RFC 7636 ยง4.2, S256 method: code_challenge = BASE64URL-ENCODE(SHA256(ASCII(code_verifier))). code_verifier is already restricted to the unreserved-character subset of ASCII, so TextEncoder (UTF-8) and ASCII() agree byte-for-byte here.
code_challenge = BASE64URL-ENCODE(SHA256(ASCII(code_verifier)))
code_verifier
TextEncoder
ASCII()
RFC 7636 ยง4.2, S256 method:
code_challenge = BASE64URL-ENCODE(SHA256(ASCII(code_verifier))).code_verifieris already restricted to the unreserved-character subset of ASCII, soTextEncoder(UTF-8) andASCII()agree byte-for-byte here.