Blockchain key storage on SIM devices

1. A method comprising:

accessing a Subscriber Identity Module (“SIM”) device, wherein the SIM device comprises:

an International Mobile Subscriber Identity (IMSI) and corresponding secret information that is specific to a user of the SIM device,

a hidden partition of the SIM device that stores a blockchain private key and a blockchain public key, and

a key applet configured to enforce credentialed access to the hidden partition of the SIM device;

obtaining the blockchain private key from the hidden partition of the SIM device by the key applet for digitally signing a record;

digitally signing the record with the blockchain private key; and

transmitting the digitally signed record for inclusion as a distributed ledger entry in a distributed ledger.

2. The method of claim 1 , the method further comprising:

authenticating a user device of the user of the SIM device.

3. The method of claim 2 , wherein authenticating the user device comprises obtaining an authentication associated with the authentication request from a home location register of a mobile carrier network.

4. The method of claim 2 , wherein authenticating the user device comprises obtaining an authentication associated with the authentication request from a home subscriber service of a mobile carrier network.

5. The method of claim 2 , the method further comprising:

obtaining, by an application executing on the user device, a user credential from the user; and

authenticating, by the application, the user credential, wherein accessing the SIM device is responsive to authenticating the user credential.

6. The method of claim 2 , wherein authenticating the user device is via an authentication proxy to a mobile network operator (MNO) of a mobile carrier network.

7. The method of claim 2 , the method further comprising:

obtaining, by an application executing on the user device, a user credential from the user; and

authenticating, by the application, the user credential by executing an authentication, authorization, and accounting function to authenticate the user credential.

8. The method of claim 1 , wherein the blockchain private key is encrypted while stored in the hidden partition of the SIM device.

9. The method of claim 1 , wherein the credentialed access to the hidden partition of the SIM device requires an encrypted passcode encoded in the key applet.

10. A user device comprising:

a Subscriber Identity Module (“SIM”) device that comprises:

an International Mobile Subscriber Identity (IMSI) and corresponding secret information that is specific to a user of the SIM device,

a hidden partition of the SIM device that stores a blockchain private key and a blockchain public key, and

a key applet configured to enforce credentialed access to the hidden partition of the SIM device;

one or more physical processors;

wherein the key applet executing on either the SIM device or the one or more processors is configured to:

receive an authentication request associated with joining a mobile carrier network,

confirm the authentication request to join the mobile carrier network,

access the hidden partition of the SIM device based on confirming the authentication request, and

obtain the blockchain private key from the SIM device.

11. The user device of claim 10 , wherein the key applet is further configured to:

authenticate the user device of the user of the SIM device.

12. The user device of claim 11 , wherein the authentication is from a home location register of the mobile carrier network.

13. The user device of claim 11 , wherein the authentication is from a home subscriber service of the mobile carrier network.

14. The user device of claim 11 , wherein the authentication is a multi-factor authentication that includes supplying the key applet with a valid passcode.

15. The user device of claim 11 , wherein authenticating the user device is via an authentication proxy to a mobile network operator (MNO) of the mobile carrier network.

16. A Subscriber Identity Module (“SIM”) device, comprising:

an International Mobile Subscriber Identity (IMSI) and corresponding secret information that is specific to a user of the SIM device;

a hidden partition of the SIM device that stores a blockchain private key and a blockchain public key;

a storage that stores subscriber authentication data for authentication to cellular network via a challenge-response; and

a key applet that is configured to enforce credentialed access to the hidden partition of the SIM device by:

receive a request to access the blockchain private key, the request including an authentication credential;

authenticate the authentication credential;

access the blockchain private key from the hidden partition; and

provide the blockchain provide key responsive to the request.

17. The SIM device of claim 16 , wherein the key applet is further configured to:

verify that the subscriber authentication data has been authenticated by the cellular network prior to the access and provision of the blockchain private key.

18. The SIM device of claim 17 , wherein to verify that the subscriber authentication data has been authenticated by the cellular network, the key applet is further configured to:

obtain an authentication from a home location register of the cellular network.

19. The SIM device of claim 17 , wherein to verify that the subscriber authentication data has been authenticated by the cellular network, the key applet is further configured to:

obtain an authentication from a home subscriber service of the cellular network infrastructure.