TLS works over transport layer, packet fragmentation/defragmentation is controlled by transport layer, when we attempt to send a file over TLS/SSL ,is the MAC is generated over entire-file-content or a portion of file OR that would vary on underlying application layer protocol (HTTPS/FTPS)?
1 Answer
Data are sent within TLS in records and the MAC is computed over the contents of the record, see http://en.wikipedia.org/wiki/Transport_Layer_Security#TLS_record. The size of the record is independent of any packet sizes of the underlying transport layer, that is a packet can contain multiple records or a record can also span multiple packets. The record size is also independent of any file sizes since there is no idea of a file anyway with TLS, only of data.