Protecting against differential power analysis attacks on decryption keys
AssigneeXilinx, Inc.
InventorStephen M. Trimberger
Life of this patent
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Abstract
An embodiment of a method is disclosed for protecting a key from discovery during decryption of a data stream. This embodiment of the method includes decrypting the data stream with the key. Before completing decryption of the data stream, the method checks consistency between a decrypted portion of the data stream and expected data using a circuit arrangement. In response to an inconsistency between the decrypted portion and the expected data, a tampering signal is generated to indicate tampering is suspected.
Claims20
A method for protecting a key from discovery during decryption of a data stream, comprising:
- decrypting the data stream with the key;
- before completing decryption of the data stream, checking consistency between a decrypted portion of the data stream and expected data using a circuit arrangement;
- and
- in response to an inconsistency between the decrypted portion and the expected data, generating a tampering signal that indicates tampering is suspected.
A decryption system, comprising:
- a decryption controller configured to provide an input encrypted data stream and a decryption key;
- a decryptor circuit coupled to receive the input data stream and the decryption key, the decryptor circuit configured to decrypt the input data stream with the decryption key and generate a decrypted data stream;
- and
- a consistency check circuit coupled to receive the decrypted data stream from the decryptor circuit and coupled to the decryption controller, wherein the consistency check circuit is configured to check consistency, before the decryptor circuit completes decryption of the input data stream, between a portion of the decrypted data stream and expected data, and generate a tampering signal indicating tampering is suspected in response to finding an inconsistency.
Dependencies are inferred from the claim text.