<!-- loio58a75377cc154f44bb81c0376d330901 -->
# Authentication Options \(Outbound\)
For outbound communication through HTTPS \(when the tenant sends a message to a receiver\), the following authentication options are supported.
- **Basic authentication**
The calling entity \(tenant\) is authenticated based on credentials \(user name and password\)
- **Client-certificate authentication**
The calling entity \(tenant\) is authenticated based on a certificate.
- OAuth
**Related Information**
[Basic Authentication](basic-authentication-a5d77b1.md "Basic authentication allows a the tenant to authenticate itself against the receiver through credentials (user name and password).")
[Client Certificate Authentication \(Outbound\)](client-certificate-authentication-outbound-c4e4a15.md "")
[OAuth 2.0](oauth-2-0-3823134.md#loio382313443b8d4453b0fd536b82b9e15d "OAuth 2.0 allows a user to grant a client access to a protected resource (hosted by a resource server). The user typically restricts the access of the client and doesn't allow full access.")