1. ROLL RPL Security IETF 77 status
draft-sdt-roll-rpl-security
Kris Pister,
Security Design Team
Slide #1
IETF 77 – Roll WG – March 2010

2. Status Drafts: Related: draft-tsao-roll-security-framework-02
draft-sdt-roll-rpl-security-00
draft-struik-roll-rpl-security-design-00
Related:
Draft-oflynn-6lowapp-bootstrapping-00
Slide #2
IETF 77 – Roll WG – March 2010

3. Scope Routing Security Later or out of scope
Provide mechanisms to protect RPL {DIS, DIO, DAO, “flow label”} from outsider attack
Later or out of scope
Policy
Key distribution
Insider attack
Relationship to other security (L2, L4, …)

4. Range of RPL Applications
Toys
No security ok?
Consumer/commercial
Perception of risk varies widely
Enterprise-critical
Appropriate paranoia
Need to satisfy “enterprise-critical” without driving away “consumer/commercial”

5. “Protect” DIO, DIS, DAO, flow label
Packets are not modified during transport
Participant IDs are authentic
Retransmissions are detected
Content optionally encrypted

6. Mechanisms AES128 CCM* Where to draw the “MUST support” line?
1) no security
2) shared instance-wide key
3) shared pair-wise keys
4) digital signatures

7. Authentication Proposed 4 levels No authentication
Pre-configured, instance-wide join key
Pre-configured join key(s) with access control list at LBR
Public key certificate

8. Implementation
Still several options for where to put security material
DIS, DIO, DAO
Sub-option
“security-field-present” bit
Flow label
Hop-by-hop option (hui-6man-rpl-option)
TLV or “security present” bit
| Option Type | Opt Data Len |
| (sub-TLVs) |

9. Example Packet format (1)
March 22, 2010
Example Packet format (1)
RPL Control Message
Security bit indicates whether packet is secured, and auxiliary security header is present.
octets: 1 1 2
variable
Type
Code
Checksum
Message Body
RPL Type
Description
0x00
DODAG Information Solicitation
0x01
DODAG Information Object
0x02
Destination Advertisement Object
0x03
Reserved
bits: 0-2 3
4-7
RPL Type
Security
Reserved
Code field
Slide 9
Page 9
<author>, <company>

10. Example packet format (2)
March 22, 2010
Example packet format (2)
Auxiliary Security Header (cont’d)
- Only present if security field set
Security control field: indication as to which security services enabled
Granularity: specific combinations of data confidentiality & data integrity
Counter field: indication of non-repeating value used in crypto construct
Compression option provided (if devices have clock on board and timeliness possible)
Key Identifier field: indication as to which key was used to secure packet
Granularity: peer-to-peer key, group key, network-wide key, {signature key}
MIC: message integrity code
octets: 1
1/4
0/1/9
Security Control
Counter
Key Identifier
Auxiliary Security Header
1/2/4?
MIC
Slide 10
Page 10
<author>, <company>

11. Summary
Can provide simple, standard, lightweight mechanisms to protect routing information
Min 2B? per data packet (flow label)
Typ 5B? per DIS/DIO/DAO
Still lots of detail work to do
Open issues
Insider attack: LBR consistency checking?
Error/alarm messages