I am currently learning paillier cryptosystem,and have two questions about random r.I use the characteristics of homomorphic addition to obtain the product of two ciphertexts C and the corresponding plaintext P.
- Assuming I know the private key,how can I calculate r?(I want to know more details about how to calculate r)
- If I get r and send it to another person who only knows the public key, can he use (P,r) encryption to get ciphertext C to prove that my decryption operation is correct?