Aging of electronic payment units

1. An electronic purse data carrier for performing monetary transactions, comprising

a storage means for storing one or more payment units each having a respective monetary value, each of said payment units comprising an age information valuable for delimiting the use of the payment unit, and each of said payment units having a respective unique payment unit-ID, in which said age information reflects the extent of transactional use of the respective payment unit, and in which said age information represents a date information;

a processor for read and/or write access to said storage means, and means for updating said age information whenever a transaction has been performed with a respective payment unit;

means for splitting a parent payment having given non-minimum parent non-minimum monetary value into a plurality of child payment units each having a child monetary value smaller than the parent value, the sum of child monetary values being the same as the parent monetary value, and means for transferring a respective age information from said parent unit to the plurality of child payment units, means for joining a plurality of single payment units having a given total monetary value into a joined payment unit having a corresponding same monetary value, and means generating a resulting age information for said joined payment unit according to a predetermined rule, said means for transferring a respective age information further excluding said one or more payment units having a monetary value smaller than a predetermined value from inheriting age information, said means for transferring a respective age information further excluding said one or more payment units that have exceeded a predetermined change threshold age level from a split or join process.

2. The carrier according to claim 1 , further comprising means for generating a patching pattern for splitting and/or joining payment units according to storage requirements present on the carrier.

3. The carrier according to claim 1 , further comprising means for excluding a payment unit from an intended split or join process if said payment unit has exceeded a predetermined change threshold age level.

4. The carrier according to claim 3 further comprising a plurality of payment units of different monetary value.

5. The carrier according to claim 1 further comprising means for storing personal Identification Data associated with one or more payment units.

6. A method for managing electronic payments with an electronic purse data carrier, comprising the steps of:

checking by a processor for each transaction if the age information of a payment unit stored on a storage device being part of the transaction has exceeded a predetermined transaction age threshold level, and restricting the use of a payment unit with an exceeded transaction age threshold level:

splitting by the processor a parent payment unit having a given non-minimum parent monetary value into a plurality of child payment units each having a child monetary value smaller than the parent value, the sum of child monetary values being the same as the parent monetary value, and transferring a respective age information from said parent unit to the plurality of child payment units, joining a plurality of single payment units having a given total monetary value into a joined payment unit having a corresponding same monetary value, and generating a resulting age information for said joined payment unit according to a predetermined rule, said step of transferring a respective age information further excluding said one or more payment units having a monetary value smaller than a predetermined value from inheriting age information, said step of transferring a respective age information further excluding said one or more payment units that have exceeded a predetermined change threshold age level from split or join process.

7. The method according to claim 6 , comprising the steps of using an age counter mechanism for checking the age information of a payment unit, the counter mechanism being implemented by encrypting a target number x, by successively applying, i a total of m-times, a private key to a source key and the respective application result, said source i key representing the unused age information, said target number x being the result of applying, a total of n-times, a public key to said source key, on each payment transaction applying said public key on said age information yielding a respective current age data, and checking for each transaction if the age information of a payment unit being part of the transaction corresponds to the target number x.

8. The method according to claim 7 , in which repetitive application of the public key to said source key, and the respective application results yields a monotone varying function with a transaction age threshold value corresponding to said target number x.

9. A computer program product stored on a computer usable medium comprising computer readable program means for causing a computer to manage electronic payments with an electronic purse data carrier, where the carrier stores age information corresponding to payment units stored thereon, the computer program product causing the computer to perform the steps of:

checking by a processor for each transaction if age information of a payment unit stored on a storage device being part of the transaction has exceeded a predetermined transaction age threshold level, and restricting use of a payment unit with an exceeded transaction age threshold level:

splitting by the processor a parent payment unit having a given non-minimum parent monetary value into a plurality of child payment units each having a child monetary value smaller than the parent value, the sum of child monetary values being the same as the parent monetary value, and transferring a respective age information from said parent unit to the plurality of child payment units, joining a plurality of single payment units having a given total monetary value into a joined payment unit having a corresponding same monetary value, and generating a resulting age information for said joined payment unit according to a predetermined rule, said step of transferring a respective age information further excluding said one or more payment units having a monetary value smaller than a predetermined value from inheriting age information, said step of transferring a respective age information further excluding said one or more payment units that have exceeded a predetermined change threshold age level from a split or join process.