Section: C.3.3 Processing on home network side
Content: The ECIES scheme shall be implemented such that for deconcealing a SUCI, the home network shall use the received ECC ephemeral public key of the UE and the private key of the home network. The processing on home network side shall be done according to the decryption operation defined in [29]. with the following changes to Section 3.8 and step 6 and 7 of Section 5.1.4. - generate keying data K of length enckeylen + icblen + mackeylen. - Parse the leftmost enckeylen octets of K as an encryption key EK, the middle icblen octets of K as an ICB, and the rightmost mackeylen octets of K as a MAC key MK. NOTE: Unlike the UE, the home network does not need to perform a fresh ephemeral key pair generation for each decryption. How often the home network generates new public/private key pair and how the public key is provisioned to the UE are out of the scope of this clause. The Figure C.3.3-1 illustrates the home network's steps. Figure C.3.3-1: Decryption based on ECIES at home network