Method for transmitting encrypted data, associated decrypting method, device for carrying out said methods and a mobile terminal for the incorporation thereof
First Claim
1. A method for transmitting encrypted data between a sender mobile terminal and at least one receiver mobile terminal of a digital radiocommunication system, through a radio transmission channel having a frame structure such that a TDMA frame comprises time slots of a first type forming a traffic channel for the transmission of traffic information and at least one time slot of a second type forming an associated signaling channel for the transmission of signaling information, wherein a sequence of encrypted data packets is transmitted in the traffic channel starting from a determined time slot of the first type whereas an associated cryptographic synchronization information cue is periodically transmitted in the associated signaling channel inside a determined time slot of the second type which is timely separated from said time slot of the first type by an undetermined time gap, and wherein a cryptographic synchronization delay information cue relating to said time gap is also periodically transmitted in the associated signaling channel.
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Accused Products
Abstract
A process for transmitting encrypted data through a radio transmission channel having a frame structure such that a TDMA frame comprises at least time slots of a first type forming a traffic channel and at least one time slot of a second type forming an associated signaling channel, comprises steps according to which:
- a sequence of encrypted data packets is transmitted in the traffic channel on the basis of a determined time slot of the first type, whereas an associated cryptographic synchronization information cue is transmitted in the associated signaling channel inside a determined time slot of the second type, and
- a cryptographic synchronization delay information cue relating to the time gap between said determined time slot of the second type and said determined time slot of the first type, is also transmitted in the associated signaling channel.
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Citations
29 Claims
- 1. A method for transmitting encrypted data between a sender mobile terminal and at least one receiver mobile terminal of a digital radiocommunication system, through a radio transmission channel having a frame structure such that a TDMA frame comprises time slots of a first type forming a traffic channel for the transmission of traffic information and at least one time slot of a second type forming an associated signaling channel for the transmission of signaling information, wherein a sequence of encrypted data packets is transmitted in the traffic channel starting from a determined time slot of the first type whereas an associated cryptographic synchronization information cue is periodically transmitted in the associated signaling channel inside a determined time slot of the second type which is timely separated from said time slot of the first type by an undetermined time gap, and wherein a cryptographic synchronization delay information cue relating to said time gap is also periodically transmitted in the associated signaling channel.
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9. A method for decrypting a sequence of encrypted data packets transmitted between a sender mobile terminal and at least one receiver mobile terminal of a digital radiocommunication system, through a radio transmission channel having a frame structure such that a TDMA frame comprises time slots of a first type forming a traffic channel for the transmission of traffic information and at least one time slot of a second type forming an associated signaling channel for the transmission of signaling information, comprising the steps of:
- receiving said sequence of encrypted data packets starting from a determined time slot of the first type;
optionally, periodically receiving an associated cryptographic synchronization information cue in the associated signaling channel, inside a determined time slot of the second type which is timely separated from said time slot of the first type by an undetermined time gap, and, in this case, also periodically receiving, in the associated signaling channel, a cryptographic synchronization delay information cue relating to said time gap;
generating a value of an initialization vector having served to generate a cryptographic sequence used for the encryption of said sequence of encrypted data packets;
generating the same cryptographic sequence, on the basis of the initialization vector value generated in;
said step of generating a value of an initialization vector;
shifting the cryptographic sequence generated in said step of generating the same cryptographic sequence as a function of said cryptographic synchronization delay information cue; and
decrypting said sequence of encrypted data packets on the basis of said shifted cryptographic sequence. - View Dependent Claims (10, 11, 12, 13)
- receiving said sequence of encrypted data packets starting from a determined time slot of the first type;
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14. A device for transmitting encrypted data between a sender mobile terminal and at least one receiver mobile terminal of a digital radiocommunication system, through a radio transmission channel having a frame structure such that a TDMA frame comprises time slots of a first type forming a traffic channel for the transmission of traffic information and at least one time slot of a second type forming an associated signaling channel for the transmission of signaling information, comprising:
- means for transmitting a sequence of encrypted data packets in the traffic channel starting from a determined time slot of the first type, and for periodically transmitting an associated cryptographic synchronization information cue in the associated signaling channel inside a determined time slot of the second type which is timely separated from said time slot of the first type by an undetermined time gap, and means for also periodically transmitting in the associated signaling channel, a cryptographic synchronization delay information cue relating to said time gap.
- View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 27, 29)
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22. A device for decrypting a sequence of encrypted data packets transmitted between a sender mobile terminal and at least one receiver mobile terminal of a digital radiocommunication system, through a radio transmission channel having a frame structure such that a TDMA frame comprises time slots of a first type forming a traffic channel for the transmission of traffic information and at least one time slot of a second type forming an associated signaling channel for the transmission of signaling information, comprising:
- first means of reception for receiving said sequence of encrypted data packets starting from a determined time slot of the first type;
second means of reception for, optionally, periodically receiving an associated cryptographic synchronization information cue in the associated signaling channel, inside a determined time slot of the second type which is timely separated from said time slot of the first type by an undetermined time gap, and, in this case, means of reception for also periodically receiving, in the associated signaling channel, a cryptographic synchronization delay information cue relating to said time gap;
first means of generation for generating a value of an initialization vector having served to generate a cryptographic sequence used for the encryption of said sequence of encrypted data packets;
second means of generation, for generating the same cryptographic sequence on the basis of the initialization vector value generated by said first means of generation;
means of shifting for shifting the cryptographic sequence generated by said second means of generation, as a function of said cryptographic synchronization delay information cue; and
means for decrypting said sequence of encrypted data packets on the basis of said shifted cryptographic sequence. - View Dependent Claims (23, 24, 25, 26, 28)
- first means of reception for receiving said sequence of encrypted data packets starting from a determined time slot of the first type;
Specification