Return the message digest selected when establishing the secure
connection with the server.
The SecureHash property returns an integer value which
identifies the message digest algorithm that was selected when a
secure connection is established. This property may return one of the
||No message digest algorithm has been selected. This is not a
secure connection with the server.
||The MD5 algorithm was selected. This algorithm takes a
message of arbitrary length and produces a 128-bit message
||The SHA algorithm was selected. This algorithm produces a
160-bit message digest.
If a secure connection has not been established, this property
will return a value of zero.