1. 7/11/2006IETF-66 MSEC IPsec composite groups page 1 George Gross IdentAware ™ Multicast Security gmgross@IdentAware.com IETF-66, Montreal, Canada July 11 th 2006 Multicast IPsec Composite Cryptographic Groups

2. 7/11/2006IETF-66 MSEC IPsec composite groups page 2 Composite Cryptographic Groups Definition: The logical group formed from union of two or more sub-groups, each sub- group supporting different cryptographic properties (e.g. IPsec software version). Composite groups occur when large-scale groups contains multiple protocol versions or multiple partially interoperable vendors. –e.g. retiring 3-DES, migrating to AES –software bug fixes

3. 7/11/2006IETF-66 MSEC IPsec composite groups page 3 IPsec Subsystem Composite Group Requirements Multicast application is unaware of sub- groups, it only sends one packet to the composite group, not each sub-group. Must provide a mechanism where each data packet gets replicated for each sub-group, and treated with the respective sub-group’s IPsec cryptographic policy. IPsec policy per sub-group, set by its GCKS

4. 7/11/2006IETF-66 MSEC IPsec composite groups page 4 Motivation for Composite Groups Can not easily upgrade a large-scale group, no “flag day” is allowed Cryptographic algorithms age or break, need strategy to move to new ones –witness recent attacks on MD5, SHA-1 Parallel vendor-specific sub-groups support different feature sets, want best combination Straddle IPv4 and IPv6 sub-groups

5. 7/11/2006IETF-66 MSEC IPsec composite groups page 5 Sub-Group A A1 A4 Internet A2 A3 A0 A5 Sub-Group B B1 B4 B2 B3 B0 Group Speaker Host IPsec Subsystem B5 Transport mode multicast data security association Transport Mode IPsec

6. 7/11/2006IETF-66 MSEC IPsec composite groups page 6 Composite Cryptographic Group IPsec Transport Mode End-to-end security, no plain-text on wire Supports Native, BITS, and BITW architectural modes Requires IPsec subsystem replicate each data SA packet for each sub-group before applying its cryptographic algorithms –do not want the multicast application to be aware of the cryptographic sub-groups

7. 7/11/2006IETF-66 MSEC IPsec composite groups page 7 Sub-Group A A1 A4 Internet A2 A3 A0 A5 Sub-Group B B1 B4 B2 B3 B0 Group Speaker B5 Application data sent unencrypted across multicast LAN to security gateways IPsec Tunnel Endpoint IPsec Security Gateway IPsec Tunnel Endpoint IPsec Security Gateway multicast-capable LAN Tunnel Mode IPsec

8. 7/11/2006IETF-66 MSEC IPsec composite groups page 8 Composite Cryptographic Group IPsec Tunnel Mode Application multicasts its data to two or more IPsec security gateways, one gateway per sub-group. Advantage: simply bolt together as many gateways as there are sub-groups Drawback: Unencrypted data must transit a trusted network to reach the gateways

9. 7/11/2006IETF-66 MSEC IPsec composite groups page 9 Composite Groups Proposed for Experimental Track Request that draft-gross-ipsec-composite- group-00.txt become a MSEC WG item Publish as an IETF experimental RFC Revise and transition to a proposed standard RFC after: –additional operational experience –wider recognition by industry that this provides a solution that merits full standardization

10. 7/11/2006IETF-66 MSEC IPsec composite groups page 10 Background Reading draft-gross-msec-ipsec-composite-group- 00.txt draft-ietf-msec-ipsec-extensions-02.txt RFC4301 - IP security architecture