Authentication Level

Authentication is the process by which client and server use credentials to verify each another's identity and by which they verify and encrypt data that passes between them.

The authentication level setting indicates what degree of authentication is required for communication with an application (when it makes or receives calls). Higher authentication levels provide greater security and data integrity, although usually with some performance degradation.

Using the Component Services administrative tool, you can change the machine-wide setting for the authentication level. This machine-wide setting is used when a COM application doesn't specify an authentication level programmatically. The default setting for machine-wide authentication level is Connect.

For step-by-step instructions on setting levels, see Setting the Machine-Wide Authentication Level.

The levels, from lowest to highest security, are described in the following table.

Level	Description
None	No authentication occurs.
Connect	Authenticates credentials only when the connection is made.
Call	Authenticates credentials at the beginning of every call.
Packet	Authenticates credentials and verifies that all call data is received.
Packet Integrity	Authenticates credentials and verifies that no call data has been modified in transit.
Packet Privacy	Authenticates credentials and encrypts the packet, including the data and the sender's identity and signature.