US Patent 10396981 Pre-personalization of electronic subscriber identity modules

Methods for provisioning electronic Subscriber Identity Modules (eSIMs) to electronic Universal Integrated Circuit Cards (eUICCs) are provided. One method involves a provisioning server configured to encrypt the eSIM with a symmetric key (Ke). The provisioning server, upon identifying a target eUICC, encrypts the symmetric key with a key encryption key (KEK) derived based at least in part on a private key associated with the provisioning server and a public key associated with the target eUICC. The provisioning server generates an eSIM package including the encrypted eSIM, the encrypted symmetric key, a public key corresponding to the private key associated with the provisioning server, as well as additional information that enables the target eUICC to, upon receipt of the eSIM package, identify a private key that corresponds to the public key associated with the target eUICC and used to derive the KEK.