Helper Functions

OAUTH PKCE code_verifier and code_challenge Generator for IE 11 and Modern Browsers

A small (409-Byte gzipped) zero-dependency helper function for generating a high-entropy cryptographic random "code_verifier" (using Web Crypto API) and its "code_challenge" based on RFC 7636. (i.e. BASE64URL-ENCODE(SHA256(ASCII(code_verifier))))