METHOD OF MODIFYING SECRETS INCLUDED IN A CRYPTOGRAPHIC MODULE, NOTABLY IN AN UNPROTECTED ENVIRONMENT

• US 20100135496A1
• Filed: 02/27/2008
• Published: 06/03/2010
• Est. Priority Date: 03/06/2007
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: D'athis, Thierry, Dailly, Philippe, Ratier, Denis
• Granted Patent: US 8,411,864 B2
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06F 21/77 in smart cards
• CPC Class Codes: G06F 2221/2129 Authenticate client device independently of the user

Abstract

The invention relates to a method for modifying a set of secrets in a crypto-graphic module. The cryptographic module ensures that the loading of a secret is either complete or null and void. The module enables a reading of a version number for each secret. The module includes information indicating a version number corresponding to the set of secrets. The method of the invention includes a first step during which, if the version number of the set of secrets is equal to a version number that requires the loading of a set of new secrets, the version number of the set of secrets in the cryptographic module is made equal to a distinctive number that determines that the cryptographic module is being uploaded. The method comprises a second step during which, for each secret and if the version number of said secret is different from the version number of the corresponding new secret to be downloaded, the new secret and the version number thereof are loaded. The method comprises a third step during which the version number of the set of secrets in the cryptographic module is made equal to the version umber of the set of new secrets. The invention can be used particularly for downloading access keys included in a set of smart cards in a non-protected environment.

Claims

1. A method of modifying secrets included in a cryptographic module on a card, the cryptographic module including a version number that corresponds to a set of secrets, wherein the cryptographic module:

indicates whether a loading of a secret is either successful, or invalid; and

allows reading of a version number for each secret;

wherein the method comprises the steps of;

assigning a distinctive number to the version number of the set of secrets of the cryptographic module, if the version number of the set of secrets is equal to a version number that requires a set of new secrets to be loaded, in order to indicate that the cryptographic module is being reloaded;

for each secret, loading said new secret and its version number if the version number of the secret is different from the version number of the corresponding new secret to be loaded;

assigning the version number of the set of new secrets to the version number of the set of secrets of the cryptographic module.

2. The method as claimed in claim 1, wherein the version number of the set of secrets of the cryptographic module on the card is recorded in a file of the cryptographic module of the card accessible via an immutable secret.

3. The method as claimed in claim 1, wherein the version number of the set of secrets of the cryptographic module on the card is recorded as a secret used to indicate a global version of the secrets.

4. The method as claimed in claim 1, wherein the version number of the set of secrets of the cryptographic module on the card is recorded as the last of the secrets to be reloaded in the step of loading the new secret and its version number.

5. The method as claimed in claim 1, wherein the step of loading said new secret and its version number comprises verifying the version number of each secret by mutual authentication of one or more secrets until an interruption point is found.