PKCE Generator

PKCE Generator produces a compliant pair of PKCE parameters: code_verifier and code_challenge. It can generate a cryptographically random verifier when omitted and derive the challenge using the selected method. The primary method, S256, computes a SHA-256 digest of the verifier and encodes it with base64url without padding to form the code_challenge. The plain method returns the verifier as the challenge, though it is less secure and not recommended for public clients. The tool enforces PKCE length rules (43–128 characters) and uses an allowed character set to ensure compatibility with OAuth libraries. It outputs the final verifier, the derived challenge, and the chosen method, making it straightforward to integrate into client-side code or CI pipelines. By separating input validation, cryptographic computation, and encoding, this tool helps maintain security posture while reducing manual scripting. Use cases include native mobile apps initiating the authorization flow, single-page apps that require a secure exchange, and server-side clients that need to demonstrate correct parameter generation. Unique value lies in strict PKCE adherence, deterministic outputs for given inputs, and clear error reporting for non-compliant data. Core features cover input flexibility, method selection, secure generation, and explicit outputs suitable for immediate use in OAuth configurations.