Method for transmitting to a physical or virtual element of a telecommunications network an encrypted subscription identifier stored in a security element, corresponding security element, physical or virtual element and terminal cooperating with this security element
The invention concerns a method for transmitting to a physical or virtual element of a telecommunications network, an encrypted subscription identifier stored in a security element, or an encrypted identifier of the security element or an encrypted identifier of a terminal cooperating with the security element. The method includes pre-calculating proactively, at the occurrence of an event, the encrypted identifier using a key and storing it in a file or memory of the security element with a parameter enabling the key to be calculated by the element of the telecommunications network, in order to be able to transmit to the element of the telecommunications network the encrypted identifier and the parameter, without having to compute the encrypted identifier when the terminal is asking for it.
1. A method for transmitting to a physical or virtual element of a telecommunications network an encrypted subscription identifier stored in a security element, or an encrypted identifier of said security element or an encrypted identifier of a terminal cooperating with said security element, comprising pre-calculating proactively, at the occurrence a triggering event, said encrypted identifier using a key and storing it in a file or memory of said security element with a parameter enabling said key to be calculated by said element of said telecommunications network, in order to be able to transmit to said element of said telecommunications network said encrypted identifier and said parameter, without having to compute said encrypted identifier when said terminal is asking for it,
wherein each triggering event causes a computation of a new Subscription Concealed identifier (SUCI) within said security element and stored thereon, usable for a given authentication with, and before a registration request message is sent to, said physical or virtual element of the telecommunications network, formed by the equation:
Network (identifier) ID II Public key ID of the home network II encrypted MSIN,
where II represents a concatenation, said Network ID is a MCC/MNC (Mobile Country Code and Mobile Network Code that are not encrypted) and said MSIN (Mobile Station Identification Number) is a rest of an IMSI (said IMSI constituted by the MCC/MNC/MSIN).
2. The method as claimed in claim 1 , wherein said identifier is encrypted using an ECIES encryption scheme.
3. The method according to claim 1 , wherein said security element is a UICC, an eUICC, an iUICC or a hardware mediated execution environment.
4. The method according to claim 1 , wherein said encrypted identifier is pre-calculated responsive to each of the following triggering events:
Turning on said terminal;
Period of inactivity of said security element;
Selection of a file or memory or of a directory by said terminal;
Reading said file or memory containing said encrypted identifier by said terminal; and
Transmission of a previous encrypted identifier.
5. The method according to claim 1 , wherein an initial encrypted identifier to be used is stored in said security element in a personalization factory.
6. The method according to claim 1 , wherein more than one encrypted identifiers are pre-calculated and stored with corresponding parameters in said file or memory.
7. A security element comprising a processing circuit for pre-calculating an encrypted subscription identifier stored in said security element or an encrypted identifier of said security element or an encrypted identifier of a terminal designed to cooperate with said security element, said encrypted identifier being pre-calculated proactively at the occurrence of a triggering event using a key and stored in a file or memory of said security element with a parameter enabling said key to be calculated by a physical or virtual element of said telecommunications network in order to be able to transmit to said element of said telecommunications network said encrypted identifier and said parameter, without having to compute said encrypted identifier when said terminal is asking for it,
said encrypted identifier is pre-calculated responsive to each of the following triggering events:
Turning on said terminal;
Period of inactivity of said security element;
Selection of a file or memory or of a directory by said terminal;
Reading said file or memory containing said encrypted identifier by said terminal;
Transmission of a previous encrypted identifier,
wherein each triggering event causes a computation of a new Subscription Concealed Identifier (SUCI) within said security element and stored thereon, usable for a given authentication with, and before a registration request message is sent to, said physical or virtual element of the telecommunications network, formed by the equation:
Network (Identifier) ID II Public key ID of the home network II encrypted MSIN,
where II represents a concatenation, said Network ID is a MCC/MNC (Mobile Country Code and Mobile Network Code that are not encrypted) and said MSIN (Mobile Station Identification Number) is a rest of an IMSI (said IMSI) constituted by the MCC/MNC/MSIN).
8. Security element according to claim 7 , wherein said identifier is encrypted using an ECIES encryption scheme.
9. The Security element according to claim 7 , characterized in that it is a UICC, an eUICC, an iUICC or a hardware mediated execution environment.
10. The Security element according to claim 7 , wherein said processing circuit pre-calculates said encrypted identifier during one of the following events:
Turning on said terminal;
Period of inactivity of said security element;
Selection of a file or memory or of a directory by said terminal;
Reading said file or memory containing said encrypted identifier by said terminal;
Transmission of a previous encrypted identifier.
11. The Security element according to claim 7 , wherein said processing circuit pre-calculates more than one encrypted identifiers and stores them with corresponding parameters in said file or memory.
12. A physical or virtual element of a telecommunications network, comprising processing circuits for receiving from a security element an identifier encrypted by a key pre-calculated by said security element thereby producing an encrypted identifier stored in a file or memory of said security element with a parameter enabling said key to be calculated by said element of said telecommunications network,
said encrypted identifier is pre-calculated responsive to each of the following triggering events:
Turning on said terminal;
Period of inactivity of said security element;
Selection of a file or memory or of a directory by said terminal;
Reading said file or memory containing said encrypted identifier by said terminal;
Transmission of a previous encrypted identifier,
wherein each triggering event causes a computation of a new Subscription Concealed Identifier (SUCI) within said security element and stored thereon, usable for a given authentication with, and before a registration request message is sent to, said physical or virtual element of the telecommunications network, formed by the equation:
Network (Identifier) ID II Public key ID of the home network II encrypted MSIN,
where II represents a concatenation, said Network ID is a MCC/MNC (Mobile Country Code and Mobile Network Code that are not encrypted) and said MSIN (Mobile Station Identification Number) is a rest of an IMSI (said IMSI) constituted by the MCC/MNC/MSIN).
13. The physical or virtual element of a telecommunications network according to claim 12 , wherein it is constituted by an Home Subscriber Server (HSS) or by an Authentication Server Function (AUSF).