1. CCMP MIC Processing Paul Lambert September 2002
Paul Lambert, Airgo Networks, Inc.

2. September 2002
Overview
CCM Algorithm is based on AES and provides integrity (CBC mode) and confidentiality (CTR mode encryption)
CCMP is the IEEE TGi format and processing that defines how .11 MPDU fields are processed in CCM
Integrity processing is intended to be on all ‘invariant’ .11 fields
Paul Lambert, Airgo Networks, Inc.

3. Invariant Fields CCMP processing is once per MPDU
September 2002
Invariant Fields
CCMP processing is once per MPDU
Retransmitted MPDUs should NOT repeat cryptographic processing
Able to retransmit original MPDU
Integrity processing can NOT include fields that change on retransmission
Paul Lambert, Airgo Networks, Inc.

4. September 2002
Current CCMP Muting
CCMP ‘mutes’ fields so that hey are not part of the integrity processing.
Current (draft 2.3) muted CCMP fields:
Duration
Retry
Paul Lambert, Airgo Networks, Inc.

5. September 2002
Complete Analysis of fields for invariance of MIC calculation
Paul Lambert, Airgo Networks, Inc.

6. CCMP Muting Requirements
September 2002
CCMP Muting Requirements
The following CCMP fields must be muted:
Duration
Retry
More Data
Pwr Mgt
QoS-TXOP/QueueLength, FEC, Ack Policy
Paul Lambert, Airgo Networks, Inc.

7. September 2002
Motion
The CCMP integrity processing in the current Tgi draft shall be modified to mask to zero the ‘Pwr Mgt’, ‘More Data’ and ‘QC bits 4 to 15’ for purposes of the CBC integrity calculation.
Paul Lambert, Airgo Networks, Inc.