# Tag Info

## New answers tagged provable-security

1

M connects the two enciphered parts of the second message so that $S$ can detect a message constructed from parts of previous messages by an intruder. Other protocols of the time used double encipherment to do the equivalent. Double encipherment required either two enciphering engines or a path for arbitrary data that bypasses the enciphering engine. This ...

2

Edit. Except for CPA1 (defined by the OP), "CPA" below refers to multi-challenge CPA, where the adversary always submits two messages and receive the encryption of either the first or the second messages. It's equivalent to the usual one-challenge multi-query CPA. CPA1 is equivalent to CPA. Consider real-or-random CPA (RRCPA), where the adversary adaptively ...

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