# Tag Info

## Hot answers tagged chosen-plaintext-attack

3

The idea behind these models is to model an adversaries capabilities. To get reliable security the worst case for a capability is modelled. Let's start with chosen plaintext attacks (CPA): In this game the adversary is given access to an encryption oracle. This models the case where an attacker knows (parts of) the message. For example, the British knew ...

2

"What prevents an attacker from just sending the received ciphertext to the recipient who will think that this is the legitimate message?" Nothing. $\:$ (In that case, the recipient will be correct.) Why "in the definition" is the attacker "only allowed to send another" message? If he knows before seeing the ciphertext that it will be an encryption of ...

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