Patent ID: 11880832
Assignee: THALES DIS FRANCE SAS
Field: Digital communication (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A method for enhancing security of a communication device when conducting a transaction, defined by transaction data, using a transaction application of the communication device by receiving transaction session keys from a key management server via a remote server, the method comprising:
generating, by the key management server, account parameters included in a provisioning package by:
generating, using a reversible function, a bound session cryptographic key by binding a session cryptographic key to a specific context defined as at least a first binding preventing data related to the transaction wherein said binding of said session cryptographic key to said first binding preventing data prevents unauthorized use or access of the session cryptographic key as any deviation from the specific context used to generate the bound session cryptographic key corrupts the session cryptographic key during a subsequent unbinding phase;
generating a transport key;
encrypting the bound session cryptographic key with the transport key;
encrypting the transport key with a static key stored on the communication device or retrievable by the communication device;
incorporating the encrypted bound session cryptographic key and the encrypted transport key into the provisioning package;

transmitting, by the key management server, the provisioning package to the remote system;
transmitting, by the remote system, the provisioning package to the communication device,
computing a transaction cryptogram, by the communication device, wherein the step of computing a transaction cryptogram comprises:
receiving the provisioning package from the remote server;
retrieving the static key;
recovering the transport key by decrypting the encrypted transport key received in the provisioning package using the static key;
recovering the bound session cryptographic key received in the provisioning package using the recovered transport key;
determining first unbinding preventing data; and
unbinding the session cryptographic key from the specific context using the determined first unbinding preventing data using an inverse function of the reversible function, whereby a determined unbinding preventing data not equal to the binding preventing data results in a corrupted unbound session cryptographic key whereas a determined preventing data equal to the binding preventing data results in an unbound session cryptographic key that is not corrupted;
computing the transaction cryptogram using a one-way cryptographic hash function to the transaction data using the unbound session cryptographic key, wherein the transaction is authorized or rejected based on whether the computed transaction cryptogram is an expected transaction cryptogram or a not expected transaction cryptogram.