PkceGeneration

PkceGeneration.cs

private async Task HandleChallengeAsyncInternal(AuthenticationProperties properties)
{
    // code omitted 
    if (Options.UsePkce && Options.ResponseType == OpenIdConnectResponseType.Code)
    {
        var bytes = new byte[32];
        RandomNumberGenerator.Fill(bytes);
        var codeVerifier = Base64UrlTextEncoder.Encode(bytes);

        // Store this for use during the code redemption. See RunAuthorizationCodeReceivedEventAsync.
        properties.Items.Add(OAuthConstants.CodeVerifierKey, codeVerifier);

        var challengeBytes = SHA256.HashData(Encoding.UTF8.GetBytes(codeVerifier));
        var codeChallenge = WebEncoders.Base64UrlEncode(challengeBytes);

        message.Parameters.Add(OAuthConstants.CodeChallengeKey, codeChallenge);
        message.Parameters.Add(OAuthConstants.CodeChallengeMethodKey, OAuthConstants.CodeChallengeMethodS256);
    }
    // code omitted 
}