The wrapping method for the variable-length key tokens will be AESKW as defined in ANSI X9.102.

The wrapping of the payload of a variable length key (*K) using an AES *MK is defined as follows:

e*MK(*K) = eAESKW*MK(P)

P = ICV || Pad Length || Hash Length || Hash options || Data Hash || *K || Padding

Where:

• ICV is the 6 byte constant 0xA6A6A6A6A6A6
• Pad length is the length of the Padding in bits
• Hash length is the length of the Data Hash in bytes
• Hash options is a 4-byte field
• Data Hash is the hash of the associated data block
• Padding is the number of bytes, 0x00, to make of the overall length of P a multiple of 16
• eAESKW means encryption using the AESKW method