RPC_C_AUTHN_LEVEL_DEFAULT

Uses the default authentication level for the specified authentication service.

RPC_C_AUTHN_LEVEL_NONE

Performs no authentication.

RPC_C_AUTHN_LEVEL_CONNECT

Authenticates only when the client establishes a relationship with a server.

RPC_C_AUTHN_LEVEL_CALL

Authenticates only at the beginning of each remote procedure call when the server receives the request. Does not apply to remote procedure calls made using the connection-based protocol sequences (those that start with the prefix "ncacn"). If the protocol sequence in a binding handle is a connection-based protocol sequence and you specify this level, this routine instead uses the RPC_C_AUTHN_LEVEL_PKT constant.

RPC_C_AUTHN_LEVEL_PKT

Authenticates only that all data received is from the expected client. Does not validate the data itself.

RPC_C_AUTHN_LEVEL_PKT_INTEGRITY

Authenticates and verifies that none of the data transferred between client and server has been modified.

RPC_C_AUTHN_LEVEL_PKT_PRIVACY

Includes all previous levels, and ensures clear text data can only be seen by the sender and the receiver. In the local case, this involves using a secure channel. In the remote case, this involves encrypting the argument value of each remote procedure call.