System and method for changing the security level of a communications terminal during operation

摘要

The security level of a communications terminal can be changed during operation. A key loading device can reconstitute a key encryption key from plural split portions. The split portions can be loaded into the key loading device via various interfaces. The reconstituted key encryption key can be used to unwrap wrapped keys stored in the key loading device.

主权项

1. A method of changing the security level of a communications terminal during operation, the method comprising:
providing a key loading device to the communications terminal, wherein the key loading device comprises a secure memory, and stored within the secure memory are: a wrapped first key (wK1) wrapped utilizing a single key encryption key (KEK) and a first split partial portion (s1KEK) of the single KEK but not a second split partial portion (s2KEK) of the single KEK or a third split partial portion (s3KEK) of the single KEK, wherein the single KEK cannot be reconstituted from less than all of the s1KEK, the s2KEK, and the s3KEK, wherein the s1KEK and the wK1 are at a first security level; loading the s2KEK into the secure memory of the key loading device via a physical interface to the key loading device; transferring the s3KEK into the secure memory of the key loading device via a communications link, wherein the communications link is different than the physical interface; and reconstituting the single KEK from the s1KEK, the s2KEK and the s3KEK, wherein the reconstituted single KEK is at a third security level higher than the first security level; unwrapping the wK1 using the reconstituted, single KEK to obtain a first key (K1), wherein the K1 is at a second security level higher than the first security level; and using the K1 within the communications terminal to perform cryptographic operations.