不清楚

Question

Pycryptodome官方的例子，我有https://www.pycryptodome.org/en/latest/src/examples.html#encrypt-data-with-rsa

from Crypto.PublicKey import RSA 
from Crypto.Random import get_random_bytes 
from Crypto.Cipher import AES, PKCS1_OAEP 

file_out = open("encrypted_data.bin", "wb") 

recipient_key = RSA.import_key(open("receiver.pem").read()) 
session_key = get_random_bytes(16) 

# Encrypt the session key with the public RSA key 
cipher_rsa = PKCS1_OAEP.new(recipient_key) 
file_out.write(cipher_rsa.encrypt(session_key)) 

# Encrypt the data with the AES session key 
cipher_aes = AES.new(session_key, AES.MODE_EAX) 
ciphertext, tag = cipher_aes.encrypt_and_digest(data) 
[ file_out.write(x) for x in (cipher.nonce, tag, ciphertext) ] 

一個問題，它說我應該使用cipher.nonce，但cipher在例如不確定的。我應該用

cipher = AES.new(key, AES.MODE_EAX) 
cipher = AES.new(key, AES.MODE_EAX, nonce) 

還是別的什麼？我敢打賭cipher = AES.new(key, AES.MODE_EAX, nonce)，但我想確保它是密碼安全的。那麼key所需的cipher應該是recipient_key，對嗎？

Answer 1

此代碼有效，但我不確定它的安全性，所以如果有人可以證實這一點，將不勝感激。

from Crypto.PublicKey import RSA 
from Crypto.Random import get_random_bytes 
from Crypto.Cipher import AES, PKCS1_OAEP 

data = "abc".encode("utf-8") 

#print (open("pubkey.der").read()) 
recipient_key = RSA.import_key(open("pubkey.der").read()) 
session_key = get_random_bytes(16) 
cipher_aes = AES.new(session_key, AES.MODE_EAX) 

# Encrypt the session key with the public RSA key 
cipher_rsa = PKCS1_OAEP.new(recipient_key) 

# Encrypt the data with the AES session key 
ciphertext, tag = cipher_aes.encrypt_and_digest(data) 
enc_session_key = (cipher_rsa.encrypt(session_key)) 
encoded = [x for x in (cipher_aes.nonce, tag, ciphertext, enc_session_key) ] 

#------------------------------------------------------ 

(cipher_aes_nonce, tag, ciphertext, enc_session_key) = encoded 

private_key = RSA.import_key(open("privkey.der").read()) 

#print (enc_session_key, cipher.nonce, tag, ciphertext) 

# Decrypt the session key with the public RSA key 
cipher_rsa = PKCS1_OAEP.new(private_key) 
session_key = cipher_rsa.decrypt(enc_session_key) 

# Decrypt the data with the AES session key 
cipher_aes = AES.new(session_key, AES.MODE_EAX, cipher_aes_nonce) 
data = cipher_aes.decrypt_and_verify(ciphertext, tag) 

print (data.decode("utf-8"))