Data communications
First Claim
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1. A method of operating a data communications system comprising:
- a) at a remote data source, outputting a plurality of application data units (ADUs);
b) encrypting the ADUs;
c) communicating the ADUs to a customer terminal;
d) in the locality of the customer terminal, decrypting the ADUs;
e) storing a record of the ADUs decrypted in step (d); and
f) subsequently generating a receipt for ADUs received at the customer terminal by reading record data stored in step (e).
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Abstract
In a data communications system a remote data source outputs data as a series of application data units (ADUs). Each ADU is individually encrypted with a different key. The keys are transmitted (for example using Internet multicasting) via a communications network to one or more customer terminals. At the terminals a sequence of keys is generated for use in decrypting the ADUs. A record is kept of the keys generated, and this record may subsequently be used to generate a receipt for the data received by the customer. The keys may be generated, and the record stored within a secure module such as a smartcard.
66 Citations
36 Claims
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1. A method of operating a data communications system comprising:
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a) at a remote data source, outputting a plurality of application data units (ADUs); b) encrypting the ADUs; c) communicating the ADUs to a customer terminal; d) in the locality of the customer terminal, decrypting the ADUs; e) storing a record of the ADUs decrypted in step (d); and f) subsequently generating a receipt for ADUs received at the customer terminal by reading record data stored in step (e). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 17, 18, 20, 24, 25, 26, 27)
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12. A data communications system comprising
a) a remote data source arranged to output a plurality of ADUs; -
b) encryption means for encrypting the plurality of ADUs; c) a communications network connected to the encryption means; d) a customer terminal connected to the communications network and arranged to receive encrypted ADUs via the communications network; e) decryption means located in the locality of the customer terminal and arranged to decrypt the ADUs received at the customer terminal from the communications network; f) a store at the customer terminal for storing a record of ADUs decrypted by the decryption means; g) means for reading record data from the store and generating thereby a receipt for ADUs received and decrypted by the customer terminal. - View Dependent Claims (13, 14, 15, 16, 19)
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21. A method of operating a data communications system comprising:
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a) at a remote data source, outputting a plurality of ADUs b) encrypting different ones of the plurality of ADUs using different respective keys; c) communicating ADUs to a customer terminal; d) in the locality of the customer terminal, generating a plurality of different keys for decrypting different respective ADUs received at the customer terminal; e) storing a readable record of the keys generated in step (d). - View Dependent Claims (23)
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22. A data communications system comprising
a) a remote data source arranged to output a plurality of ADUs; -
b) encryption means for encrypting the plurality of ADUs with different respective keys; c) a communications network connected to the encryption means; d) a customer terminal connected to the communications network and arranged to receive encrypted ADUs via the communications network; e) a key generator programmed to generate a sequence of keys for use in decrypting ADUs; f) decryption means connected to the key generator and arranged to decrypt the ADUs received at the customer terminal from the communications network; and g) a store for storing a readable record of keys generated by the key generator means.
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28. A method of operating a data communications system comprising:
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a) at a remote data source, outputting a plurality of application data units (ADUs); b) encrypting the ADUs; c) communicating the ADUs to a plurality of customer terminals; d) in the locality of each customer terminal, decrypting the ADUs; and e) inducing a different characteristic variation in the value of the ADU'"'"'s at different respective terminals. - View Dependent Claims (29, 30, 31, 32, 33, 35, 36)
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34. A method of operating a data communications system comprising:
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a) at a plurality of remote data sources, outputting a plurality of application data units (ADUs); b) encrypting the ADUs from different remote data sources with different respective keys derived from a common seed value; c) communicating the ADUs to a plurality of customer terminals; d) in the locality of each customer terminal, decrypting the ADU'"'"'s.
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Specification