Method for establishing a bidirectional communication channel between a server and a secure element, corresponding servers and secure element

1. A method for establishing a bidirectional communication channel between a server and a secure element cooperating with a terminal in a cellular telecommunication network for exchanging data and commands, said method comprising:

a—sending a first attachment request signaling message from said terminal to said server, said first message comprising a MCC and a MNC of said server, and in a field of a MSIN, a payload comprising data to be communicated to the server, these data representing at least a part of a unique identifier of said secure element, said unique identifier being an EID, an EID key or an ephemeral IMSI;

b—sending from said server to said secure element, in at least a first signaling message, instead of a standard RAND and/or AUTN message:

at least a command;

a correlation identifier if further messages have to be sent from said secure element to said server;

a first payload comprising data; and

c—executing at said secure element said command,

wherein said server comprises a SM-DS server that provisions the HSS of a MNO with a temporary IMSI transmitted to said secure element, along with an ephemeral key contained also in said secure element, thereby providing an improved SM-DS.

2. The method according to claim 1 , wherein a second signaling message also containing data is sent by said server with said first signaling message.

3. The method according to claim 1 , wherein said data contain a MCC and a MNC of a server of a MNO and a temporary IMSI permitting said secure element to attach to the network of said MNO.

4. The method according to claim 1 , wherein said correlation identifier is used for pairing messages exchanged between said server and said secure element and is changed at each sending of a new message by said server.

5. A server provisioned with an unique identifier of a secure element, said server comprising at least a microprocessor comprising instructions for:

a—receiving from a terminal cooperating with said secure element a first attachment request signaling message, said first attachment request signaling message comprising a MCC and a MNC of said server, and in a field of a MSIN, a payload comprising data to be communicated to the server, these data representing at least a part of a unique identifier of said secure element, said unique identifier being an EID, an EID key or an ephemeral IMSI;

b—sending in at least a first signaling message:

at least a command;

a correlation identifier if further messages have to be sent from said secure element to said server;

a first payload comprising data;

c—repeating steps a and b until said server has received the entire unique identifier from said secure element;

d—retrieving a temporary IMSI provisioned in a server of a MNO corresponding to said unique identifier; and

e—sending said temporary IMSI to said secure element with a command to replace its current IMSI by said temporary IMSI,

wherein said server comprises a SM-DS server that provisions the HSS of a MNO with a temporary IMSI transmitted to said secure element, along with an ephemeral key contained also in said secure element, thereby proving an improved SM-DS.

6. A secure element cooperating with a terminal and comprising an operating system comprising instructions to:

a—sending a first attachment request signaling message from said terminal to a server, said first message comprising a MCC and a MNC of said server, and in a field of a MSIN, a payload comprising data to be communicated to the server, these data representing at least a part of a unique identifier of said secure element, said unique identifier being an EID, an EID key or an ephemeral IMSI;

b—receive from said server, in at least a first signaling message:

at least a command;

a correlation identifier if further messages have to be sent from said secure element to said server;

a first payload comprising data;

c—executing at said secure element said command,

wherein said server comprises a SM-DS server that provisions the HSS of a MNO with a temporary IMSI transmitted to said secure element, along with an ephemeral key contained also in said secure element, thereby providing an improved SM-DS.

7. The secure element according to claim 6 , wherein said operating system:

sends to said server in at least a second attachment request signaling message, said MCC, said MNC, the correlation identifier received from said server and a second payload containing data and in that said operating system repeats steps -a- to -c- if necessary until said secure element and said server do not need to exchange further data or commands.

8. The secure element according to claim 6 , wherein it consists in:

an UICC, or

an eUICC, or

an iUICC.