RSA加密：解密功能出错

Question

First post here. It is also my first time on coding on Python.

I really need help for my RSA encryption python project.

My decryption shows my wrong key error if I turn the decryption into a function. (Error: wrong key?) But when i join the decrypt function into my encrypt function, it works and decrypts the message that i have been encrypted.

Can I ask why? (I'm running it on Linux Ubuntu)

 import os
 import M2Crypto

def encrypt():

   pubkey = (raw_input('Enter choosen public key:'))
   loadpub = M2Crypto.RSA.load_pub_key (pubkey + '-public.pem')

   encrypt = (raw_input('Enter message to decrypt:'))
   CipherText = loadpub.public_encrypt (encrypt, M2Crypto.RSA.pkcs1_oaep_padding)

   print "Encrypted message:"
   print CipherText.encode ('base64')
   f = open ('encryption.txt', 'w')
   f.write(str(CipherText.encode ('base64'))) #write ciphertext to file
   f.close()

def decrypt():
   privkey = (raw_input('Enter choosen private key:'))
   loadprivkey = M2Crypto.RSA.load_key (privkey + '-private.pem')

   try:
    PlainText = loadprivkey.private_decrypt (CipherText, M2Crypto.RSA.pkcs1_oaep_padding)
   except:
    print "Error: wrong key?"
    PlainText = ""

   if PlainText != "":
    print "Message decrypted by " + privkey + " :"
    print PlainText

 def first():
  print "Press 1 for encryption."
  print "Press 2 for decryption."
  qwe = (raw_input(''))
  if qwe == '1':
    encrypt()
    first()
  elif qwe == '2':
    decrypt()
    first()
  else: 
    print "Please enter a correct number"
    first()

  if __name__ == '__main__':
    first()

Answer 1

In your new decrypt() function, CipherText becomes a new variable. You need to reload the contents of the file you wrote to in encrypt() into CipherText .

Previously, the variable would've still contained the data from your encryption process (when encryption and decryption were performed in the same function).