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A core collapse supernova occurs when exothermic fusion ceases in the core of a massive star, which is typically caused by exhaustion of nuclear fuel. Theory predicts that fusion could be interrupted earlier by merging of the star with a compact binary companion. We report a luminous radio transient, VT J121001+495647, found in the Very Large Array Sky Survey. The radio emission is consistent with supernova ejecta colliding with a dense shell of material, potentially ejected by binary interaction in the centuries before explosion. We associate the supernova with an archival x-ray transient, which implies that a relativistic jet was launched during the explosion. The combination of an early relativistic jet and late-time dense interaction is consistent with expectations for a merger-driven explosion. 

We consider the problems of data maintenance on untrusted clouds. Specifically, two important use cases: (i) using public-key encryption to enforce dynamic access control, and (ii) efficient key rotation. Enabling access revocation is key to enabling dynamic access control, and proxy re-encryption and related technologies have been advocated as tools that allow for revocation on untrusted clouds. Regrettably, the literature assumes that data is encrypted directly with the primitives. Yet, for efficiency reasons hybrid encryption is used, and such schemes are susceptible to key-scraping attacks. For key rotation, currently deployed schemes have insufficient security properties, or are computationally quite intensive. Proposed systems are either still susceptible to key-scraping attacks, or too inefficient to deploy. We propose a new notion of security that is practical for both problems. We show how to construct hybrid schemes that are both resistant to key-scraping attacks and highly efficient in revocation or key rotation. The number of modifications to the ciphertext scales linearly with the security parameter and logarithmically with the file length.