Method and system for initializing a data carrier as well as a method and system for restoring a user key

A method of restoring a user key, comprising:

• receiving a restoration request from a mobile device of a user at an issuer entity;
• verifying an identity of the user of the mobile device at the issuer entity;
• upon positive verification of the identity of the user of the mobile device, providing personalization data by the issuer entity;
• using the personalization data and a personalization entity key to generate a main shard by a secure element of a data carrier;
• establishing a connection between the mobile device and the data carrier;
• receiving at least a first shard from a first server entity by the secure element of the data carrier;
• restoring a user key based on the received first shard from the first server entity and the generated main shard.

A system or initializing a data carrier, comprising:

• an issuer entity configured to provide personalization data;
• a data carrier having a secure element configured to use the personalization data and a personalization entity key to generate a main shard;
• a mobile device configured to establish a connection to the data carrier;
• a first server entity and a second server entity;
• wherein the mobile device is configured to activate the data carrier by causing the secure element of the data carrier to generate at least a first shard and a second shard;
• wherein the mobile device is configured to retrieve the first shard and the second shard from the secure element of the data carrier and to transmit the first shard to the first server entity and the second shard to the second server entity;
• wherein the first server entity is configured to store the first shard and the second server entity is configured to store the second shard.

A system for restoring a user key, comprising:

• a mobile device;
• a data carrier having a secure element;
• an issuer entity configured to receive a restoration request from the mobile device and to verify an identity of a user of the mobile device;
• wherein the issuer entity is configured to provide personalization data upon positive verification of the identity of the user of the mobile device;
• wherein the secure element of the data carrier is configured to generate a main shard using the personalization data and a personalization entity key;
• wherein the mobile device is configured to establish a connection to the data carrier;
• wherein the secure element of the data carrier is configured to receive at least a first shard from a first server entity;
• wherein the mobile device is configured cause the secure element of the data carrier to restore a user key based on the received first shard and the generated main shard.