MsalProvider.cs ctors convert scope strings to lowercase but should not do that!

[tnsturm]

Toolkit Version 7.1.1

MsalProvider.cs Contructors convert the scope arrays to lowercase:

Scopes = scopes.Select(s => s.ToLower()).ToArray() ?? new string[] { string.Empty };

It should not do this because OpenID specs define scopes as CASE SENSITIVE.
https://openid.net/specs/openid-connect-core-1_0.html#ScopeClaims
"Multiple scope values MAY be used by creating a space delimited, case sensitive list of ASCII scope values."

https://tools.ietf.org/html/rfc6749#section-3.3
"The value of the scope parameter is expressed as a list of space-delimited, case-sensitive strings. The strings are defined by the authorization server. If the value contains multiple space-delimited strings, their order does not matter, and each string adds an additional access range to the requested scope."

I'm running an .NET Core 6 Azure Web App Api with an case sensitive scope in the AAD app registration. Using standard MSAL PublicClientApplication runs fine with that. Using the MsalProvider wrapper of the community toolkit breaks this, because the "lowercased" scope is not accepted by Microsoft.IdentityModel.Tokens.SecurityToken:

IDX10214: Audience validation failed. Audiences: 'https://abce.de/webapp-abcd.azurewebsites.net'. Did not match: validationParameters.ValidAudience: 'https://abce.de/WebApp-abce.azurewebsites.net'

Please not the uppercase 'W' in the scope.

Earlier versions of MSAL also had that bug and fixed it:
AzureAD/microsoft-authentication-library-for-objc#395
AzureAD/microsoft-authentication-library-for-js#1922

Best Regards,
Torsten

[ghost]

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