Encryption process protected against side channel attacks
AssigneeInside Secure
InventorsBenoît Feix, Mylène Roussellet
Life of this patent
Estimating the term…
Abstract
The invention relates to a symmetric encryption process executed by a microcircuit to transform a message into an encrypted message from a secret key, the process including a first round, intermediary rounds, and a last round. According to the invention, the process includes several executions of the first round and of the last round, and a number of executions of at least one intermediary round, the number of executions being less than the number of executions of the first and last rounds. The invention is particularly applicable to DES, Triple DES, and AES processes.
Claims15
Symmetric encryption process (CP3, CP4) executed by a microcircuit (MCT) to transform a message (M) into an encrypted message (C) from a secret key (K, K0), comprising a first round (RDA intermediary rounds (RD2, RDi, RDNr-1), and a last round (RDNr),
- characterized in that it comprises several executions (N1, NNr) of the first round and of the last round, respectively from the secret key (K, K0) and from a first set of false keys (K1−KN1-1), and a number of executions (N1), of at least one intermediary round (RD) less than the number of executions (N1, NNr) of the first and last rounds, respectively from the secret key and from a set of false keys (K1−KNi-1) included in the first set of false keys.
Microcircuit (MCT) configured to execute a symmetric encryption process (CP3, CP4) to transform a message (M) into an encrypted message (C) from a secret key (K, K0), the process comprising a first round (RDA1), intermediary rounds (RD2, RDi, RDNr-1), and a last round (RDNr),
- characterized in that the microcircuit is configured to execute several times (N1, NNr) the first round and the last round, respectively from the secret key and from a first set of false keys (K1−KN1-1), and to execute at least one intermediary round (RDi) a number of times (Ni) less than the number of executions (N1, NNr) of the first and last rounds, respectively from the secret key and from a set of false keys (K1−KNi-1) included in the first set of false keys.
Dependencies are inferred from the claim text.