Koninklijke Ptt Nederland N.v.

Jean Paul Boly

Martin Klaas De Lange

Gerrit Roelofsen

Albertus Feiken

Maurice Matthias Feijen

Gerrit J Van Loo

Device for processing data packets

A device for encrypting or decrypting data packets. The device includes two cryptographic elements. The first cryptographic element generates processing data, based on a first starting value, for use in cryptographically processing the data packet. The second cryptographic element is arranged to generate the first starting value based on a second starting value. The second starting value is based on a previously cryptographically processed data packet.

Device for cryptographically processing data packets and method of

In a system for de-/encoding data using (de)coding devices at either end of a transmission channel, the data sometimes comprise additional synchronisation information which is used to reduce the effect of faults in the transmission channel. If this synchronisation information is not already present, it is impossible in certain cases to add such information. The invention provides a system which, regardless of the presence of additional synchronisation information, is able to reduce the effect of faults. For this purpose, each (de)coding device is provided with means for comparing sequences of encoded data with at least one predetermined code word and for setting the associated coding device to a reset state in the event of equality. Because the predetermined code word repeats statistically in the encoded data, a fault adversely affects the decoding for not more than one time interval.

System for encoding data presented with a first coding device and for

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Zoeterwoude, Netherlands

Jean Paul Boly