private async Task <string> SerializeIdentityTokenAsync(
            ClaimsPrincipal principal, AuthenticationProperties properties,
            OpenIdConnectRequest request, OpenIdConnectResponse response)
        {
            // Replace the principal by a new one containing only the filtered claims.
            // Actors identities are also filtered (delegation scenarios).
            principal = principal.Clone(claim =>
            {
                // Never exclude the subject claim.
                if (string.Equals(claim.Type, OpenIdConnectConstants.Claims.Subject, StringComparison.OrdinalIgnoreCase))
                {
                    return(true);
                }

                // Claims whose destination is not explicitly referenced or doesn't
                // contain "id_token" are not included in the identity token.
                if (!claim.HasDestination(OpenIdConnectConstants.Destinations.IdentityToken))
                {
                    Logger.LogDebug("'{Claim}' was excluded from the identity token claims.", claim.Type);

                    return(false);
                }

                return(true);
            });

            // Remove the destinations from the claim properties.
            foreach (var claim in principal.Claims)
            {
                claim.Properties.Remove(OpenIdConnectConstants.Properties.Destinations);
            }

            var identity = (ClaimsIdentity)principal.Identity;

            // Create a new ticket containing the updated properties and the filtered principal.
            var ticket = new AuthenticationTicket(principal, properties, Options.AuthenticationScheme);

            ticket.Properties.IssuedUtc  = Options.SystemClock.UtcNow;
            ticket.Properties.ExpiresUtc = ticket.Properties.IssuedUtc +
                                           (ticket.GetIdentityTokenLifetime() ?? Options.IdentityTokenLifetime);

            ticket.SetUsage(OpenIdConnectConstants.Usages.IdentityToken);

            // Associate a random identifier with the identity token.
            ticket.SetTicketId(Guid.NewGuid().ToString());

            // Remove the unwanted properties from the authentication ticket.
            ticket.RemoveProperty(OpenIdConnectConstants.Properties.AccessTokenLifetime)
            .RemoveProperty(OpenIdConnectConstants.Properties.AuthorizationCodeLifetime)
            .RemoveProperty(OpenIdConnectConstants.Properties.ClientId)
            .RemoveProperty(OpenIdConnectConstants.Properties.CodeChallenge)
            .RemoveProperty(OpenIdConnectConstants.Properties.CodeChallengeMethod)
            .RemoveProperty(OpenIdConnectConstants.Properties.IdentityTokenLifetime)
            .RemoveProperty(OpenIdConnectConstants.Properties.RedirectUri)
            .RemoveProperty(OpenIdConnectConstants.Properties.RefreshTokenLifetime);

            ticket.SetAudiences(ticket.GetPresenters());

            var notification = new SerializeIdentityTokenContext(Context, Options, request, response, ticket)
            {
                Issuer = Context.GetIssuer(Options),
                SecurityTokenHandler = Options.IdentityTokenHandler,
                SigningCredentials   = Options.SigningCredentials.FirstOrDefault(key => key.Key is AsymmetricSecurityKey)
            };

            await Options.Provider.SerializeIdentityToken(notification);

            if (notification.HandledResponse || !string.IsNullOrEmpty(notification.IdentityToken))
            {
                return(notification.IdentityToken);
            }

            else if (notification.Skipped)
            {
                return(null);
            }

            if (!ReferenceEquals(ticket, notification.Ticket))
            {
                throw new InvalidOperationException("The authentication ticket cannot be replaced.");
            }

            if (notification.SecurityTokenHandler == null)
            {
                return(null);
            }

            // Extract the main identity from the principal.
            identity = (ClaimsIdentity)ticket.Principal.Identity;

            if (string.IsNullOrEmpty(identity.GetClaim(OpenIdConnectConstants.Claims.Subject)))
            {
                throw new InvalidOperationException("The authentication ticket was rejected because " +
                                                    "it doesn't contain the mandatory subject claim.");
            }

            // Note: identity tokens must be signed but an exception is made by the OpenID Connect specification
            // when they are returned from the token endpoint: in this case, signing is not mandatory, as the TLS
            // server validation can be used as a way to ensure an identity token was issued by a trusted party.
            // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation for more information.
            if (notification.SigningCredentials == null && request.IsAuthorizationRequest())
            {
                throw new InvalidOperationException("A signing key must be provided.");
            }

            // Store the "unique_id" property as a claim.
            identity.AddClaim(OpenIdConnectConstants.Claims.JwtId, ticket.GetTicketId());

            // Store the "usage" property as a claim.
            identity.AddClaim(OpenIdConnectConstants.Claims.Usage, ticket.GetUsage());

            // Store the "confidentiality_level" property as a claim.
            var confidentiality = ticket.GetProperty(OpenIdConnectConstants.Properties.ConfidentialityLevel);

            if (!string.IsNullOrEmpty(confidentiality))
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.ConfidentialityLevel, confidentiality);
            }

            // Store the audiences as claims.
            foreach (var audience in notification.Audiences)
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.Audience, audience);
            }

            // If a nonce was present in the authorization request, it MUST
            // be included in the id_token generated by the token endpoint.
            // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
            var nonce = request.Nonce;

            if (request.IsAuthorizationCodeGrantType())
            {
                // Restore the nonce stored in the authentication
                // ticket extracted from the authorization code.
                nonce = ticket.GetProperty(OpenIdConnectConstants.Properties.Nonce);
            }

            if (!string.IsNullOrEmpty(nonce))
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.Nonce, nonce);
            }

            if (notification.SigningCredentials != null && (!string.IsNullOrEmpty(response.Code) ||
                                                            !string.IsNullOrEmpty(response.AccessToken)))
            {
                using (var algorithm = OpenIdConnectServerHelpers.GetHashAlgorithm(notification.SigningCredentials.Algorithm))
                {
                    // Create an authorization code hash if necessary.
                    if (!string.IsNullOrEmpty(response.Code))
                    {
                        var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.Code));

                        // Note: only the left-most half of the hash of the octets is used.
                        // See http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken
                        identity.AddClaim(OpenIdConnectConstants.Claims.CodeHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                    }

                    // Create an access token hash if necessary.
                    if (!string.IsNullOrEmpty(response.AccessToken))
                    {
                        var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.AccessToken));

                        // Note: only the left-most half of the hash of the octets is used.
                        // See http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
                        identity.AddClaim(OpenIdConnectConstants.Claims.AccessTokenHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                    }
                }
            }

            // Extract the presenters from the authentication ticket.
            var presenters = notification.Presenters.ToArray();

            switch (presenters.Length)
            {
            case 0: break;

            case 1:
                identity.AddClaim(OpenIdConnectConstants.Claims.AuthorizedParty, presenters[0]);
                break;

            default:
                Logger.LogWarning("Multiple presenters have been associated with the identity token " +
                                  "but the JWT format only accepts single values.");

                // Only add the first authorized party.
                identity.AddClaim(OpenIdConnectConstants.Claims.AuthorizedParty, presenters[0]);
                break;
            }

            var token = notification.SecurityTokenHandler.CreateToken(new SecurityTokenDescriptor
            {
                Subject            = identity,
                Issuer             = notification.Issuer,
                SigningCredentials = notification.SigningCredentials,
                IssuedAt           = notification.Ticket.Properties.IssuedUtc?.UtcDateTime,
                NotBefore          = notification.Ticket.Properties.IssuedUtc?.UtcDateTime,
                Expires            = notification.Ticket.Properties.ExpiresUtc?.UtcDateTime
            });

            return(notification.SecurityTokenHandler.WriteToken(token));
        }
        private async Task <string> SerializeIdentityTokenAsync(
            ClaimsPrincipal principal, AuthenticationProperties properties,
            OpenIdConnectMessage request, OpenIdConnectMessage response)
        {
            try {
                // properties.IssuedUtc and properties.ExpiresUtc
                // should always be preferred when explicitly set.
                if (properties.IssuedUtc == null)
                {
                    properties.IssuedUtc = Options.SystemClock.UtcNow;
                }

                if (properties.ExpiresUtc == null)
                {
                    properties.ExpiresUtc = properties.IssuedUtc + Options.IdentityTokenLifetime;
                }

                properties.SetUsage(OpenIdConnectConstants.Usages.IdToken);

                // Replace the principal by a new one containing only the filtered claims.
                // Actors identities are also filtered (delegation scenarios).
                principal = principal.Clone(claim => {
                    // ClaimTypes.NameIdentifier and JwtRegisteredClaimNames.Sub are never excluded.
                    if (string.Equals(claim.Type, ClaimTypes.NameIdentifier, StringComparison.Ordinal) ||
                        string.Equals(claim.Type, JwtRegisteredClaimNames.Sub, StringComparison.Ordinal))
                    {
                        return(true);
                    }

                    // Claims whose destination is not explicitly referenced or
                    // doesn't contain "id_token" are not included in the identity token.
                    return(claim.HasDestination(OpenIdConnectConstants.ResponseTypes.IdToken));
                });

                var identity = (ClaimsIdentity)principal.Identity;

                // Create a new ticket containing the updated properties and the filtered principal.
                var ticket = new AuthenticationTicket(principal, properties, Options.AuthenticationScheme);

                var notification = new SerializeIdentityTokenContext(Context, Options, request, response, ticket)
                {
                    Confidential         = properties.IsConfidential(),
                    Issuer               = Context.GetIssuer(Options),
                    Nonce                = request.Nonce,
                    SecurityTokenHandler = Options.IdentityTokenHandler,
                    SigningCredentials   = Options.SigningCredentials.FirstOrDefault()
                };

                // If a nonce was present in the authorization request, it MUST
                // be included in the id_token generated by the token endpoint.
                // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
                if (request.IsAuthorizationCodeGrantType())
                {
                    // Restore the nonce stored in the authentication
                    // ticket extracted from the authorization code.
                    notification.Nonce = properties.GetNonce();
                }

                // While the 'sub' claim is declared mandatory by the OIDC specs,
                // it is not always issued as-is by the authorization servers.
                // When missing, the name identifier claim is used as a substitute.
                // See http://openid.net/specs/openid-connect-core-1_0.html#IDToken
                notification.Subject = identity.GetClaim(JwtRegisteredClaimNames.Sub) ??
                                       identity.GetClaim(ClaimTypes.NameIdentifier);

                // Only add client_id in the audiences list if it is non-null.
                if (!string.IsNullOrEmpty(request.ClientId))
                {
                    notification.Audiences.Add(request.ClientId);
                }

                if (!string.IsNullOrEmpty(response.Code))
                {
                    using (var algorithm = SHA256.Create()) {
                        // Create the c_hash using the authorization code returned by SerializeAuthorizationCodeAsync.
                        var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.Code));

                        // Note: only the left-most half of the hash of the octets is used.
                        // See http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken
                        notification.CHash = Base64UrlEncoder.Encode(hash, 0, hash.Length / 2);
                    }
                }

                if (!string.IsNullOrEmpty(response.AccessToken))
                {
                    using (var algorithm = SHA256.Create()) {
                        // Create the at_hash using the access token returned by SerializeAccessTokenAsync.
                        var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.AccessToken));

                        // Note: only the left-most half of the hash of the octets is used.
                        // See http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
                        notification.AtHash = Base64UrlEncoder.Encode(hash, 0, hash.Length / 2);
                    }
                }

                // Sets the default identity token serializer.
                notification.Serializer = payload => {
                    if (notification.SecurityTokenHandler == null)
                    {
                        return(Task.FromResult <string>(null));
                    }

                    if (string.IsNullOrEmpty(notification.Subject))
                    {
                        throw new InvalidOperationException(
                                  "A unique identifier cannot be found to generate a 'sub' claim. " +
                                  "Make sure to either add a 'sub' or a 'ClaimTypes.NameIdentifier' claim " +
                                  "in the returned ClaimsIdentity before calling SignIn.");
                    }

                    // Extract the main identity from the principal.
                    identity = (ClaimsIdentity)payload.Principal.Identity;

                    // Store the unique subject identifier as a claim.
                    identity.AddClaim(JwtRegisteredClaimNames.Sub, notification.Subject);

                    // Remove the ClaimTypes.NameIdentifier claims to avoid getting duplicate claims.
                    // Note: the "sub" claim is automatically mapped by JwtSecurityTokenHandler
                    // to ClaimTypes.NameIdentifier when validating a JWT token.
                    // Note: make sure to call ToArray() to avoid an InvalidOperationException
                    // on old versions of Mono, where FindAll() is implemented using an iterator.
                    foreach (var claim in identity.FindAll(ClaimTypes.NameIdentifier).ToArray())
                    {
                        identity.RemoveClaim(claim);
                    }

                    // Store the "usage" property as a claim.
                    identity.AddClaim(OpenIdConnectConstants.Extra.Usage, payload.Properties.GetUsage());

                    // Store the audiences as claims.
                    foreach (var audience in notification.Audiences)
                    {
                        identity.AddClaim(JwtRegisteredClaimNames.Aud, audience);
                    }

                    if (!string.IsNullOrEmpty(notification.AtHash))
                    {
                        identity.AddClaim("at_hash", notification.AtHash);
                    }

                    if (!string.IsNullOrEmpty(notification.CHash))
                    {
                        identity.AddClaim(JwtRegisteredClaimNames.CHash, notification.CHash);
                    }

                    if (!string.IsNullOrEmpty(notification.Nonce))
                    {
                        identity.AddClaim(JwtRegisteredClaimNames.Nonce, notification.Nonce);
                    }

                    // If the ticket is marked as confidential, add a new
                    // "confidential" claim in the security token.
                    if (notification.Confidential)
                    {
                        identity.AddClaim(new Claim(OpenIdConnectConstants.Extra.Confidential, "true", ClaimValueTypes.Boolean));
                    }

                    var token = notification.SecurityTokenHandler.CreateToken(
                        subject: identity,
                        issuer: notification.Issuer,
                        signingCredentials: notification.SigningCredentials,
                        issuedAt: payload.Properties.IssuedUtc.Value.UtcDateTime,
                        notBefore: payload.Properties.IssuedUtc.Value.UtcDateTime,
                        expires: payload.Properties.ExpiresUtc.Value.UtcDateTime);

                    if (notification.SigningCredentials != null)
                    {
                        var x509SecurityKey = notification.SigningCredentials.Key as X509SecurityKey;
                        if (x509SecurityKey != null)
                        {
                            // Note: unlike "kid", "x5t" is not automatically added by JwtHeader's constructor in IdentityModel for ASP.NET 5.
                            // Though not required by the specifications, this property is needed for IdentityModel for Katana to work correctly.
                            // See https://github.com/aspnet-contrib/AspNet.Security.OpenIdConnect.Server/issues/132
                            // and https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/issues/181.
                            token.Header[JwtHeaderParameterNames.X5t] = Base64UrlEncoder.Encode(x509SecurityKey.Certificate.GetCertHash());
                        }

                        object identifier;
                        if (!token.Header.TryGetValue(JwtHeaderParameterNames.Kid, out identifier) || identifier == null)
                        {
                            // When the token doesn't contain a "kid" parameter in the header, automatically
                            // add one using the identifier specified in the signing credentials.
                            identifier = notification.SigningCredentials.Kid;

                            if (identifier == null)
                            {
                                // When no key identifier has been explicitly added by the developer, a "kid" is automatically
                                // inferred from the hexadecimal representation of the certificate thumbprint (SHA-1).
                                if (x509SecurityKey != null)
                                {
                                    identifier = x509SecurityKey.Certificate.Thumbprint;
                                }

                                // When no key identifier has been explicitly added by the developer, a "kid"
                                // is automatically inferred from the modulus if the signing key is a RSA key.
                                var rsaSecurityKey = notification.SigningCredentials.Key as RsaSecurityKey;
                                if (rsaSecurityKey != null)
                                {
                                    // Only use the 40 first chars to match the identifier used by the JWKS endpoint.
                                    identifier = Base64UrlEncoder.Encode(rsaSecurityKey.Parameters.Modulus)
                                                 .Substring(0, 40)
                                                 .ToUpperInvariant();
                                }
                            }

                            token.Header[JwtHeaderParameterNames.Kid] = identifier;
                        }
                    }

                    return(Task.FromResult(notification.SecurityTokenHandler.WriteToken(token)));
                };

                await Options.Provider.SerializeIdentityToken(notification);

                // Treat a non-null identity token like an implicit HandleResponse call.
                if (notification.HandledResponse || !string.IsNullOrEmpty(notification.IdentityToken))
                {
                    return(notification.IdentityToken);
                }

                else if (notification.Skipped)
                {
                    return(null);
                }

                // Allow the application to change the authentication
                // ticket from the SerializeIdentityTokenAsync event.
                ticket = notification.AuthenticationTicket;
                ticket.Properties.CopyTo(properties);

                return(await notification.SerializeTicketAsync());
            }

            catch (Exception exception) {
                Logger.LogWarning("An exception occured when serializing an identity token.", exception);

                return(null);
            }
        }
        private async Task <string> SerializeIdentityTokenAsync(
            ClaimsPrincipal principal, AuthenticationProperties properties,
            OpenIdConnectMessage request, OpenIdConnectMessage response)
        {
            // properties.IssuedUtc and properties.ExpiresUtc
            // should always be preferred when explicitly set.
            if (properties.IssuedUtc == null)
            {
                properties.IssuedUtc = Options.SystemClock.UtcNow;
            }

            if (properties.ExpiresUtc == null)
            {
                properties.ExpiresUtc = properties.IssuedUtc + Options.IdentityTokenLifetime;
            }

            // Replace the principal by a new one containing only the filtered claims.
            // Actors identities are also filtered (delegation scenarios).
            principal = principal.Clone(claim => {
                // Never exclude ClaimTypes.NameIdentifier.
                if (string.Equals(claim.Type, ClaimTypes.NameIdentifier, StringComparison.OrdinalIgnoreCase))
                {
                    return(true);
                }

                // Claims whose destination is not explicitly referenced or doesn't
                // contain "id_token" are not included in the identity token.
                return(claim.HasDestination(OpenIdConnectConstants.Destinations.IdentityToken));
            });

            var identity = (ClaimsIdentity)principal.Identity;

            // Create a new ticket containing the updated properties and the filtered principal.
            var ticket = new AuthenticationTicket(principal, properties, Options.AuthenticationScheme);

            ticket.SetUsage(OpenIdConnectConstants.Usages.IdToken);

            // By default, add the client_id to the list of the
            // presenters allowed to use the identity token.
            if (!string.IsNullOrEmpty(request.ClientId))
            {
                ticket.SetAudiences(request.ClientId);
                ticket.SetPresenters(request.ClientId);
            }

            var notification = new SerializeIdentityTokenContext(Context, Options, request, response, ticket)
            {
                Issuer = Context.GetIssuer(Options),
                SecurityTokenHandler = Options.IdentityTokenHandler,
                SigningCredentials   = Options.SigningCredentials.FirstOrDefault()
            };

            await Options.Provider.SerializeIdentityToken(notification);

            if (!string.IsNullOrEmpty(notification.IdentityToken))
            {
                return(notification.IdentityToken);
            }

            if (notification.SecurityTokenHandler == null)
            {
                return(null);
            }

            if (!identity.HasClaim(claim => claim.Type == JwtRegisteredClaimNames.Sub) &&
                !identity.HasClaim(claim => claim.Type == ClaimTypes.NameIdentifier))
            {
                Logger.LogError("A unique identifier cannot be found to generate a 'sub' claim: " +
                                "make sure to add a 'ClaimTypes.NameIdentifier' claim.");

                return(null);
            }

            // Extract the main identity from the principal.
            identity = (ClaimsIdentity)ticket.Principal.Identity;

            // Store the unique subject identifier as a claim.
            if (!identity.HasClaim(claim => claim.Type == JwtRegisteredClaimNames.Sub))
            {
                identity.AddClaim(JwtRegisteredClaimNames.Sub, identity.GetClaim(ClaimTypes.NameIdentifier));
            }

            // Remove the ClaimTypes.NameIdentifier claims to avoid getting duplicate claims.
            // Note: the "sub" claim is automatically mapped by JwtSecurityTokenHandler
            // to ClaimTypes.NameIdentifier when validating a JWT token.
            // Note: make sure to call ToArray() to avoid an InvalidOperationException
            // on old versions of Mono, where FindAll() is implemented using an iterator.
            foreach (var claim in identity.FindAll(ClaimTypes.NameIdentifier).ToArray())
            {
                identity.RemoveClaim(claim);
            }

            // Store the "usage" property as a claim.
            identity.AddClaim(OpenIdConnectConstants.Claims.Usage, ticket.GetUsage());

            // If the ticket is marked as confidential, add a new
            // "confidential" claim in the security token.
            if (ticket.IsConfidential())
            {
                identity.AddClaim(new Claim(OpenIdConnectConstants.Claims.Confidential, "true", ClaimValueTypes.Boolean));
            }

            // Store the audiences as claims.
            foreach (var audience in ticket.GetAudiences())
            {
                identity.AddClaim(JwtRegisteredClaimNames.Aud, audience);
            }

            // If a nonce was present in the authorization request, it MUST
            // be included in the id_token generated by the token endpoint.
            // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
            var nonce = request.Nonce;

            if (request.IsAuthorizationCodeGrantType())
            {
                // Restore the nonce stored in the authentication
                // ticket extracted from the authorization code.
                nonce = ticket.GetNonce();
            }

            if (!string.IsNullOrEmpty(nonce))
            {
                identity.AddClaim(JwtRegisteredClaimNames.Nonce, nonce);
            }

            if (!string.IsNullOrEmpty(response.Code))
            {
                using (var algorithm = OpenIdConnectServerHelpers.GetHashAlgorithm(notification.SigningCredentials.Algorithm)) {
                    // Create the c_hash using the authorization code returned by SerializeAuthorizationCodeAsync.
                    var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.Code));

                    // Note: only the left-most half of the hash of the octets is used.
                    // See http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken
                    identity.AddClaim(JwtRegisteredClaimNames.CHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                }
            }

            if (!string.IsNullOrEmpty(response.AccessToken))
            {
                using (var algorithm = OpenIdConnectServerHelpers.GetHashAlgorithm(notification.SigningCredentials.Algorithm)) {
                    // Create the at_hash using the access token returned by SerializeAccessTokenAsync.
                    var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.AccessToken));

                    // Note: only the left-most half of the hash of the octets is used.
                    // See http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
                    identity.AddClaim(JwtRegisteredClaimNames.AtHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                }
            }

            // Extract the presenters from the authentication ticket.
            var presenters = ticket.GetPresenters().ToArray();

            switch (presenters.Length)
            {
            case 0: break;

            case 1:
                identity.AddClaim(JwtRegisteredClaimNames.Azp, presenters[0]);
                break;

            default:
                Logger.LogWarning("Multiple presenters have been associated with the identity token " +
                                  "but the JWT format only accepts single values.");

                // Only add the first authorized party.
                identity.AddClaim(JwtRegisteredClaimNames.Azp, presenters[0]);
                break;
            }

            var token = notification.SecurityTokenHandler.CreateJwtSecurityToken(
                subject: identity,
                issuer: notification.Issuer,
                signingCredentials: notification.SigningCredentials,
                issuedAt: ticket.Properties.IssuedUtc.Value.UtcDateTime,
                notBefore: ticket.Properties.IssuedUtc.Value.UtcDateTime,
                expires: ticket.Properties.ExpiresUtc.Value.UtcDateTime);

            var x509SecurityKey = notification.SigningCredentials?.Key as X509SecurityKey;

            if (x509SecurityKey != null)
            {
                // Note: unlike "kid", "x5t" is not automatically added by JwtHeader's constructor in IdentityModel for .NET Core.
                // Though not required by the specifications, this property is needed for IdentityModel for Katana to work correctly.
                // See https://github.com/aspnet-contrib/AspNet.Security.OpenIdConnect.Server/issues/132
                // and https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/issues/181.
                token.Header[JwtHeaderParameterNames.X5t] = Base64UrlEncoder.Encode(x509SecurityKey.Certificate.GetCertHash());
            }

            return(notification.SecurityTokenHandler.WriteToken(token));
        }
Ejemplo n.º 4
0
 /// <summary>
 /// Called to create a new identity token. An application may use this context
 /// to replace the authentication ticket before it is serialized or to use its own token format
 /// and skip the default logic using <see cref="BaseControlContext.HandleResponse"/>.
 /// </summary>
 /// <param name="context">The context of the event carries information in and results out.</param>
 /// <returns>Task to enable asynchronous execution</returns>
 public virtual Task SerializeIdentityToken(SerializeIdentityTokenContext context) => OnSerializeIdentityToken(context);
 /// <summary>
 /// Called to create a new identity token. An application may use this context
 /// to replace the authentication ticket before it is serialized or to use its own token format
 /// and skip the default logic using <see cref="BaseContext{OpenIdConnectServerOptions}.HandleResponse"/>.
 /// </summary>
 /// <param name="context">The context of the event carries information in and results out.</param>
 /// <returns>Task to enable asynchronous execution</returns>
 public virtual Task SerializeIdentityToken(SerializeIdentityTokenContext context) => OnSerializeIdentityToken(context);
Ejemplo n.º 6
0
        private async Task <string> SerializeIdentityTokenAsync(
            ClaimsPrincipal principal, AuthenticationProperties properties,
            OpenIdConnectRequest request, OpenIdConnectResponse response)
        {
            // properties.IssuedUtc and properties.ExpiresUtc
            // should always be preferred when explicitly set.
            if (properties.IssuedUtc == null)
            {
                properties.IssuedUtc = Options.SystemClock.UtcNow;
            }

            if (properties.ExpiresUtc == null)
            {
                properties.ExpiresUtc = properties.IssuedUtc + Options.IdentityTokenLifetime;
            }

            // Replace the principal by a new one containing only the filtered claims.
            // Actors identities are also filtered (delegation scenarios).
            principal = principal.Clone(claim => {
                // Never exclude ClaimTypes.NameIdentifier.
                if (string.Equals(claim.Type, ClaimTypes.NameIdentifier, StringComparison.OrdinalIgnoreCase))
                {
                    return(true);
                }

                // Claims whose destination is not explicitly referenced or doesn't
                // contain "id_token" are not included in the identity token.
                return(claim.HasDestination(OpenIdConnectConstants.Destinations.IdentityToken));
            });

            var identity = (ClaimsIdentity)principal.Identity;

            // Create a new ticket containing the updated properties and the filtered principal.
            var ticket = new AuthenticationTicket(principal, properties, Options.AuthenticationScheme);

            ticket.SetUsage(OpenIdConnectConstants.Usages.IdentityToken);

            // Associate a random identifier with the identity token.
            ticket.SetTicketId(Guid.NewGuid().ToString());

            // By default, add the client_id to the list of the
            // presenters allowed to use the identity token.
            if (!string.IsNullOrEmpty(request.ClientId))
            {
                ticket.SetAudiences(request.ClientId);
                ticket.SetPresenters(request.ClientId);
            }

            var notification = new SerializeIdentityTokenContext(Context, Options, request, response, ticket)
            {
                Issuer = Context.GetIssuer(Options),
                SecurityTokenHandler = Options.IdentityTokenHandler,
                SigningCredentials   = Options.SigningCredentials.FirstOrDefault()
            };

            await Options.Provider.SerializeIdentityToken(notification);

            if (notification.HandledResponse || !string.IsNullOrEmpty(notification.IdentityToken))
            {
                return(notification.IdentityToken);
            }

            else if (notification.Skipped)
            {
                return(null);
            }

            if (!ReferenceEquals(ticket, notification.Ticket))
            {
                throw new InvalidOperationException("The authentication ticket cannot be replaced.");
            }

            if (notification.SecurityTokenHandler == null)
            {
                return(null);
            }

            if (!identity.HasClaim(claim => claim.Type == OpenIdConnectConstants.Claims.Subject) &&
                !identity.HasClaim(claim => claim.Type == ClaimTypes.NameIdentifier))
            {
                throw new InvalidOperationException("A unique identifier cannot be found to generate a 'sub' claim: " +
                                                    "make sure to add a 'ClaimTypes.NameIdentifier' claim.");
            }

            if (notification.SigningCredentials == null)
            {
                throw new InvalidOperationException("A signing key must be provided.");
            }

            // Extract the main identity from the principal.
            identity = (ClaimsIdentity)ticket.Principal.Identity;

            // Store the unique subject identifier as a claim.
            if (!identity.HasClaim(claim => claim.Type == OpenIdConnectConstants.Claims.Subject))
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.Subject, identity.GetClaim(ClaimTypes.NameIdentifier));
            }

            // Remove the ClaimTypes.NameIdentifier claims to avoid getting duplicate claims.
            // Note: the "sub" claim is automatically mapped by JwtSecurityTokenHandler
            // to ClaimTypes.NameIdentifier when validating a JWT token.
            // Note: make sure to call ToArray() to avoid an InvalidOperationException
            // on old versions of Mono, where FindAll() is implemented using an iterator.
            foreach (var claim in identity.FindAll(ClaimTypes.NameIdentifier).ToArray())
            {
                identity.RemoveClaim(claim);
            }

            // Store the "unique_id" property as a claim.
            identity.AddClaim(OpenIdConnectConstants.Claims.JwtId, ticket.GetTicketId());

            // Store the "usage" property as a claim.
            identity.AddClaim(OpenIdConnectConstants.Claims.Usage, ticket.GetUsage());

            // Store the "confidentiality_level" property as a claim.
            var confidentiality = ticket.GetProperty(OpenIdConnectConstants.Properties.ConfidentialityLevel);

            if (!string.IsNullOrEmpty(confidentiality))
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.ConfidentialityLevel, confidentiality);
            }

            // Store the audiences as claims.
            foreach (var audience in notification.Audiences)
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.Audience, audience);
            }

            // If a nonce was present in the authorization request, it MUST
            // be included in the id_token generated by the token endpoint.
            // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
            var nonce = request.Nonce;

            if (request.IsAuthorizationCodeGrantType())
            {
                // Restore the nonce stored in the authentication
                // ticket extracted from the authorization code.
                nonce = ticket.GetProperty(OpenIdConnectConstants.Properties.Nonce);
            }

            if (!string.IsNullOrEmpty(nonce))
            {
                identity.AddClaim(OpenIdConnectConstants.Claims.Nonce, nonce);
            }

            using (var algorithm = OpenIdConnectServerHelpers.GetHashAlgorithm(notification.SigningCredentials.Algorithm)) {
                // Create an authorization code hash if necessary.
                if (!string.IsNullOrEmpty(response.Code))
                {
                    var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.Code));

                    // Note: only the left-most half of the hash of the octets is used.
                    // See http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken
                    identity.AddClaim(OpenIdConnectConstants.Claims.CodeHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                }

                // Create an access token hash if necessary.
                if (!string.IsNullOrEmpty(response.AccessToken))
                {
                    var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.AccessToken));

                    // Note: only the left-most half of the hash of the octets is used.
                    // See http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
                    identity.AddClaim(OpenIdConnectConstants.Claims.AccessTokenHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2));
                }
            }

            // Extract the presenters from the authentication ticket.
            var presenters = notification.Presenters.ToArray();

            switch (presenters.Length)
            {
            case 0: break;

            case 1:
                identity.AddClaim(OpenIdConnectConstants.Claims.AuthorizedParty, presenters[0]);
                break;

            default:
                Logger.LogWarning("Multiple presenters have been associated with the identity token " +
                                  "but the JWT format only accepts single values.");

                // Only add the first authorized party.
                identity.AddClaim(OpenIdConnectConstants.Claims.AuthorizedParty, presenters[0]);
                break;
            }

            var token = notification.SecurityTokenHandler.CreateToken(new SecurityTokenDescriptor {
                Subject            = identity,
                Issuer             = notification.Issuer,
                SigningCredentials = notification.SigningCredentials,
                IssuedAt           = notification.Ticket.Properties.IssuedUtc?.UtcDateTime,
                NotBefore          = notification.Ticket.Properties.IssuedUtc?.UtcDateTime,
                Expires            = notification.Ticket.Properties.ExpiresUtc?.UtcDateTime
            });

            return(notification.SecurityTokenHandler.WriteToken(token));
        }