Reliable storage medium access control method and device
AssigneeIntrinsic Id B.V.
InventorJohan Paul Maria Gerard Linnartz
Life of this patent
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Abstract
A method of and device for granting access to content on a storage medium, including obtaining cryptographic data from a property, such as a wobble, of the storage medium, reading helper data from the storage medium, and granting the access based on an application of a delta-contracting function to the cryptographic data and the helper data. The delta-contracting function allows the choice of an appropriate value of the helper data, such that any value of the cryptographic data which sufficiently resembles the original primary input value leads to the same output value. Substantially different values of the cryptographic data lead to different values of the output.
Claims18
A method of calculating reliable bits from cryptographic data;
- the method comprising acts of:
- obtaining the cryptographic data from a property of a non-transitory medium,
- reading helper data from a storage medium, and
- calculating the reliable bits based on an application of a delta-contracting function to the cryptographic data and the helper data, wherein the helper data defines ranges of values for the cryptographic data and the delta-contracting function defines a corresponding output value for each range of values for the cryptographic data so that the helper data can be made to adapt the cryptographic data for a particular medium in tolerating small deviations in the obtained cryptographic data.
A device arranged for calculating reliable bits from cryptographic data, comprising first reading means for obtaining the cryptographic data from variations in a physical property of a medium, second reading means for reading helper data from a storage medium, and calculating means for calculating the reliable bits based on an application of a delta-contracting function to the cryptographic data and the helper data, wherein the helper data defines ranges of values for the cryptographic data and the delta-contracting function defines a corresponding output value for each range of values for the cryptographic data so that the helper data can be made to adapt the cryptographic data for a particular medium in tolerating small deviations in the obtained cryptographic data.
A non-transitory computer-readable medium having a computer program product recorded thereon, said computer program product being arranged to cause a processor to perform acts of:
- obtaining cryptographic data from a property of a medium,
- reading helper data from a storage medium, and
- calculating reliable bits based on an application of a delta-contracting function to the cryptographic data and the helper data, wherein the helper data defines ranges of values for the cryptographic data and the delta-contracting function defines a corresponding output value for each range of values for the cryptographic data so that the helper data can be made to adapt the cryptographic data for a particular medium in tolerating small deviations in the obtained cryptographic data.
Dependencies are inferred from the claim text.