Secure element, method for registering tokens, and token reference register

A method for registering tokens of an electronic transaction system comprising secure elements as transaction units, each token of the transaction system having at least one token value and one private part of a token-individual key pair acting as token elements, comprising the method steps:

• receiving registration requests in a token reference register of the transaction system, the registration requests each having at least two token references, with at least one token reference of a first registration request of the registration requests and one token reference of a second registration request of the registration requests being identical;
• verifying, using a verification unit of the token reference register, whether a token reference of a registration request can be uniquely assigned to a token of the transaction system, the token reference being checked to see whether it is or was stored in the token reference register;
• storing at least one token reference other than the checked token reference in the memory unit of the token reference register for registering the token uniquely assigned to this token reference in the transaction system if it is established in the verification step that a token of the transaction system can be assigned to the checked token reference;
• wherein in the receiving step, the registration requests are received in the token reference register as a sequence of registration requests, and in the verification and storage steps, the registration requests are processed in the token reference register as a sequence of registration requests.

A secure element as a subscriber unit in a transaction system having:

• an interface, configured for:
• transmitting token to another subscriber unit;
• transmitting, to a token reference register or a registration request unit of the transaction system, a registration request comprising at least a first and a second token reference;
• an access means to a token memory or token memories, wherein at least one token of the secure element is stored in the token memory;
• and
• a computing unit, configured for:
• applying a cryptographic one-way function to a private part of a token-individual key pair of a token of the token memory for obtaining a token reference;
• and
• modifying token.