What is the difference between Integrated Security = True and Integrated Security = SSPI?

To connect to the database server is recommended to use Windows Authentication, commonly known as integrated security. To specify the Windows authentication, you can use any of the following two key-value pairs with the data provider. NET Framework for SQL Server:

Integrated Security = true;
Integrated Security = SSPI;

However, only the second works with the data provider .NET Framework OleDb. If you set Integrated Security = true for ConnectionString an exception is thrown.