Microsoft.Owin.Security.OAuth.OAuthBearerAuthenticationMiddleware Warning: 0 : invalid bearer token received

Question

I'm getting this warning each time a user tries to access a protected api endpoint. The authentication works out fine and user is seemingly authenticated but I've been unable to figure out why this error keeps on happening. I'm running this on a localhost dev server with no https/ssl enabled. I might be missing a step not really sure here. I implemented token authentication as well as refresh tokens using custom providers. Then implemented a custom jwt format for generating the tokens.

This is the warning in the Application Output Log:

Microsoft.Owin.Security.OAuth.OAuthBearerAuthenticationMiddleware Warning: 0 : invalid bearer token received

SimpleJWTFormat.cs : This specifies the format for the jwt token

public class SimpleJwtFormat : ISecureDataFormat<AuthenticationTicket>
{

    private readonly string _issuer = string.Empty;

    public SimpleJwtFormat(string issuer)
    {
        _issuer = issuer;
    }

    public string Protect(AuthenticationTicket data)
    {
        if (data == null)
        {
            throw new ArgumentNullException("data");
        }

        string audienceId = ConfigurationManager.AppSettings["as:AudienceId"];

        string symmetricKeyAsBase64 = ConfigurationManager.AppSettings["as:AudienceSecret"];
        var keyByteArray = TextEncodings.Base64Url.Decode(symmetricKeyAsBase64);

        //var signingKey = new HmacSigningCredentials(keyByteArray);
        var securityKey = new Microsoft.IdentityModel.Tokens.SymmetricSecurityKey(keyByteArray);
        securityKey.KeyId = ConfigurationManager.AppSettings["as:AudienceId"];

        var signingCredentials = new Microsoft.IdentityModel.Tokens.SigningCredentials(securityKey, SecurityAlgorithms.HmacSha256Signature);

        var issued = data.Properties.IssuedUtc;

        var expires = data.Properties.ExpiresUtc;

        var token = new JwtSecurityToken(_issuer, audienceId, data.Identity.Claims, issued.Value.UtcDateTime, expires.Value.UtcDateTime, signingCredentials);
        //token.SigningKey = securityKey;

        var handler = new JwtSecurityTokenHandler();

        var jwt = handler.WriteToken(token);
        return jwt;
    }

    public AuthenticationTicket Unprotect(string protectedText)
    {
        string symmetricKeyAsBase64 = ConfigurationManager.AppSettings["as:AudienceSecret"];
        string audienceId = ConfigurationManager.AppSettings["as:AudienceId"];

        var keyByteArray = TextEncodings.Base64Url.Decode(symmetricKeyAsBase64);
        var signingKey = new Microsoft.IdentityModel.Tokens.SymmetricSecurityKey(keyByteArray); 

        var tokenValidationParameters = new TokenValidationParameters
        {
            ValidAudience = audienceId,
            ValidIssuer = _issuer,
            IssuerSigningKey = signingKey,
            ValidateLifetime = true,
            ValidateAudience = true,
            ValidateIssuer = true,
            RequireSignedTokens = true,
            RequireExpirationTime = true,
            ValidateIssuerSigningKey = true
        };


        var handler = new JwtSecurityTokenHandler();
        SecurityToken token = null;

        // Unpack token
        var pt = handler.ReadToken(protectedText);
        string t = ((JwtSecurityToken)pt).RawData;

        var principal = handler.ValidateToken(t, tokenValidationParameters, out token);
        var identity = principal.Identities;

        return new AuthenticationTicket(identity.First(), new AuthenticationProperties());
    }
}

Answer 1

Issue was I didn't call app.UseOAuthBearerAuthentication in the Startup.cs file and specify the custom token format.

app.UseOAuthBearerAuthentication(new OAuthBearerAuthenticationOptions()
{
  AccessTokenFormat = _tokenFormat
});