A chosen-ciphertext attack (CCA) is an attack model for cryptanalysis in which the cryptanalyst gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an unknown key.

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The difference between these 4 breaking Cipher techniques?

I'm trying to understand the difference between the following and what they actually mean : Known plaintext attack Known ciphertext attack Chosen ciphertext attack Chosen plaintext attack Any ...
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Can you explain Bleichenbacher's CCA attack on PKCS#1 v1.5?

I've studied that the Bleichenbacher's CCA attack on PKCS#1 v1.5. is a base to many versions of attacks in the area. I'm trying to understand that attack, but every explanation I saw starts with the ...
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Common modulus attack on RSA when the 2 public exponents differ by a single bit

This is an exam question an i have no idea how to recover the message m. John wants to send an encrypted message to mary who has a pair of RSA keys, However, John does not know Mary's public key and ...
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Can a homomorphic encryption scheme be made CCA2 Secure?

Is it possible to modify a homomorphic encryption scheme so that it can be CCA2 secure? From the definition of a homomorphic scheme, it seems that it is malleable, which would result in lack of CCA2 ...
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Easy explanation of “IND-” security notions?

There are many schemes that can advertise themselves with certain security notions, usually IND-CPA or IND-CCA2, for example plain ElGamal has IND-CPA security but doesn't provide IND-CCA security. ...
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Secure double encryption using CPA and CCA

Do you mind if you give me any hints, links or ideas about how to improve the security of double regular encryption and decryption, by using CPA game and CCA game, it sounds interesting question, and ...
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Is the CBC weakness in XML Encryption a new discovery? Are other applications vulnerable?

The RUB in Germany reports that XML encryption is broken. This is essentially the W3C standard for protecting XML documents from prying eyes. Does this mean that an attacker can only see a single ...
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Why do we encrypt-then mac but sign-then-encrypt?

This question was asked in comments on my answer to should we sign then encrypt or encrypt then sign. I think posing the question as a separate entity is best, so: The general advice for applying ...
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How does a chosen ciphertext attack work, with a simple example?

Can someone please explain - using a simple example - how a chosen ciphertext attack works?