Device-to-device communication security with authentication certificates

1. An apparatus comprising at least one processor and at least one memory including computer program code for one or more programs, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

transmit, to a first network node, a request for a certificate comprising at least one identifier associated with the apparatus, the request comprising a request identifier with a security association established between the apparatus and another apparatus in a device-to-device communication network;

receive, from the first network node, the certificate;

forward the certificate to the other apparatus;

receive, from the other apparatus, another certificate, the other certificate comprising at least one other identifier associated with the other apparatus;

authenticate the other apparatus based on the other certificate; and

enable, in response to the authentication, communication with the other apparatus.

2. The apparatus of claim 1 , wherein the apparatus is caused to at least:

discover the other apparatus; and

establish between the apparatus and the other apparatus the security association.

3. The apparatus of claim 2 , wherein establishment between the apparatus and the other apparatus of the security association comprises an establishment of a cryptographic pipe between the apparatus and the other apparatus.

4. The apparatus of claim 3 , wherein to forward the certificate to the other apparatus, the apparatus is caused to at least:

encrypt the certificate with the cryptographic pipe key; and

transmit the encrypted certificate to the other apparatus.

5. The apparatus of claim 3 , wherein receipt of the other certificate from the other apparatus comprises:

receipt of an encrypted certificate from the other apparatus; and

generation of the other certificate from the encrypted certificate by decrypting the encrypted certificated based on a key from the cryptographic pipe.

6. The apparatus of claim 1 , wherein authentication of the other apparatus based on the other certificate comprises a determination as to whether the at least one other identifier associated with the other apparatus matches a value stored within the apparatus.

7. The apparatus of claim 1 , wherein the certificate comprising at least one identifier associated with the apparatus comprises at least one of:

an asymmetric public key;

a public identifier derived from a Diffie-Hellman group element originating from the apparatus;

an identifier based on the established security association between the apparatus and the other apparatus;

a location of an access point to which the apparatus is associated with;

a phone number associated with the apparatus;

an International Mobile Subscriber Identity associated with the apparatus; and

a Temporary Mobile Subscriber Identity associated with the apparatus.

8. The apparatus of claim 1 , wherein the other certificate comprising at least one other identifier associated with the other apparatus comprises at least one of:

an asymmetric public key;

a public identifier derived from a Diffie-Hellman group element originating from the other apparatus;

an identifier based on the established security association between the apparatus and the other apparatus;

a location of an access point to which the other apparatus is associated with;

a phone number associated with the other apparatus;

an International Mobile Subscriber Identity associated with the other apparatus; and

a Temporary Mobile Subscriber Identity associated with the other apparatus.

9. The apparatus of claim 1 , wherein the other certificate is provided by a second network node.

10. An apparatus comprising at least one processor and at least one memory including computer program code for one or more programs, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

receive a request from a first apparatus for a certificate comprising at least one identifier associated with the first apparatus, the request comprising a request identifier with a security association established between the first apparatus and a second apparatus in a device-to-device communication network;

generate the certificate comprising the at least one identifier associated with the first apparatus; and

transmit the certificate comprising the at least one identifier associated with the first apparatus, wherein the certificate is configured to be exchanged between the first apparatus and the second apparatus to authenticate the first apparatus at the second apparatus to enable communication between the first apparatus and the second apparatus.

11. The apparatus of claim 10 , wherein generation of the certificate comprising the at least one identifier associated with the first apparatus comprises determination of at least one of:

an asymmetric public key associated with the first apparatus;

a Diffie-Hellman group element originating from the first apparatus;

a location of an access point to which the first apparatus is associated with;

a phone number associated with the first apparatus;

an International Mobile Subscriber Identity associated with the first apparatus; and

a Temporary Mobile Subscriber Identity associated with the first apparatus.

12. The apparatus of claim 10 , wherein receipt of a request from the first apparatus for the certificate comprising at least one identifier associated with the first apparatus comprises receipt of the established security association between the first apparatus and the second apparatus, and wherein generation of the certificate comprising the at least one identifier associated with the first apparatus comprises generation of an identifier based on the established security association between the first apparatus and the second apparatus.

13. An apparatus comprising:

a requester configured to request, from a first network node, a certificate comprising at least one identifier associated with the apparatus, the request comprising a request identifier with a security association established between the apparatus and another apparatus in a device-to-device communication network;

a first receiver configured to receive the certificate from the first network node;

a forwarder configured to forward the certificate to the other apparatus;

a second receiver configured to receive another certificate from the other apparatus, the other certificate comprising at least one other identifier associated with the other apparatus;

an authenticator configured to authenticate the other apparatus based on the other certificate; and

an enabler configured to enable, in response to the authentication, communication with the other apparatus.