1. A DRM Security Architecture for Home Network
Bogdan C. Popescu, Frank L.A.J Kamperman
Fourth Annual ACIS International Conference on Computer and Information Science (ICIS'05) – Volume 00 ICIS '05

2. Compliant Device Make by CE Manufacturer.
Given a public/private key pair
Private key stored in tamper-resistant memory
Public key certified by manufacturer by mean of a device certificate.
Identified by a unique Global Device ID( GDI )
Include in device certificate.
Manufacturer-prefix + device serial number
Local Device ID( LDI )
No cryptographic hardware accelerator

3. Authorized Domain Framework
Distribute revocation information
Licensing
Authority
Content
Provider
Content
Provider
License
Manufacture
Distribute content
Content
Manager CE
Manufacturer
Authorized Domain
Certify
device
Content
Manager
Register
device
Exchange content
Domain
Manager
Compliant
Device
Compliant
Device CE
Manufacturer
Compliant
Device
Compliant
Device
Certify
device

4. Authorized Domain Creation
Generate a master device key list
Size is equal to maximum number of device allowed
Generate domain ID
As concatenation of the manager’s GDI and ever-increasing domain version number
At manufacture, domain version number is zero.
If AD manager reset, domain version number is incremented.

5. Notation Description entity E’s public key certificate
Symbol
Description
certE
entity E’s public key certificate
YE/XE
entity E’s public / private key pair NE
a random nonce generated by entity E
{data}K
encrypted with the symmetric / asymmetric key K
[data]K
transmitted over a secure channel protected by a symmetric key K 5

6. Device Registration certA, { NA, GDIM } XA
Domain manager
certM , { NM, GDIA , NA , { kS }YA }xM
Compliant device A
certA, { NM, GDIM } XA
[ LDIA, KA , credentialsSetA ] ks

7. Device Authorization LDIA , NA LDIB, NB, authenticationTicketBA
Compliant device A
Compliant device B
{ NB}K , authenticationTicketAB
{ NA}K
K = SHA-1(KAB, KBA, NA, NB)
Authentication credential set
authentication key that is symmetric key
Share between device with in same AD domain.
authentication ticket associate with authentication key

8. Local Revocation List Generate by AD Manager
Consists of the GDIs of domain device
Revoked
Removed from domain
Revoked device cannot receive new data digital content, so that eventually become useless.

9. Device removal Voluntary leave Damaged / Stolen Devices
Domain manager to identify the device to be removed
Device Revocation
Compliant are revoke by the licensing organization by having their GDLs listed on the global revocation list.
Distributed by content providers together with the data content items.
Content manager also report the identify of the domain manager to the providers.
content manager attempt to connect to domain manager
If AD Manager is reachable, Forward it the GDRL, process and return a Local Revocation List ( LRL ),
If AD manager is not reachable. The content manager keep the original GDRL attached to the data content

10. Key Update
If too many device are removed from the domain, the domain manager may run out of master key to assign to new device
Terminate domain and re-create a new master key list.
Not user-friendly
Re-use the LDIs of removed device and assign to new device

11. Key Update LDIB , NB LDIC, NC, authenticationTicketCA
Compliant device B
Assigned device A
that has been removal
Compliant device C
{ KCB,authenticationTicketCB}KC
, authenticationTicketBC
{ NB}K , authenticationTicketCB
{ NC}K
K = SHA-1(KBC, KBC, NC, NB)