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Faliure of indistinguishablity of encryptions under a eavesdropper does imply faliure of indistinguishablity of encryptions under a chosen-plaintext attack. But the converse is not necessarily true (ex. OTP) The aim of CPA-secure is not to decrypt previously unobserved ciphertext but to pass the distinguishability test after a set of (plaintext, ciphertext) ...


As fgrieu already said, the question is a bit weird. The encryption scheme is not complete in a very strong sense, as there exists no efficient algorithm that can recover $m$ from a ciphertext. But anyway, the definition of CCA security does not require completeness, so let me just answer the question as asked: No the scheme as described is not CCA secure ...

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