth and OAuth 2.0 are both open authorization protocols, but they differ significantly in terms

1. Protocol Version

• OAuth (1.0): First version of the protocol, focused on providing secure access delegation.
• OAuth 2.0: A complete redesign of OAuth 1.0, with enhancements to security, flexibility, and ease of use.

2. Complexity

• OAuth: More complex due to its reliance on cryptographic signing of requests. Every API call had to be signed using HMAC or RSA.
• OAuth 2.0: Simpler and more developer-friendly. It uses tokens (bearer tokens) for access without requiring cryptographic signing of each request.

3. Security Mechanism

• OAuth: Security relies heavily on cryptographic signatures for request verification. It does not support HTTPS natively, but HTTPS is often used alongside for additional security.
• OAuth 2.0: Emphasizes the use of HTTPS for secure communication and shifts focus from signing requests to token-based security.

4. Tokens

• OAuth:
  • Tokens are temporary credentials obtained during the handshake process.
  • Requires cryptographic methods for verification.
• OAuth 2.0:
  • Introduces different types of tokens:
    • Access Tokens: Used to access protected resources.
    • Refresh Tokens: Used to obtain a new access token when the current one expires.
  • Tokens are bearer tokens, which means anyone holding them can use them without extra verification.

5. Client Types

• OAuth: Supports only server-to-server communication and doesn’t differentiate between client types.
• OAuth 2.0: Introduces different client types:
  • Confidential Clients: Applications capable of keeping credentials secure (e.g., server-side apps).
  • Public Clients: Applications unable to keep credentials secure (e.g., mobile apps or single-page applications).

6. Authorization Flows

• OAuth:
  • Primarily uses a three-legged approach for authorization:
    1. Obtain request token.
    2. User authorizes access.
    3. Exchange request token for access token.
• OAuth 2.0:
  • Introduces multiple authorization flows tailored for different use cases:
    1. Authorization Code Flow: Best for server-side apps.
    2. Implicit Flow: Designed for browser-based apps (now discouraged due to security risks).
    3. Resource Owner Password Credentials Flow: For trusted clients (also discouraged).
    4. Client Credentials Flow: For server-to-server communication.
    5. Device Code Flow: For devices with limited input capabilities.

7. Backward Compatibility

• OAuth: Not backward-compatible with OAuth 2.0.
• OAuth 2.0: A complete departure from OAuth 1.0. They are distinct protocols.

8. Use Cases

• OAuth: Primarily used for web applications where secure request signing is critical.
• OAuth 2.0: Designed for modern use cases, including mobile apps, single-page applications, and IoT devices.

9. Adoption

• OAuth: Less popular now and mostly replaced by OAuth 2.0.
• OAuth 2.0: Widely adopted by major platforms like Google, Facebook, Microsoft, and others.