# US 2014/0195810 A1 · Secured method for controlling the opening of lock devices from messages implementing a symmetrical encryption

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- Number: US 2014/0195810 A1
- Document ID: US20140195810A1
- Status: Published application
- Kind: A1
- Application number: 14/050,392
- Filed: 2013-10-10
- Published: 2014-07-10
- Earliest claimed: 2012-10-11
- Assignees: Openways SAS
- Applicants: Openways SAS
- Inventors: Pascal METIVIER; Aitor AGUEDA
- Web page: https://patentgrep.com/patent/US20140195810A1

## CPC

- H04L 63/0435: {wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06)}
- G07C 9/00182: {operated with unidirectional data transmission between data carrier and locks}
- H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying}
- H04L 9/14: using a plurality of keys or algorithms
- G07C 2009/0023: {with encription of the transmittted data signal}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE

## Abstract

A management site (10) generates an encrypted message by a public-key symmetrical encryption algorithm, the algorithm and the key being selected by the management site among a memorized list. The message (DKE), which includes an identifier of the encryption algorithm and key used, is transmitted to a portable device (16), which stores it. For the use, the message is transmitted to a secured module (20) that decrypts it, checks its compliance with an internal reference, and generates a digital accreditation controlling the unlocking of a lock device (18). The decryption is operated with the algorithm and the key recognized based on the identifiers of the message, selected among a list memorized by the secured module.

## Claims

### Claim 1

A secured method for controlling the opening of lock devices, including the following steps:
a) by a management site (10):
a1) generation of digital data (DATA);
a2) encryption, according to a symmetrical method, of a field (40) containing said digital data, by an encryption algorithm and with an encryption key; and
a3) generation of a message (DKE) containing the encrypted field;
b) transmission of the message, via a communication network, to a portable device (16) held by a user and storage of this message in a memory of the portable device;
c) transmission of the message, by a short-range transmission technique, from the portable device (16) to a secured module (20) generator of digital accreditations, coupled to a lock device (18);
d) by the secured module (20) generator of digital accreditations, analysis of the message by:
d1) decryption, according to said symmetrical method, of the encrypted field (40);
d2) checking of the message compliance with an internal reference memorized in the secured module; and
d3) in case the message is proved compliant at step d2), generation by the secured module of a digital accreditation adapted to control the lock device unlocking upon recognition of the compliance of this accreditation,
the method being characterized in that:
said encryption and said decryption use a common key memorized both by the management site and by the secured module, the management site (10) and secured module (20) each memorizing (14, 24) a corresponding list of said common keys;
for the encryption of step a2), the manager site operates a previous selection of a key among said list of keys memorized by the management site;
the message generated at step a3) further contains an encryption key identifier (Kj), identifying the key used for the encryption of step a2), and
step d) comprises a step of previous reading of the encryption key identifier, and the decryption of step d1) is operated with the key identified by said reading, selected among said list of keys memorized by the secured module,
the method being also characterized in that it further comprises a procedure for updating, by substitution or/and addition of new keys, said list of keys memorized in a memory of the secured module, procedure in which:
during the generation of a message (DKE), the management site encapsulates into the encrypted field (40) of this message:
i) the new keys (Kn+1, Kn+2, . . . ), or
ii) an identifier of a modifying function selected among several modifying functions adapted to permit the calculation of the new keys;
the message is transmitted to the secured module addressee of the news keys via a portable device during an unlocking, by this portable device, of the lock coupled to this addressee secured module; and
upon reception of this message, the secured module:
i) updates the keys memorized in the memory of the secured module, or, respectively
ii) recalculates the new keys based on the received modifying function identifier, and updates the keys memorized in the memory of the secured module with the so-recalculated keys.

### Claim 2 (depends on 1)

The method of claim 1, wherein the software code of said modifying functions is memorized in a firmware of the secured module.

### Claim 3 (depends on 1)

The method of claim 1, wherein the selection by the management site of one key among said list of keys memorized is a pseudo-random selection.

### Claim 4 (depends on 1)

The method of claim 1, wherein the encryption key identifier (Kj) is contained in a non-encrypted field (30) of the message, or encrypted according to a predetermined mode, known by the secured module.

### Claim 5 (depends on 1)

The method of claim 1, wherein:
the management site (10) and the secured module (20) each memorize (14, 24) a corresponding plurality of encryption algorithms;
for the encryption of step a2), the management site operates a previous selection of an algorithm among said plurality of algorithms memorized in the management site;
the message generated at step a3) further contains an encryption algorithm identifier (ALi), identifying the algorithm used for the encryption of step a2), and
step d) comprises a step of previous reading of the algorithm identifier, and the decryption of step d1) is operated with the algorithm identified by said reading, selected among said plurality of algorithms memorized by the secured module.

### Claim 6 (depends on 5)

The method of claim 5, wherein the encryption algorithm identifier (ALi) is contained in a non-encrypted field (30) of the message, or encrypted according to a predetermined mode, known by the secured module.

### Claim 7 (depends on 1)

The method of claim 1, wherein a date of expiry is associated to each encryption key, and an updating procedure is automatically launched by the management site at least for said encryption key before said date of expiry.

### Claim 8 (depends on 1)

The method of claim 1, wherein:
it is further provided steps of:
generation by the management site, for a specific portable device, of a packet comprising a plurality of said messages,
transmission of this packet to this portable device, and
storage of the packet in a memory of the portable device;
the messages comprised in a same packet are all different and each contain:
an identifier of a lock device whose opening is authorized by said specific portable device, and
a sequencing marker associated with this lock device, and
the analysis of step d) comprises a checking:
of the fact that the message transmitted to the secured module by the portable device corresponds well to the lock device effectively coupled to this secured module, and
of the coherence of the sequencing marker contained in this message with a sequence number memorized in the secured module and constituting said internal reference.

### Claim 9 (depends on 8)

The method of claim 8, further comprising, in case the message is proved compliant at step d2), a step of:
e) updating of the sequence number memorized in the secured module, as a function of the sequencing marker contained in the received message.

### Claim 10 (depends on 8)

The method of claim 8, further comprising, in case the message is proved compliant at step d2), a step of:
f) if a previous authorization relating to a prior user is stored in the secured module, invalidation of this authorization.