SILC SFTP Interface is the implementation of the Secure File Transfer
    Protocol.  The interface defines the SFTP client and the SFTP server.
    The SFTP is the mandatory file transfer protocol in the SILC protocol.
    The SFTP server implementation is filesystem independent and generic
    interface is defined to represent filesystem access.

    The SilcSFTP context is the actual SFTP client or SFTP server, and
    each SFTP session (associated to a socket connection) must create
    own SFTP context.