Proof Key for Code Exchange (PKCE) is a security extension for OAuth 2.0 that enhances authorization code flows.
Description
PKCE, or Proof Key for Code Exchange, is an extension to the OAuth 2.0 protocol specifically designed to improve the security of public clients, such as mobile and single-page applications. Originally developed to mitigate the risk of authorization code interception attacks, PKCE adds an extra layer of security by requiring the client to generate a unique code verifier and a derived code challenge before initiating the authorization flow. During the authorization request, the code challenge is sent to the authorization server, and the code verifier is used later when redeeming the authorization code. This process ensures that even if an attacker intercepts the authorization code, they cannot exchange it for an access token without the corresponding code verifier. PKCE is widely supported by major identity providers like Google, Microsoft, and GitHub, and has become a recommended practice for secure OAuth implementations, especially for applications that cannot safely store client secrets.
Examples
- Google uses PKCE in its OAuth 2.0 implementation for Android and iOS applications to secure user authentication.
- GitHub's OAuth integration employs PKCE to protect the authorization flow for third-party applications accessing user data.
Additional Information
- PKCE is now considered a best practice for all OAuth 2.0 implementations, not just public clients.
- The use of PKCE significantly reduces the risk of phishing attacks and improves overall user data security.