| 摘要 |
The deciphering of fragmented enciphered IP packets is perfomed without requiring reassembly of the fragments fragmented packets. When a first frame is deciphered a characteristic poly-tuple is saved against the state of the cipher, particularly an output vector. When the next frame comes in, the cipher would continue on from that previously saved state after a look-up of the poly-tuple. Each frame would then be sent on, deciphered, but still representing a fragment of the original packet. The poly-tuple employed for the look-up includes the identity and protocol fields from the IP header and at least one of the source IP address and the destination IP address. The deciphering process may commence with the combination of input data with an initialising vector and proceed by combining input data with a vector fed back from the output of the deciphering engine. The saved cipher state is employed as the initialising vector for the next frame.
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