Data transfer system and transfer method

Patent metadata

Field	Value
Publication number	US-11290257-B2
Application number	US-201916380621-A
Country	US
Kind code	B2
Filing date	Apr 10, 2019
Priority date	May 1, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

To securely realize updating of a key shared between an apparatus on a transmission side and an apparatus on a reception side. A second apparatus encrypts a new shared key by an encryption processing unit, issues a signature for the encrypted new shared key from a signature processing unit, and transmits the signature and the encrypted new shared key to a first apparatus. When a signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit at least one of processing executed after reception of the encrypted new shared key and required to store the new shared key into a storage unit.

First claim

What is claimed is:

1. A data transfer system comprising:
a first apparatus having a first encryption processing unit, a first signature processing unit, and a first storage unit configured to store a shared key decrypted by the first encryption processing unit; and
a second apparatus having a second encryption processing unit and a second signature processing unit,
wherein the second apparatus encrypts a new shared key by the second encryption processing unit, issues a signature for the encrypted new shared key from the second signature processing unit, and transmits the signature and the encrypted new shared key to the first apparatus,
wherein when the first signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit at least one of processing executed after reception of the encrypted new shared key and required to store the new shared key into the first storage unit,
wherein when a transfer to the first apparatus is continuously performed N times (where N is an integer of 2 or more), the second apparatus processes and transfers transfer data including a jth signature shared key and encryption shared key used for a jth transfer by using a j−1th signature shared key and encryption shared key in a j−1th transfer (where j is an integer of 2 or more and N or less),
wherein the first apparatus transfers to the second apparatus, transfer data including the number of times of consecutive success of transfers counted from a first transfer of the transfer data, and the latest signature shared key and encryption shared key which are encrypted by the second encryption processing unit using a pre-shared key shared in advance between the first apparatus and the second apparatus and which are obtained from the second apparatus by the first apparatus, and
wherein the second apparatus decrypts the transfer data transferred from the first apparatus by using the pre-shared key, and executes again transfers of the number of times next and subsequent to the number of times of the consecutive success of the transfers by using for the first transfer of retransfers, the signature shared key and the encryption shared key obtained by the decryption.

2. The data transfer system according to claim 1 , wherein when the first signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit decryption of the encrypted new shared key by the first encryption processing unit.

3. The data transfer system according to claim 1 ,
wherein the first storage unit includes a nonvolatile memory that stores the shared key and a buffer memory that temporarily stores the shared key, and
wherein when the first signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit storage of the new shared key decrypted by the first encryption processing unit into the buffer memory.

4. The data transfer system according to claim 1 ,
wherein the first storage unit includes a nonvolatile memory that stores the shared key and a buffer memory that temporarily stores the shared key, and
wherein when the first signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit storage of the new shared key decrypted by the first encryption processing unit and stored in the buffer memory into the nonvolatile memory.

5. The data transfer system according to claim 1 ,
wherein the first storage unit includes a first buffer memory temporarily storing a shared key therein,
wherein the second apparatus has a second storage unit including a second buffer memory temporarily storing a shared key therein, and
wherein the first buffer memory and the second buffer memory respectively include a first surface and a second surface, one of which stores a shared key used for a current transfer, and the other of which stores a new shared key used for a next transfer.

6. The data transfer system according to claim 1 , wherein the transfer data including the number of times of the consecutive success, and the signature shared key and the encryption shared key is transferred, the first apparatus and the second apparatus adopt the signature shared key or the encryption shared key as a new pre-shared key.

7. A data transfer system comprising:
a first apparatus having a first encryption processing unit, a first signature processing unit, and a first storage unit configured to store a shared key decrypted by the first encryption processing unit; and
a second apparatus having a second encryption processing unit and a second signature processing unit,
wherein the second apparatus encrypts a new shared key by the second encryption processing unit, issues a signature for the encrypted new shared key from the second signature processing unit, and transmits the signature and the encrypted new shared key to the first apparatus,
wherein when the first signature processing unit fails in verifying the signature, the first apparatus performs control to prohibit at least one of processing executed after reception of the encrypted new shared key and required to store the new shared key into the first storage unit,
wherein the first apparatus further includes a first pseudo random number generating unit which generates a cryptographical pseudo random number uniquely determined by a predetermined key, a predetermined random number, and an arbitrary counter value,
wherein the second apparatus further includes a second pseudo random number generating unit which generates a cryptographical pseudo random number uniquely determined by the predetermined key, the predetermined random number, and an arbitrary counter value,
wherein the counter values used in the first pseudo random number generating unit and the second pseudo random number generating unit are values respectively changed by a predetermined value for each transfer,
wherein when a transfer to the first apparatus is continuously performed N times (where N is an integer of 2 or more), the second apparatus processes and transfers transfer data including a jth signature shared key and encryption shared key used for a jth transfer by using a j−1th signature shared key and encryption shared key in a j−1th transfer (where j is an integer of 2 or more and N or less),
wherein the jth signature shared key and encryption shared key are cryptographical pseudo random numbers generated by the first pseudo random number generating unit, and
wherein when the first apparatus fails in obtaining the signature shared key and the encryption shared key transmitted in the j−1th transfer from the second apparatus, the first apparatus generates the signature shared key and the encryption shared key used for the jth transfer from the first pseudo random number generating unit.

8. The data transfer system according to claim 7 ,
wherein upon each transfer, the second apparatus transmits to the first apparatus, a signature for the counter value managed by the second apparatus as well, which is generated by the second signature processing unit by using a pre-shared key shared in advance between the first apparatus and the second apparatus, and
wherein when the signature shared key and the encryption shared key used for the jth transfer are generated by the first pseudo random number generating unit, the first apparatus generates the signature shared key and the encryption shared key used for the jth transfer from the first pseudo random number generating unit where the signature transmitted from the second apparatus passes verification by the first signature processing unit using the counter value managed by the second apparatus and the pre-shared key.

9. The data transfer system according to claim 8 ,
where

Assignees

• Renesas Electronics Corp

Inventors

• Tanimoto Tadaaki
• Moriyama Daisuke

Classifications

• G06F21/602

  Providing cryptographic facilities or services · CPC title

• G06F7/582

  Pseudo-random number generators · CPC title

• H04L9/0819 Primary

  Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) (network architectures or network communication protocols for key distribution in a packet data network H04L63/062) · CPC title

• H04L9/0822 Primary

  using key encryption key · CPC title

• H04L9/0825

  using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates · CPC title