Method for transmitting data, method for receiving data, corresponding devices and programs
View Patent ↗The disclosure relates to a method for transmitting data and to a corresponding method for receiving data. According to the disclosure, in the method for transmitting data, a cryptographic processing operation is performed on the data to be transmitted, after this data has been pre-subdivided into blocks of data, and a tag representing each block of encrypted data is computed. The tag is then transmitted in such a way that a hacker in not able to reproduce a correct transmission of tags. The method of reception, for its part, ensures that when an incorrect tag is received (because of a hacking attempt), the processing of the data blocks is not immediately stopped but a differential processing is implemented in order to jam an attempt to analyze the behavior of the receiver.
1. A method for transmitting data implemented by a first electronic device, called a sender, to a second electronic device, called a receiver, method comprising transmitting a message subdivided into blocks of data wherein the method comprises at least one iteration of:
obtaining of a block of current data A i ;
encrypting said block of current data A i , by means of an encryption key k, delivering a block of encrypted data C i ;
determining a tag b i , having a random or pseudo-random length, as a function of said block of encrypted data C i , the length of the tag b i being obtained by implementing a secret function based on the encryption key k;
transmitting of said block of encrypted data C i ;
and wherein the method comprises transmitting at least one tag b i according to a predetermined transmission scheme.
2. The method for transmitting according to claim 1 , wherein the transmitting of at least one tag is performed at each iteration of the processing of a block of data A i .
3. The method for transmitting according to claim 1 , wherein the size of said tag b i is from 1 bit to 8 bits.
4. The method for transmitting according to claim 1 , wherein said method for transmitting comprises, prior to the processing of a block of data A i , obtaining an encryption key k, called a session key.
5. A method for receiving data representing a message subdivided into blocks of data, method implemented by an electronic device called a receiver device, wherein the method comprises at least one iteration of:
receiving a block of encrypted data C i corresponding to a block of data A i of the message encrypted by means of an encryption key k;
receiving a tag b i corresponding to a signature of said block of encrypted data C i , said tag b i having a random or pseudo-random length obtained by implementing a secret function based on the encryption key k;
verifying a validity of said received tag b i relative to an expected tag b iA ; and
when said received tag b i is different from said expected tag b iA , differentially processing at least one previously received valid block of encrypted data.
6. The method for receiving data according to claim 5 , wherein said receiving of a block of encrypted data C i comprises inserting said block of encrypted data C i into a first queue of a predetermined size.
7. The method for receiving data according to claim 5 , wherein said differentially processing at least one previously received valid block of encrypted data comprises:
determining a location of invalidation j, within a second queue;
processing data inserted into the second queue up to the location of invalidation j;
stopping the processing.
8. An electronic data transmission device, called a sender, for transmitting data to be sent to a second electronic device called a receiver, a message subdivided into blocks of data, wherein the electronic device comprises a data processor and a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the data processor configure the device to perform acts comprising:
obtaining a block of current data A i ;
encrypting said block of current data A i by means of an encryption key k, delivering a block of encrypted data C i ;
determining a tag b i , having a random or pseudo-random length, as a function of said block of encrypted data C i , the length of the tag b i being obtained by implementing a secret function based on the encryption key k; and
transmitting said block of encrypted data C i ;
wherein the electronic device transmits at least one tag b i according to a predetermined transmission scheme.
9. An electronic device, called a receiver device, for receiving data representing a message subdivided into blocks of data wherein the electronic device comprises a data processor and a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the data processor configure the device to perform acts comprising:
receiving a block of encrypted data C i corresponding to a block of data A i of the message encrypted by means of an encryption key k;
receiving a tag b i corresponding to a signature of said block of encrypted data C i , said tag b i having a random or pseudo-random length obtained by implementing a secret function based on the encryption key k;
verifying a validity of said received tag b i relative to an expected tag IDA; and
differentially processing at least one previously received valid block of encrypted data, implemented when said received tag b i is different from said expected tag b iA .