> For the complete documentation index, see [llms.txt](https://docs.lithnet.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lithnet.io/ams/v1.0/configuration/setting_up_authentication/enabling-altsecurityidentities.md). # Setting up smart card authentication The default implementation of smart card/certificate support requires that the certificate contain a subject alternative name (SAN) containing the user's UPN in order for them to successfully log on. You can also enable support for Active Directory altSecurityIdentities, to support certificates without a UPN. The caveat with this implementation is that this only works in the forest that the AMS service is located within. As web-based certificate authentication happens at the TLS level, AMS is unable to prompt for a username or domain hint. Therefore, AMS can only search the local global catalog for the altSecurityIdentity values. In line with the [Microsoft implementation](https://docs.microsoft.com/en-us/windows/security/identity-protection/smart-cards/smart-card-certificate-requirements-and-enumeration) for altSecurityIdentities, AMS searches the directory for a user match in the following order ``` X509: X509:* X509: X509: X509: X509:* ``` > (\*) Use of these altSecurityIdentity types requires that certificate issuer validation against the NT Auth store is enabled ### Enabling altSecurityIdentities Support First, ensure you save and close any instances of the Access Manager Configuration Tool. Then navigate to the AMS config file, usually located at `C:\Program Files\Lithnet\Access Manager Service\config\appsettings.json` Locate the `ClientCert` element, and set the `IdentityResolutionMode` value to one of the following values | Value | Description | | ------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `Default` | Default behavior (equivalent to `UpnSan`) | | `UpnSan` | Find the user using the UPN located in the certificate's subject alternative names. If the UPN is not present, or no match can be found in the directory, the user login is denied | | `AltSecurityIdentities` | Find the user using the altSecurityIdentities attribute. If no match can be found, the user login is denied | | `UpnSan, AltSecurityIdentities` | First, attempt to find the user using the UPN located in the certificate's subject alternative names. If the UPN is not present, or no match can be found in the directory, try to find the user using the altSecurityIdentities attribute. If no match can be found, the user login is denied. Note that the order of these values does not matter. The UPN check will always be performed first. | Example ```json "ClientCert": { "RequiredEkus": [], "ValidationMethod": "NtAuthStore", "RequireSmartCardLogonEku": true, "TrustedIssuers": [], "IdentityResolutionMode": "UpnSan, AltSecurityIdentities" } ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.lithnet.io/ams/v1.0/configuration/setting_up_authentication/enabling-altsecurityidentities.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.