Cryptographic data communication apparatus

Data communication apparatus, comprising:

• packet processing circuitry configured to:
• receive data including a first data chunk from a memory responsively to a data transfer request;
• find that the first data chunk includes a first partial block;
• request a first additional data chunk from the memory;
• cryptographically process the received data in units of data blocks using a block cipher including cryptographically processing the first partial block and the first additional data chunk together as a whole block using the block cipher yielding a first cryptographically processed data block;
• add cryptographically processed data blocks to a sequence of data packets, wherein non-aligned cryptographically processed data blocks of the cryptographically processed data blocks have block boundaries that are not aligned with packet payload boundaries;
• and
• divide each of the non-aligned cryptographically processed data blocks into two respective segments, which are contained in successive packets in the sequence;
• and
• a network interface which comprises one or more ports for connection to a packet data network and is configured to send the sequence of data packets to a remote device over the packet data network via the one or more ports.