Quantum non-malleability and authentication

Understand

In encryption, non-malleability is a highly desirable property: it ensures that adversaries cannot manipulate the plaintext by acting on the ciphertext.

• Ambainis, Bouda and Winter gave a definition of non-malleability for the encryption of quantum data.
• In this work, we show that this definition is too weak, as it allows adversaries to "inject" plaintexts of their choice into the ciphertext.
• We give a new definition of quantum non-malleability which resolves this problem.