Cyphering of the content of a memory external to a processor
AssigneeSTMicroelectronics S.r.l.
InventorsStephan Courcambeck, Claude Anguille
Life of this patent
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Abstract
A method of cyphering by an integrated processor of a set of data to be stored in a memory, consisting of performing, in a continuous operation following a data flow, the steps of dividing the data flow into blocks of predetermined size and, for each block: generating a cyphering key by means of a pseudo-random generator implementing a continuous algorithm of cyphering according to a key specific to the integrated circuit and of an initialization vector changing for each block; combining the data block and the corresponding key in a continuous operation; and storing in said memory each cyphered block and the initialization vector used to cypher it.
Claims11
A method of cyphering by an integrated processor (30, 40) of a set of data to be stored in a memory (23), consisting of performing, in a continuous operation following a data flow, the steps of:
- dividing the data flow into blocks of predetermined size and, for each block:
- generating a cyphering key (Cb) by means of a pseudo-random generator (10) implementing a continuous algorithm of cyphering according to a key (K) specific to the integrated circuit and to an initialization vector (IV) changing for each block;
- combining the data block and the corresponding key (Cb) in a continuous operation;
- and
- storing in said memory (23) each cyphered block and the initialization vector used to cypher it.
A method for decyphering data blocks stored in a memory (23), consisting of performing the steps of:
- reading each block and an associated initialization vector from said memory (23);
- and
- applying, for each block, a continuous decyphering algorithm using, to generate a decyphering key (Cb), the initialization vector associated with the concerned block.
Dependencies are inferred from the claim text.