What does CCA secure mean?

A chosen-ciphertext attack (CCA) is an attack model for cryptanalysis where the cryptanalyst can gather information by obtaining the decryptions of chosen ciphertexts. From these pieces of information the adversary can attempt to recover the hidden secret key used for decryption.

What is the aim of chosen ciphertext security?

The aim of this work is to provide a generic transformation to make any encryption scheme, whose one-wayness is provable, semantically secure even against adaptively chosen-ciphertext attacks, adding just the random oracle as- sumption.

What does CPA security mean?

chosen-plaintext attack
A chosen-plaintext attack (CPA) is an attack model for cryptanalysis which presumes that the attacker can obtain the ciphertexts for arbitrary plaintexts. The goal of the attack is to gain information that reduces the security of the encryption scheme.

What are the types of attacks on encrypted message?

Having seen, the basics of cryptography and the different types of encryption, let us next view the different types of attacks that are possible. There are two types of attacks – ‘passive attacks’ and ‘active attacks’.

Is OFB mode secure?

The block cipher modes ECB, CBC, OFB, CFB, CTR, and XTS provide confidentiality, but they do not protect against accidental modification or malicious tampering. Modification or tampering can be detected with a separate message authentication code such as CBC-MAC, or a digital signature.

What is semantic security in cryptography?

Definition. Semantic security is a notion to describe the security of an encryption scheme. An adversary is allowed to choose between two plaintexts, m0 and m1, and he receives an encryption of either one of the plaintexts.

Is AES CPA secure?

Block ciphers, including AES, are not IND-CPA secure on their own because they are deterministic. In other words, encrypting the same message twice with the same key produces the same output twice.

Is ciphertext encrypted?

Ciphertext is encrypted text transformed from plaintext using an encryption algorithm. Ciphertext can’t be read until it has been converted into plaintext (decrypted) with a key.