# US 2010/0166183 A1 · Optimizing security bits in a media access control (mac) header

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- Number: US 2010/0166183 A1
- Document ID: US20100166183A1
- Status: Published application
- Kind: A1
- Application number: 12/347,872
- Filed: 2008-12-31
- Published: 2010-07-01
- Earliest claimed: 2008-12-31
- Assignees: Intel Corporation
- Inventors: David Johnston; Muthu Vankatachalam
- Web page: https://patentgrep.com/patent/US20100166183A1

## CPC

- H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying}
- H04L 69/22: Parsing or analysis of headers
- H04W 12/033: of the user plane, e.g. user's traffic
- H04W 12/037: of the control plane, e.g. signalling traffic
- H04L 2209/80: Wireless
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method of retrieving security information in a media access control (MAC) header by a wireless station may include receiving a data unit, such as a protocol data unit (PDU), from a remote wireless station. The PDU may include the MAC header. The method may also include reading two encryption key sequence (EKS) bits in the MAC header that denote both whether the data unit is encrypted and a position in an encryption key sequence for the data unit.

## Claims

### Claim 1

A method of providing security information in a media access control (MAC) header by a wireless station, comprising:
generating a data unit including the MAC header, the MAC header including:
two bits that denote both whether the data unit is encrypted and an encryption key sequence for the data unit; and
transmitting the data unit to a remote wireless station.

### Claim 2 (depends on 1)

The method of claim 1, wherein the two bits are encryption key sequence (EKS) bits located in a predefined location within the MAC header.

### Claim 3 (depends on 1)

The method of claim 1, wherein the MAC header does not include a separate encryption (EC) bit whose state denotes whether the data unit is encrypted.

### Claim 4 (depends on 1)

The method of claim 1, wherein one of four possible states of the two bits indicates that the data unit is unencrypted.

### Claim 5 (depends on 1)

The method of claim 1, wherein three of four possible states of the two bits denote one of three positions in an encryption key sequence.

### Claim 6 (depends on 1)

The method of claim 1, wherein the generating includes:
encrypting at least a portion of the data unit with a current encryption key or with a new encryption key in accordance with a state of the two bits before the transmitting.

### Claim 7

A method of retrieving security information in a media access control (MAC) header by a wireless station, comprising:
receiving a data unit including the MAC header from a remote wireless station; and
reading two encryption key sequence (EKS) bits in the MAC header that denote both whether the data unit is encrypted and a position in an encryption key sequence for the data unit.

### Claim 8 (depends on 7)

The method of claim 7, wherein the data unit is a MAC protocol data unit (MPDU).

### Claim 9 (depends on 7)

The method of claim 7, wherein the MAC header does not include a separate encryption (EC) bit whose state denotes whether the data unit is encrypted.

### Claim 10 (depends on 7)

The method of claim 7, wherein one of four possible states of the two EKS bits indicates that the data unit is unencrypted; and
reading a payload of the data unit as plaintext when the two EKS bits have the one of the four possible states.

### Claim 11 (depends on 7)

The method of claim 7, wherein three of four possible states of the two EKS bits denote one of three positions in an encryption key sequence.

### Claim 12 (depends on 7)

The method of claim 7, further including:
decrypting the data unit with a current encryption key or with a new encryption key in accordance with a state of the EKS two bits.

### Claim 13

A wireless station, comprising:
a media access control (MAC) module arranged to generate or parse a protocol data unit (PDU) including a MAC header:
that includes two encryption key sequence (EKS) bits that denote both whether the PDU is encrypted and an encryption key sequence for the PDU, and
that does not include an encryption (EC) bit that is separate from the EKS bits; and
a physical layer (PHY) module arranged to send the PDU to the MAC module or to receive the PDU from the MAC module.

### Claim 14 (depends on 13)

The wireless station of claim 13, wherein the MAC module is further arranged to encrypt or decrypt the PDU in accordance with a state of the two EKS bits.

### Claim 15 (depends on 13)

The wireless station of claim 13, wherein the MAC module is further arranged to read unencrypted data directly from a payload of the PDU in accordance with a state of the two EKS bits.

### Claim 16 (depends on 13)

The wireless station of claim 13, further comprising:
an antenna coupled to the PHY module to wirelessly transmit or receive a signal including information in the PDU.

### Claim 17 (depends on 13)

The wireless station of claim 13, wherein one of four possible states of the two EKS bits indicates that the PDU is unencrypted, and
wherein another three of the four possible states of the two EKS bits denote one of three positions in an encryption key sequence.