Method for registering of token, a token reference register, secure transaction unit, and electronic payment transaction system

1 . A method for registering a token of an electronic payment transaction system, wherein each token comprises at least a monetary value and a private key of a token-individual key pair as token elements, the method comprising the steps of:

receiving, at a token reference register of the electronic payment transaction system, a registration request, the registration request being an addition registration request requesting addition of at least one token reference to be stored in the token reference register or a replacement registration request requesting replacement of at least one token reference to be stored in the token reference register for at least one token reference to be replaced in the token reference register, wherein the at least one token reference to be stored is an output token reference and the at least one token reference to be replaced is an input token reference, the registration request comprising at least one token reference, wherein each token reference is uniquely assigned to a token, wherein each token reference comprises a hash value as a token reference element that is directly or indirectly derived from the private key of the token-individual key pair or directly derived from a public key of the token-individual key pair, wherein each output token reference does not comprise the public key, and wherein each input token reference comprises the public key;

verifying, by a verification unit of the token reference register, whether at least one criteria in the token reference register is met for the received registration request; and

storing, in a storage unit of the token reference register, the output token reference of the received registration request for registering the token uniquely assigned to this token reference, in case the at least one criteria is met for the received registration request.

2 . The method according to claim 1 , wherein

the at least one token reference comprises a hash value that is directly computed from a public key of the token-individual key pair as the token reference element; or

the at least one token reference comprises a hash value that is directly computed from the private key of the token-individual key pair as the token reference element.

3 . The method according to claim 1 , wherein the hash value is derived as a result from a SHA-512-algorithm or a SHA-256-algorithm.

4 . The method according to claim 1 , wherein the token reference further comprises the monetary value of the uniquely assigned token.

5 . The method according to claim 1 , wherein the addition request is received from a secure token issuing unit of a token issuer of the transaction system, requesting the addition of a token reference of a new token to the token reference register; or

the replacement registration request is received from a transaction unit of the transaction system, requesting at least one input token reference, m input token references stored in the token reference register to be replaced in the token reference register by n output token references.

6 . The method according to claim 1 , wherein the step of verifying comprises:

verifying whether the output token reference of the received registration request is not already stored in the storage unit of the token reference register; and/or

verifying whether the input token reference(s) of the received registration request is stored in the storage unit of the token reference register; and/or

verifying whether the received registration request is not already stored in an archive of previous registration requests in the token reference register.

7 . The method according to claim 1 , wherein the verification unit further verifies the correctness of the received registration request,

by performing one or more of the following substeps:

for each input token reference in the received replacement registration request, the input token reference being assigned to an input token, verifying whether a signature in the registration request was created by the private key of the respective input token; and/or

for each input/further token reference in the received replacement registration request verifying whether the hash value of the input token reference can be rederived from the public key included in the received replacement registration request; and/or

verifying whether the received replacement registration request is value-neutral, by comparing the monetary value of (all) input token reference(s) and the monetary value of (all) output token reference(s) of the replacement registration request; and/or

verifying whether the addition registration request is signed by a secure token issuing unit.

8 . A token reference register for registering of token of an electronic payment transaction system, the token reference register comprising at least one processor, a memory storing a token reference database, and a communication interface configured to receive the registration request, wherein the at least one processor is configured to execute the method steps of claim 1 .

9 . The token reference register of claim 8 , wherein the at least one processor is configured to execute a verification module for performing the verifying step for the received registration request, and a new-registration module for registering of one or more new tokens that are created by a token issuer or for deregistering of one or more old tokens that are deleted by the token issuer, and wherein the memory further stores an archive of previous registration requests.

10 . A secure transaction unit for managing payment transactions in an electronic payment transaction system, the secure transaction unit comprising:

a communication interface configured to receive and transmit one or more tokens, wherein each token comprises at least a monetary value and a private key of a token-individual key pair as token elements; and

at least one processor and a secure memory storing instructions that, when executed by the at least one processor, cause the secure transaction unit to generate one or more token references, wherein each token reference is uniquely assigned to a token and wherein each token reference comprises a hash value as a token reference element that is directly or indirectly derived from a private key of a token-individual key pair or directly derived from a public key of the token-individual key pair, wherein each output token reference of the one or more token references does not comprise the public key, and wherein each input token reference of the one or more token references comprises the public key.

11 . The secure transaction unit of claim 10 , wherein the at least one processor is configured to cause a direct exchange of one or more tokens with one or more other secure transaction units in the electronic transaction system, and send registration requests including the generated token references to a token reference register of the electronic transaction system for registering the tokens in the electronic payment transaction system.

12 . The secure transaction unit according to claim 10 , wherein the secure transaction unit is a secure element that is operatively connected to an electronic equipment of a participant in the electronic payment system; or

wherein the secure transaction unit is a secure wallet that is hosted at a service provider unit.

13 . The secure transaction unit according to claim 10 , wherein the secure memory comprises a token storage storing one or more tokens.

14 . The secure transaction unit according to claim 10 , wherein the hash value is derived as a result from a SHA-512-algorithm or a SHA-256-algorithm.

15 . An electronic payment transaction system comprising:

a secure token issuing unit comprising at least one processor and a memory storing instructions that, when executed by the at least one processor, cause the secure token issuing unit to:

generate a new token to be issued in the electronic transaction system; and

delete tokens to be deleted from the electronic transaction system; and

a plurality of secure transaction units according to claim 10 ; and

one or more token reference register for registering the tokens of the electronic transaction system.