Method for securing updating data from a plurality of devices, each device receiving the updates from a managing center, these updates (P R) allowing to change the device initial version N to a final version R, the difference (R-N) between the initial version N and the final version R exceeding the unit, these updates (P R) being accompanied by a control block comprising a signature (H(P R))PK R associated with said update, this signature (H(P R))PK R being encrypted by a private asymmetrical key (PK R) stored in the managing center, the corresponding list of the asymmetric keys being stored in the device, characterized by following steps: a) preparing by the managing center of series of messages (M 1...M R-1), each message being encrypted with an asymmetric current key (PK 1...PK R-1) and sending the series of messages (M 1...M R-1) encrypted to the device, b) receiving said messages (M 1...M R-1) by the device and using the current corresponding key (K 1...K R-1) for decrypting each message (M 1...M R-1), c) if the decryption of the message with the current key is successful, deactivation of the current corresponding key (K 1...K R-1) and activating of the current key (K R) corresponding to the version of the update (P R), d) preparing by the managing center of the update (P R) and of its signature (H(P R))PK R encrypted with the current asymmetric key (PK R) and transmitting to the device, said transmission does not comprise indication allowing to the device to select one asymmetric key in its list of asymmetric keys, e) receiving the update (P R) and the signature (H(P R))PK R by the device, f) using the current corresponding key (K R) for the decryption of the signature (H(P R))PK R to obtain a first digest H(P R) 1 expected of the update (P R), g) verifying the conformity of the update (P R) by the calculation of a second digest H(P R) 2 on the update (P R) and comparing the first and the second digest, h) deactivation of the corresponding current key (K R) of the device and activation of the next key (K R+1), said corresponding current key (K R) being unavailable for all future use, said deactivation being performed after each use of a key. a) preparing by the managing center of series of messages (M 1...M R-1), each message being encrypted with an asymmetric current key (PK 1...PK R-1) and sending the series of messages (M 1...M R-1) encrypted to the device, b) receiving said messages (M 1...M R-1) by the device and using the current corresponding key (K 1...K R-1) for decrypting each message (M 1...M R-1), c) if the decryption of the message with the current key is successful, deactivation of the current corresponding key (K 1...K R-1) and activating of the current key (K R) corresponding to the version of the update (P R), d) preparing by the managing center of the update (P R) and of its signature (H(P R))PK R encrypted with the current asymmetric key (PK R) and transmitting to the device, said transmission does not comprise indication allowing to the device to select one asymmetric key in its list of asymmetric keys, e) receiving the update (P R) and the signature (H(P R))PK R by the device, f) using the current corresponding key (K R) for the decryption of the signature (H(P R))PK R to obtain a first digest H(P R) 1 expected of the update (P R), g) verifying the conformity of the update (P R) by the calculation of a second digest H(P R) 2 on the update (P R) and comparing the first and the second digest, h) deactivation of the corresponding current key (K R) of the device and activation of the next key (K R+1), said corresponding current key (K R) being unavailable for all future use, said deactivation being performed after each use of a key.