SGX enclaves protect the code and data within from untrusted software, but do not retain their state when destroyed. Sealing allows preserving this data for future use by storing it outside the enclave boundary: the data is encrypted with a fresh secret key, and this key is bound to the processor that sealed the data and, either to the enclave measurement, or the public key of the enclave author. However, in a cloud environment, customers do not choose in which processor their code executes: the enclave that seals some data (for backup or future use) may be destroyed and later instantiated on a different processor or migrated to another processor. In those cases, the new processor would not be able to unseal the data, since the secret key is bound to the sealing processor.This paper presents Inter-Processor Attestation and Sealing (IPAS), a novel sealing mechanism for cloud environments and Intel SGX. In IPAS, sealed data is no longer bound to the sealing processor, but only to the enclave measurement or the public key of the enclave author, thus enabling other processors to unseal the sealed data. This is achieved without exporting the sealing secret key outside the enclave and without trusting third parties.

Humans constantly interact with computing devices. Many times, these interactions involve sensitive information and/or sensitive commands, leading to the need for trusted paths between humans and computers. For computer-to-computer interactions, secure communication is not an issue thanks to cryptographic protocols such as Transport Layer Security (TLS) and the IP Security Protocol (IPSec). However, the same does not yet apply to interactions between humans and computers due to the inability of humans to execute non-trivial cryptographic algorithms. This results in interactions that are vulnerable to shoulder surfing, man-in-the-browser malware, and web page spoofing, among other attacks. This consequently puts at risk the use of sensitive services in uncontrolled environments.We present TrustGlass, a scheme that uses augmented reality smart glasses to solve this security problem. TrustGlass uses such glasses to extend human capabilities, to execute the cryptographic algorithms needed to establish a trusted path between the user and the trusted service, which can be executed in a Trusted Execution Environment (TEE). With this approach, we can guarantee that only the user equipped with the glasses is capable of interacting with the service. We implemented TrustGlass using commercial smart glasses and show experimental performance and usability results.