George Gross IdentAware ™ Multicast Security gmgross@IdentAware IETF-66, Montreal, Canada

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

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 IETF-66 MSEC IPsec composite groups page 2

3. IPsec SubsystemComposite 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 IETF-66 MSEC IPsec composite groups page 3

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 IETF-66 MSEC IPsec composite groups page 4

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

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 IETF-66 MSEC IPsec composite groups page 6

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

8. Composite Cryptographic GroupIPsec 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 IETF-66 MSEC IPsec composite groups page 8

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 IETF-66 MSEC IPsec composite groups page 9

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