Establishing a transfer mode between devices for large bulk records over a TLS protocol by fragmenting an encrypted bulk record into a set of pre-defined block sizes for convenient transfer. The pre-defined block sizes are specifically sized to indicate a beginning and an end of the transfer of the associated blocks making up the large bulk record. A middle box is unaware of the association between the blocks and permits transfer according to the maximum transmission unit of the transport layer security (TLS) protocol. The fragmented bulk record is reconstructed and decrypted for use after the transfer.