Patent ID: 7116783

Claim:
A method for secured transfer of an N-byte secret data element from a first memory containing the secret data element to a second memory through a data bus that is connected between the first memory and the second memory, said method comprising the steps of: transferring the N-byte secret data element byte-by-byte from the first memory to the second memory through the data bus with the bytes of the N-byte secret data element being transferred through the data bus in an order that is randomly chosen and each byte transiting at least once through the data bus, wherein the transferring step includes the sub-steps of: before each transfer of one of the bytes of the N-byte secret data element, randomly choosing a current index ranging from 0 to N−1, the current index corresponding to a place value of the byte of the N-byte secret data element to be transferred, at each transfer of one of the bytes of the N-byte secret data element, transferring the byte of the N-byte secret data element with a place value equal to the current index and modifying a corresponding bit of a loading indicator as a function of a loading mode, the loading mode being an integer ranging from 0 to a first constant; and ending the transfer of the N-byte secret data element when the loading indicator takes a predetermined value.