Patent ID: 8645689

Claim:
A method in a first computer system for secure data transfer, comprising: generating a first list of labels of one or more content structures, each label in the first list corresponding to a content structure that includes a hierarchy of files; engaging in a first data transfer session with a second computer system, said engaging in a first data transfer session comprising transmitting the first list to the second computer system a first time, and transmitting authentication information, at least one file included in the one or more content structures, and one or more file identifiers for one or more files included in the one or more content structures that are excluded from the first data transfer session to the second computer system a first time; receiving a second list from the second computer system that lists one or more requested files identified by the transmitted one or more file identifiers; and engaging in a second data transfer session with the second computer system, said engaging in a second data transfer session comprising transmitting the first list to the second computer system a second time, transmitting authentication information and the previously transmitted at least one file to the second computer system a second time, the previously transmitted at least one file being unmodified since being transmitted the first time, and transmitting the one or more requested files to the second computer system for a first time.