Figure 5

We illustrate a decryption circuit for the ideal implementation of the fully quantum QPP. The said circuit is similar to the one for encryption, however, the qubits are initialized to the ciphertetx bits instead of the plaintext bits, and the order in which the operations are applied is different, For instance, the randomization in the decryption circuit is the last procedure that is acting on qubits, whereas for encryption is the second one. Moreover, the permutations are not dispatched form the Permutation Pad but rather the Inverse Permutation Pad. The Inverse Permutation Pad is applied to the ciphertetx qubits all together as one pad