# Tag Info

1

No they are different. A covert adversary is essentially just a relaxation of a regular malicious adversary. Rational cryptography, on other the hand, is a different way of analyzing a cryptographic scheme using game theory. Here the parties of a protocol are seen as rational in a game theoretic sense acting according to some utility. I am not very well ...

2

The way I see it, you have a few options. The right one will depend on the details of the application, which are sparse in the question. Use a stream cipher (or stream-like mode). Each party has a separate key and encrypts/decrypts with their individual key. With this you only get n-out-of-n, not m-out-of-n where $m<n$. Use MPC. You can evaluate the AES ...

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$A$ has outsourced it's private data to the server, right? In that case $A$'s private data has already been leaked to the adversary when the server was corrupted. So there is no added leakage in $B$ also learning this data. In fact since only one of $B$ and the server can be corrupted (assuming static corruptions) we can conclude that $B$ is honest, and ...

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