Secure wireless charging

1. At least one storage medium having instructions stored thereon for causing a system to:

cause a member computing node to:

establish a communication channel with a verifier computing node, the member computing node and the verifier computing node each coupled to a respective charging coil;

determine a group of devices approved for charging with the verifier computing node;

determine the member computing node is a member of the group of devices;

anonymously authenticate the member computing node to the verifier computing node;

in response to anonymously authenticating the member computing node to the verifier computing node, inductively charge the member computing node based on a magnetic field produced by the verifier computing node;

wherein: (a) the member computing node does not uniquely identify itself to the verifier computing node; (b) the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node signing a message with a private key and communicating the signed message to the verifier computing node; and (c) the private key and a plurality of other private keys all correspond to a public key coupled to the verifier computing node.

2. The at least one medium of claim 1 comprising instructions to:

determine the member computing node is not a member of the group of devices; and

communicate with an issuer computing node to become a member of the group of devices.

3. The at least one medium of claim 2 , wherein the private key is unknown to the issuer computing node before authenticating the member computing node to the verifier computing node.

4. The at least one medium of claim 1 comprising instructions to cause the member computing node to store the private key in secure out-of-band storage coupled to the member computing node.

5. The at least one medium of claim 1 , wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node.

6. The at least one medium of claim 5 wherein the membership proof is unlinkable.

7. The at least one medium of claim 1 , wherein the signed message is based on at least one of a list of corrupted private keys and a list of signatures.

8. The at least one medium of claim 7 comprising instructions to communicate a nonce between the verifier computing node and the member computing node;

wherein the signed message is based on the nonce.

9. The at least one medium of claim 8 ,

wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node;

wherein the zero-knowledge membership proof is based on the nonce.

10. The at least one medium of claim 1 , comprising instructions to communicate a membership credential between the member computing node and an issuer computing node, wherein signing the message with the private key comprises signing the message based on the membership credential.

11. The at least one medium of claim 10 , wherein the private key is based on the membership credential and an additional membership key.

12. The at least one medium of claim 11 , wherein the private key is based on a base value and a pseudonym and the base value and the pseudonym are included in a revocation list.

13. The at least one medium of claim 12 , wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node, the zero-knowledge membership proof being based on the base value and the pseudonym.

14. At least one storage medium having instructions stored thereon for causing a system to:

cause a member computing node to:

establish a communication channel with a verifier computing node, the member computing node and the verifier computing node each coupled to a respective charging coil;

determine a group of devices approved for charging with the verifier computing node;

determine the member computing node is a member of the group of devices;

anonymously authenticate the member computing node to the verifier computing node;

in response to anonymously authenticating the member computing node to the verifier computing node, inductively charge the member computing node based on a magnetic field produced by the verifier computing node;

wherein: (a) the member computing node does not uniquely identify itself to the verifier computing node, (b) the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node signing a message with a private key and communicating the signed message to the verifier computing node, and (c) the signed message is based on at least one of a list of corrupted private keys and a list of signatures.

15. The at least one medium of claim 14 comprising instructions to:

determine the member computing node is not a member of the group of devices; and

communicate with an issuer computing node to become a member of the group of devices;

wherein the private key and a plurality of other private keys all correspond to a public key coupled to the verifier computing node.

16. The at least one medium of claim 15 , wherein the private key is unknown to the issuer computing node before authenticating the member computing node to the verifier computing node.

17. The at least one medium of claim 14 comprising instructions to cause the member computing node to store the private key in secure out-of-band storage coupled to the member computing node;

wherein the private key and a plurality of other private keys all correspond to a public key coupled to the verifier computing node.

18. The at least one medium of claim 14 , wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node.

19. The at least one medium of claim 18 wherein the membership proof is unlinkable.

20. The at least one medium of claim 14 comprising instructions to communicate a nonce between the verifier computing node and the member computing node; wherein the signed message is based on the nonce.

21. The at least one medium of claim 20 ,

wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node;

wherein the zero-knowledge membership proof is based on the nonce.

22. The at least one medium of claim 14 , comprising instructions to communicate a membership credential between the member computing node and an issuer computing node, wherein signing the message with the private key comprises signing the message based on the membership credential.

23. The at least one medium of claim 22 , wherein the private key is based on the membership credential and an additional membership key.

24. The at least one medium of claim 23 , wherein the private key is based on a base value and a pseudonym and the base value and the pseudonym are included in a revocation list.

25. The at least one medium of claim 24 , wherein the anonymously authenticating the member computing node to the verifier computing node comprises the member computing node performing a zero-knowledge membership proof with the verifier computing node, the zero-knowledge membership proof being based on the base value and the pseudonym.