Method and Device For the Encryption and Decryption of Data
AssigneeFrance Telecom
InventorsPascal Nourry, Stephanie Relier, Francois Daude
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Abstract
Digital data blocks are encrypted, each data block that is to be encrypted being associated with a time reference. A value of an initialization vector VI and an encryption key K are defined. Then, a counter C is obtained for each data block to be encoded, by combining the time reference and the value of the initialization vector. A series of binary encryption elements is obtained via an encryption function taking the encryption key K and counter C as input parameters. The data block is then encrypted by combining it with the series of binary encryption elements.
Claims17
A method of encrypting digital data blocks, each data block to be encrypted being associated with a time reference, following which a value of an initialization vector VI and an encryption key K are defined,
- said method comprising, for each data block to be encrypted, steps consisting in:
- obtaining a counter C, by combining said time reference and said value of the initialization vector;
- obtaining a series of encryption bits via an encryption function taking said encryption key K and said counter C as input parameters;
- encrypting said data block by combining it with said series of encryption bits.
The method as claimed in any one of the preceding claims, wherein combining the time reference and the value of the initialization vector comprises an exclusive OR operation.
The method as claimed in any one of the preceding claims, wherein combining the data block to be encrypted and the series of encryption bits comprises an exclusive OR operation.
The method as claimed in any one of the preceding claims, wherein the encryption function is an AES-type function.
The method as claimed in any one of the preceding claims, wherein the data blocks to be encrypted are multimedia data blocks.
The method as claimed in any one of the preceding claims, wherein the data block to be encrypted is subdivided into a plurality of sub-blocks of determined fixed length, the final sub-block being of shorter length if necessary, and
- wherein each of said sub-blocks is encrypted, one sub-block at a time.
A device for encrypting digital data blocks, each data block to be encrypted being associated with a time reference, wherein a value of an initialization vector VI and an encryption key K are defined,
- said device comprising means arranged to implement an encryption method as claimed in any one of the preceding claims.
Dependencies are inferred from the claim text.