# <authentication> of <serviceCertificate> Element

Specifies the settings used by the client proxy to authenticate service certificates that are obtained using SSL/TLS negotiation.

## Syntax

<authentication customCertificateValidatorType="String"
certificateValidationMode="None/PeerTrust/ChainTrust/PeerOrChainTrust/Custom"
revocationMode="NoCheck/Online/Offline"
trustedStoreLocation="LocalMachine/CurrentUser" />


## Attributes and Elements

The following sections describe attributes, child elements, and parent elements

### Attributes

Attribute Description
customCertificateValidatorType String. A type and assembly used to validate a custom type.
certificateValidationMode Specifies one of three modes used to validate credentials. If set to Custom, then a customCertificateValidator must also be supplied. The default is ChainTrust.
revocationMode One of the modes used to check for a revoked certificate lists (CRL). The default is Online.
trustedStoreLocation One of the two system store locations: LocalMachine or CurrentUser. This value is used when a service certificate is negotiated to the client. Validation is performed against the Trusted People store in the specified store location. The default is CurrentUser.

## customCertificateValidator Attribute

Value Description
String Specifies the type name and assembly and other data used to find the type.

## certificateValidationMode Attribute

Value Description
Enumeration One of the following values: None, PeerTrust, ChainTrust, PeerOrChainTrust, Custom.

## revocationMode Attribute

Value Description
Enumeration One of the following values: NoCheck, Online, Offline.

## trustedStoreLocation Attribute

Value Description
Enumeration One of the following values: LocalMachine or CurrentUser. The default is CurrentUser. If the client application is running under a system account, then the certificate is typically under LocalMachine. If the client application is running under a user account, then the certificate is typically in CurrentUser.

None.

### Parent Elements

Element Description
<serviceCertificate> Specifies a certificate to use when authenticating a service to the client.

## Remarks

The certificateValidationMode attribute of this configuration element specifies the level of trust used to authenticate certificates. By default, the level is set to ChainTrust, which specifies that each certificate must be found in a hierarchy of certificates ending in a trusted certification authority at the top of the chain. This is the most secure mode. You can also set the value to PeerOrChainTrust, which specifies that self-issued certificates (peer trust) are accepted as well as certificates that are in a trusted chain. This value is used when developing and debugging clients and services because self-issued certificates need not be purchased from a trusted authority. When deploying a client, use the ChainTrust value instead. You can also set the value to Custom or None. To use the Custom value, you must also set the customCertificateValidator attribute to an assembly and type used to validate the certificate. To create your own custom validator, you must inherit from the abstract X509CertificateValidator class. For more information, see How to: Create a Service that Employs a Custom Certificate Validator.

The revocationMode attribute specifies how certificates are checked for revocation. The default is online which indicates that certificates will be checked automatically for revocation. For more information, see Working with Certificates.

## Example

The following example does two tasks. It first specifies a service certificate for the client to use when communicating with endpoints whose domain name is www.contoso.com over the HTTP protocol. Second, it specifies the revocation mode and store location used during authentication.

<serviceCertificate>
<defaultCertificate findValue="www.contoso.com"
storeLocation="LocalMachine"
storeName="TrustedPeople"
x509FindType="FindByIssuerDistinguishedName" />
<scopedCertificates>