A method executed by a first electronic device (ED1) includes splitting a selected secret for backup into a plurality of N secret shares in a trusted execution environment (TEE) of the ED1. The method includes transferring, via the transceiver over a short-range transmission, the N secret shares to N trustee devices, by transferring each secret share from among the N secret shares to a different trustee device from among the N trustee devices. Each secret share is configured to cause the trustee device to store the secret share in a TEE of a trustee device upon receipt by the trustee device. The method includes receiving, from the trustee device, one of an acknowledgement confirming the transferred secret share is stored in the TEE of the trustee device or an error warning the transferred secret share is not stored in the TEE of the trustee device.