Authenticated checkin via passive NFC

1. A method, comprising:

initializing a digital check-in chain for a venue;

expanding, electronically by a processor, the check-in chain with a plurality of check-in entries that each correspond to a visit to the venue by a respective user, wherein each check-in entry on the check-in chain is generated in response to one or more preceding check-in entries on the check-in chain;

detecting fraudulent check-in entries in response to a split in the check-in chain; and

removing the fraudulent check-in entries from the check-in chain.

2. The method of claim 1 , wherein the initializing the digital check-in chain comprises generating a check-in seed that contains information about the venue.

3. The method of claim 1 , wherein each check-in entry contains a cryptographic signature of its corresponding user.

4. The method of claim 3 , wherein each cryptographic signature is generated as a function of every other existing cryptographic signature on the check-in chain.

5. The method of claim 3 , wherein each check-in entry further contains a unique user identification.

6. The method of claim 1 , wherein the expanding the check-in chain comprises:

receiving a check-in request from a user, the check-in request containing information that is signed with a private key associated with the user; and

validating the check-in request using a public key associated with the user.

7. The method of claim 1 , wherein at least some of the check-in entries correspond to visits to the venue by the same user.

8. The method of claim 1 , wherein the detecting fraudulent check-in entries comprises:

receiving multiple check-in requests corresponding to different users, wherein all the check-in requests depend from the same previous check-in entry on the check-in chain, thereby splitting the check-in chain into multiple branches;

monitoring subsequent check-in activities for each branch; and

determining which branch is fraudulent based on the subsequent check-in activities.

9. The method of claim 1 , wherein each check-in entry is generated using a Near Field Communication (NFC) technology.

10. An apparatus comprising a non-transitory, tangible computer readable storage medium storing a computer program, wherein the computer program contains instructions that when executed, perform:

initializing a digital check-in chain for a venue;

expanding, electronically by a processor, the check-in chain with a plurality of check-in entries that each correspond to a visit to the venue by a respective user, wherein each check-in entry on the check-in chain is generated in response to one or more preceding check-in entries on the check-in chain;

detecting fraudulent check-in entries in response to a split in the check-in chain; and

removing the fraudulent check-in entries from the check-in chain.

11. The apparatus of claim 10 , wherein the instructions for initializing the digital check-in chain comprise instructions for generating a check-in seed that contains information about the venue.

12. The apparatus of claim 10 , wherein each check-in entry contains a cryptographic signature of its corresponding user.

13. The apparatus of claim 12 , wherein each cryptographic signature is generated as a function of every other existing cryptographic signature on the check-in chain.

14. The apparatus of claim 12 , wherein each check-in entry further contains a unique user identification.

15. The apparatus of claim 10 , wherein the instructions for expanding the check-in chain comprise instructions for:

receiving a check-in request from a user, the check-in request containing information that is signed with a private key associated with the user; and

validating the check-in request using a public key associated with the user.

16. The apparatus of claim 10 , wherein at least some of the check-in entries correspond to visits to the venue by the same user.

17. The apparatus of claim 10 , wherein the instructions for detecting fraudulent check-in entries comprise instructions for:

receiving multiple check-in requests corresponding to different users, wherein all the check-in requests depend from the same previous check-in entry on the check-in chain, thereby splitting the check-in chain into multiple branches;

monitoring subsequent check-in activities for each branch; and

determining which branch is fraudulent based on the subsequent check-in activities.

18. The apparatus of claim 10 , wherein each check-in entry is generated using a Near Field Communication (NFC) technology.

19. A method, comprising:

providing a check-in seed for a venue;

receiving a first check-in entry, the first check-in entry being a function of the check-in seed;

verifying, electronically by a processor, the first check-in entry;

forming a check-in chain by appending the first check-in entry after the check-in seed if the first check-in entry is successfully verified;

receiving a second check-in entry, the second check-in entry being a function of the check-in seed and the first check-in entry;

verifying, electronically by the processor, the second check-in entry; and

expanding the check-in chain by appending the second check-in entry after the first check-in entry if the second check-in entry is successfully verified.

20. The method of claim 19 , wherein:

the first check-in entry and the second check-in entry contain a first cryptographic signature and a second cryptographic signature, respectively; and

the verifying the first check-in entry and the verifying the second check-in entry are performed by verifying the first cryptographic signature and verifying the second cryptographic signature, respectively.

21. The method of claim 20 , wherein the first cryptographic signature and the second cryptographic signature are generated with a first private key and a second private key, respectively.

22. The method of claim 20 , wherein the verifying the first check-in entry and the verifying the second check-in entry are performed at least in part by verifying the first cryptographic signature with a first public key and verifying the second cryptographic signature with a second public key, respectively.

23. The method of claim 19 , further comprising: continuously expanding the chain by verifying additional check-in entries and appending the additional check-in entries to the check-in chain, wherein each check-in entry on the check-in chain is dependent on previous check-in entries on the check-in chain.

24. The method of claim 23 , further comprising: identifying fraudulent check-ins by detecting a break in the check-in chain.

25. The method of claim 23 , further comprising: resetting the check-in chain after the check-in chain has reached a predetermined number of check-in entries.

26. The method of claim 19 , wherein the first check-in entry and the second check-in entry are each generated using a device equipped with a Near Field Communications (NFC) technology.