Understanding Authorization code flow with PKCE

OAuth is a widely used protocol for identity federation, enabling social login flows, but it presents security concerns in mobile and embedded applications due to the potential exposure of client credentials. The Proof Key for Code Exchange (PKCE) method addresses these concerns by eliminating the need for client secrets and introducing a code_verifier and code_challenge, which ensure that only the original client can exchange an authorization code for an access token. PKCE enhances security by requiring this additional verification step, effectively preventing attackers from using intercepted authorization codes. This improvement is especially crucial as the use of single-page applications and embedded systems becomes more prevalent.