Priority-based ordering of cryptographic processing in wireless communication apparatus

1. A method of processing data streams received or to be transmitted by a wireless communication apparatus comprising a crypto-processor, each data stream at least partly requiring a cryptographic processing operation, comprising:

assigning a data type and a cryptographic processing type to each data stream, wherein cryptographic processing types include at least data streams having encrypted packets and requiring cryptographic pre-processing followed by cryptographic post-processing and data streams requiring synchronous cryptographic processing;

processing at least some of the data streams within the crypto-processor according to an order of priority defined from the assigned data types and the cryptographic processing types; and

wherein the cryptographic pre-processing includes a pre-calculation of an encrypting sequence that is performed based on a reception quality of the data streams and an indication associated with a change-of-cell.

2. The method of claim 1 wherein a data type comprises a data stream being a control stream or a user stream and wherein the control streams are processed as a higher priority than the user streams.

3. The method of claim 2 wherein a cryptographic processing type comprises a data stream requiring pre-processing followed by post-processing, and wherein the data streams for which the pre-processing has already been carried out are processed as a higher priority than the data streams for which the pre-processing has yet to be carried out.

4. The method of claim 3 wherein the pre-processing is performed in the crypto-processor and the post-processing is performed outside the crypto-processor.

5. The method of claim 3 wherein:

the data stream comprises a sequence of encrypted packets;

the pre-processing comprises, for each packet, the pre-calculation of the encrypting sequence;

the post-processing comprises a decryption of a packet with the corresponding encrypting sequence; and

wherein the pre-calculation of the encrypting sequence is performed if the reception quality is greater than a threshold and if no change-of-cell indication is received.

6. The method of claim 3 wherein a cryptographic processing type comprises a data stream requiring synchronous processing, and wherein, after having processed as a priority the data streams for which a pre-processing has already been carried out, the data streams requiring a synchronous processing are processed as a priority.

7. The method of claim 1 , wherein the data type is one of a control stream and a user stream.

8. A wireless communication apparatus, comprising:

a transceiver operative to receive and transmit data streams, each at least partly requiring a cryptographic processing operation; and

a cryptographic module comprising:

a crypto-processor;

a cryptographic management circuit operative to deliver at least some of the data streams to the crypto-processor according to an order of priority defined from a data type and a cryptographic processing type assigned to each data stream, wherein cryptographic processing types include at least data streams having encrypted packets and requiring cryptographic pre-processing followed by cryptographic post-processing and data streams requiring synchronous cryptographic processing; and

wherein the cryptographic pre-processing includes a pre-calculation of an encrypting sequence that is performed based on a reception quality of the data streams and an indication associated with a change-of-cell.

9. The apparatus of claim 8 wherein a data type comprises a data stream being a control stream or a user stream, and wherein the cryptographic management circuit is further operative to deliver to the crypto-processor the control streams as a higher priority than the user streams.

10. The apparatus of claim 9 wherein a cryptographic processing type comprises a data stream requiring pre-processing followed by a post-processing and wherein the cryptographic management circuit is further operative to deliver to the cryptographic module the data streams for which the pre-processing has already been carried out, as a higher priority than the data streams for which the pre-processing has yet to be carried out.

11. The apparatus of claim 10 further comprising a processing block external to the crypto-processor, and wherein the crypto-processor is operative to perform the pre-processing and the external processing block is operative to perform the post-processing.

12. The apparatus of claim 10 wherein a cryptographic processing type comprises a data stream requiring synchronous processing, and wherein the cryptographic management circuit is further operative, after having delivered to the cryptographic module the data streams for which the pre-processing has already been performed, to deliver to the cryptographic module the data streams requiring synchronous processing, as a priority.

13. The apparatus of claim 8 wherein:

the transceiver is operative to receive a sequence of encrypted packets and the change-of-cell indication;

the cryptographic module is operative to perform, for each packet, the pre-calculation of the encrypting sequence and to perform, for each packet, a decryption using the corresponding pre-calculated encrypting sequence; and

further comprising:

circuits operative to determine information relating to the reception quality of the packets; and

a controller operative, for each packet, to activate the cryptographic module to perform the pre-calculation prior to the reception of the corresponding packet if the reception quality is greater than a threshold and if no change-of-cell indication is received.

14. The apparatus of claim 8 , wherein the data type is one of a control stream and a user stream.