Method and apparatus of cipher communication for management frame using quality of service mechanism in wireless local area network system

A method of cipher communication for management frame performed by station in a wireless local area network system, the method comprising:

• obtaining a first pseudonoise code sequence (PN) for a plaintext Medium Access Control (MAC) protocol data unit (MPDU);
• constructing an additional authentication data (AAD) by using fields in a header of the plaintext MPDU;
• constructing a Nonce from the PN, an Address 2 field in the header of the plaintext MPDU and a Priority field in the header of the plaintext MPDU;
• generating a counter mode (CTR) with cipher block chaining (CBC)-MAC Protocol (CCMP) header including a second PN and a key identifier;
• generating a encrypted data and message integrity code (MIC) by using a temporal key, the AAD, and the Nonce;
• generating a encrypted MPDU by combining the header of the plaintext MPDU, the CCMP header, the encrypted data and the MIC;
• and
• transmitting the encrypted MPDU to a peer station;
• wherein the plaintext MPDU is a management frame including a sequence number field, the sequence number field including access category field indicating category of data included in the plaintext MPDU, and
• wherein the Nonce includes a priority field set to a value in the access category field of the sequence number field.

An apparatus for performing cipher communication of management frame in a wireless local area network system, the apparatus comprising a processor configured to:

• obtain a first pseudonoise code sequence (PN) for a plaintext Medium Access Control (MAC) protocol data unit (MPDU);
• construct an additional authentication data (AAD) by using fields in a header of the plaintext MPDU;
• construct a Nonce from the PN, an Address 2 field in the header of the plaintext MPDU and a Priority field in the header of the plaintext MPDU;
• generate a counter mode (CTR) with cipher block chaining (CBC)-MAC Protocol (CCMP) header including a second PN and a key identifier;
• generate an encrypted data and message integrity code (MIC) by using a temporal key, the AAD, and the Nonce;
• generate an encrypted MPDU by combining the header of the plaintext MPDU, the CCMP header, the encrypted data and the MIC;
• and
• transmit the encrypted MPDU to a peer station;
• wherein the plaintext MPDU is a management frame including a sequence number field, the sequence number field including access category field indicating category of data included in the plaintext MPDU, and
• wherein the Nonce includes a priority field set to a value in the access category field of the sequence number field.