Secure method for secret key cryptographic calculation and component using said method
AssigneeSTMicroelectronics S.r.l.
InventorsFabrice Romain, Yannick Teglia
Life of this patent
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Abstract
A secured method of cryptographic computation to generate output data from input data and from a secret key includes a derived key scheduling step to provide a derived key from the secret key according to a known key scheduling operation. The method also includes a masking step, performed before the derived key scheduling step, to mask the secret key so that the derived scheduled key is different at each implementation of the method. The present method and component can be used in transfer type applications, such as bank type applications.
Claims12
A secured method of cryptographic computation to give an output data (MS) from an input data (ME) and from a secret key (K0), the method comprising several derived key scheduling step (ET2), to provide each an updated derived key. (M′1, M′i) from a previously computed derived key according to a known key scheduling law, a first updated derived key (M′1) being obtained from the secret key (K0),
- wherein the method also comprises a masking step (ET1), performed before a first key scheduling step (ET2), to mask the secret key (K0) so that the updated derived scheduled key (M′1, M′i) is different at each implementation of the method.
Dependencies are inferred from the claim text.