Section: C.3.2 Processing on UE side
Content: The ECIES scheme shall be implemented such that for computing a fresh SUCI, the UE shall use the provisioned public key of the home network and freshly generated ECC (elliptic curve cryptography) ephemeral public/private key pair according to the ECIES parameters provisioned by home network. The processing on UE side shall be done according to the encryption operation defined in [29]. with the following changes to Section 3.8 and step 5 and 6 of Section 5.1.3. - 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. The final output shall be the concatenation of the ECC ephemeral public key, the ciphertext value, the MAC tag value, and any other parameters, if applicable. NOTE: The reason for mentioning "any other parameter, if applicable" in the final output is to allow cases, e.g. to enable the sender to send additional sign indication when point compression is used. The Figure C.3.2-1 illustrates the UE's steps. Figure C.3.2-1: Encryption based on ECIES at UE