IEEE Std 1609.2b pdf free download
IEEE Std 1609.2b pdf free download.Wireless Access in Vehicular Environments- Security Services for Applications and Management Messages Amendment 2: PDU Functional Types and Encryption Key Management.
if the key was not “ephemeral”. i.e., generated within the SDS at the time of data encryption, it is referred to as “static”.
Following data encryption, the SDS creates Recipientinfos which allow the intended recipients to access the data encryption key. Each different key encryption key I will in general correspond to a different intended recipient of the encrypted PDIJ.
The recipients are provided intormation about the data encryption key as follows:
— If the invoking SDEE provided one or more recipient keys, the SDS encrypts the key k with each of those key keys to produce a series of encrypted keys {ekil, with each ek, an encryption of k with key encryption key i. This process is specified in 5.3.4.3. For each key encryption key i, the SDS creates a Recipientinfo structure containing the encrypted key eL. of the ty determined by the type of the recipient’s encryption key as specified in 6.3.37. This enables the recipients in possession of the corresponding decryption key to recover the data encryption key.
— If the invoking SDEE requested a direct indication of the data encryption key, the SDS creates a single Recipientinfo structure of type PreSharedKeyRecipientlnfo identifying the data encryption key. This enables recipients who already possess the data encryption key to identify that it is the key to be used to decrypt the encrypted data.
— The SDS then encodes all the Recipientinfos into a SeguenceOfRecipientinfo, encodes the SeguenceOtRecipientlnfo and the SymmetricCiphertexi into an EncryptedData, and encapsulates the EncryptedData in an Ieee l6O9Dot2Data.
This approach allows an EncryptedData to be created for recipients that already know the data encryption key. for recipients that do not already know the data encryption key. or for a combination of the two types of recipients.
In the Sec-EncryptedData.request primitive of 9.3.11.1, the SDEE indicates to the SDS whether to use an ephemeral or static data encryption key by providing or not providing the 1)ata Encryption Key Type parameter. If the SDEE requested an ephemeral data encryption key, the SDS may return a cryptomaterial handle (see 4.3.3 and 9.2.2) for that data encryption key in the corresponding Sec-EncryptedData.confirrn primitive to enable that data encryption key to be reused ifdesired.
In the Sec-EncryptedDataDecrvption.confirm primitive of 9.3.13.2, the SDS may provide a Crvptoimterial Handle for the data encryption key in the Data Encnpion Key CMH parameter. This enables the S[)FE that receives this primitive to store the CMII for later use.
5.3.4.2 Data encryption
Data encryption is perfomied as follows:
The plaintext P has the form of a valid encoded Ieeel6O9Dot2Data structure.
A symmetric data encryption key k for an approved symmetric algorithm as specified in 5.3.8 is available as described in 5.3.4.1.
— P is encrypted with k to obtain a ciphertext C. If the approved symmetric algorithm uses a notice, that nonce is generated freshly and at random for each new plaintext.
— The ciphertext C is encoded as a SymmetricCiphertext.IEEE Std 1609.2b pdf download.
