Applications wanting to communicate securely to one another may establish a secure connection. Each application opens a socket and attempts to establish an SSL connection. After an SSL connection is established, the applications may now use the socket to exchange data securely. The default (blocking) mode of a socket requires an application attempting to read or write to the socket to block until all expected data is received. This blocking may not be desirable since no other processing may occur while the application is waiting for a read or write to complete. One solution to this problem is the use of non-blocking sockets.

When a socket is set up as non-blocking, reads and writes to the socket do not cause the application to block and wait. Instead the read or write function will read/write only the data currently available (if any). If the entire read/write is not completed, a status indicator is returned. The application might try read/write again later.