Secure management of a master encryption key in a split-key based distributed computing environment

Patent metadata

Field	Value
Publication number	US-9954680-B1
Application number	US-201514974454-A
Country	US
Kind code	B1
Filing date	Dec 18, 2015
Priority date	Dec 18, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A master encryption key is split at a key splitting server such that three key shares are required to reconstruct it, and is then destroyed. The key shares are distributed such that an encrypted remote management server key share is stored at a remote management server, an encrypted managed device key share is stored at a managed device, and a key splitting server key share is stored on the key splitting server. Incoming communications to the key splitting server from managed devices are prevented, and outgoing communications from the key splitting server are only allowed to managed devices. The managed device obtains the master encryption key at startup by sending its managed device key share to the remote management server, which sends the managed device key share and the remote management server key share to the key splitting server. The key splitting server reconstructs the master encryption key, encrypts it using a public key of the managed device, and sends it to the managed device.

First claim

What is claimed is:

1. A method of protecting a master encryption key in a distributed computing system, comprising:
generating, by a key splitting server, a master encryption key;
splitting the master encryption key, by the key splitting server, into multiple key shares using a polynomial-based secret sharing technique, wherein the splitting is performed such that at least three different ones of the key shares must be combined in order to reconstruct the master encryption key;
distributing individual ones of the key shares, by the key splitting server, to different components in the distributed computing system by
generating a remote management key share by encrypting a first one of the key shares using a key encryption key stored on the key splitting server and sending the remote management key share from the key splitting server to a remote management server to be stored on the remote management server,
generating a managed device key share by encrypting a second one of the key shares using the key encryption key and sending the device key share to at least one managed device to be stored on the managed device, and
generating a key splitting server key share by storing a third one of the key shares on the key splitting server;

destroying, by the key splitting server, the master encryption key; and
performing a start-up operation on the managed device at least in part by
receiving a reconstructed master encryption key by the managed device,
using the reconstructed master encryption key by the managed device to complete the start-up operation at least in part by encrypting a protected key store located within the managed device using the reconstructed master encryption key, and
after using the reconstructed master encryption key by the managed device to complete the start-up operation, destroying all local copies of the reconstructed master encryption key on the managed device.

2. The method of claim 1 , wherein encrypting the first one of the key shares to generate the remote management server key share includes performing a key wrapping operation on the first key share using the key encryption key; and
wherein encrypting the second one of the key shares to generate the managed device key share includes performing a key wrapping operation on the second key share using the key encryption key.

3. The method of claim 2 , wherein the key encryption key comprises the key splitting server key share;
wherein performing the key wrapping operation on the first key share includes wrapping the first key share using the key splitting server key share; and
wherein performing the key wrapping operation on the second key share includes wrapping the second key share using the key splitting server key share.

4. The method of claim 2 , wherein the key encryption key comprises a public key of a public/private key pair uniquely assigned to the key splitting server;
wherein performing the key wrapping operation on the first key share includes wrapping the first key share using the public key of the public/private key pair uniquely assigned to the key splitting server; and
wherein performing the key wrapping operation on the second key share includes wrapping the second key share using the public key of the public/private key pair uniquely assigned to the key splitting server.

5. The method of claim 2 , wherein generating the key splitting server key share includes performing a key wrapping operation on the third one of the key shares, before storing the key splitting server key on the key splitting server, by wrapping the third one of the key shares using the public key of the public/private key pair uniquely assigned to the key splitting server.

6. The method of claim 2 , further comprising configuring at least one component of the distributed computing system to allow outgoing communications from the key splitting server to the managed device and to prevent incoming communications to the key splitting server from the managed device.

7. The method of claim 6 , wherein configuring at least one component of the distributed computing system to allow outgoing communications from the key splitting server to the managed device and to prevent incoming communications to the key splitting server from the managed device comprises configuring the key splitting server to allow outgoing communications from the key splitting server to the managed device and to prevent incoming communications to the key splitting server from the managed device.

8. The method of claim 6 , wherein configuring at least one component of the distributed computing system to allow outgoing communications from the key splitting server to the managed device and to prevent incoming communications to the key splitting server from the managed device comprises configuring a network firewall to allow outgoing communications from the key splitting server to the managed device and to prevent incoming communications to the key splitting server from the managed device.

9. The method of claim 7 , wherein configuring the key splitting server to allow outgoing communications to the managed device and to prevent incoming communications from the managed device to the key splitting server comprises:
receiving a list of managed devices, by the key splitting server from the remote management server, wherein the list of managed devices includes network addressing information for the managed device; and
wherein the key splitting server allows outgoing communications from the key splitting server to the managed device and prevents incoming communications to the key splitting server from the managed device in response to the network addressing information for the managed device included in the list of managed devices.

10. The method of claim 6 ,
wherein performing the start-up operation on the managed device further includes:
receiving, by the key splitting server from the remote management server, a request to reconstruct the master encryption key, wherein the request to reconstruct the master encryption key includes i) the remote management server key share, and ii) the managed device key share, wherein the managed device key share was received by the remote management server from the managed device,
decrypting, by the key splitting server, the remote management server key share and the managed device key share,
generating, by the key splitting server using the decrypted remote management server key share, the decrypted managed device key share and the key splitting server key share, a reconstructed master encryption key, and
sending the reconstructed master encryption key from the key splitting server to the managed device.

11. The method of claim 10 , wherein the key encryption key comprises the key splitting server key share;
wherein decrypting the remote management server key share comprises decrypting the remote management key share using the key splitting server key share; and
wherein decrypting the managed device key share comprises decrypting the remote management key share using the key splitting server key share.

12. The method of claim 10 , wherein the key encryption key comprises the public key of the public/private key pair uniquely assigned to the key splitting server;
wherein decrypting the remote management server key share comprises decrypting the remote management server key share using the private key of the public/private key pair uniquely assigned to the key splitting server; and
wherein decrypting the managed device key share comprises decrypting the managed device key share using the private key of the public/private key pair uniquely assigned to the key splitting server.

13. T

Assignees

• Emc Corp
• Emc Ip Holding Co Llc

Inventors

• Machani Salah
• Friedman Lawrence N

Classifications

• H04L9/0822

  using key encryption key · CPC title

• H04L9/0825

  using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates · CPC title

• H04L9/0861

  Generation of secret information including derivation or calculation of cryptographic keys or passwords · CPC title

• H04L9/085 Primary

  Secret sharing or secret splitting, e.g. threshold schemes · CPC title

• H04L9/0894

  Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage · CPC title