I'm trying to understand Public Key encryption so I wrote this little module using PyCryptodome and the RSA/PKCS1_OAEP module on Python 3 to help me along. However, I keep getting an error:
NameError: name 'aesenc' is not defined
This is a two part question:
In standalone code (outside a class) the arg = default_val code will work, but I'm pretty sure this code will throw an error (assuming I fix question #2). I also know I can't use self.default_val as that needs an object to be created first. How do I assign a default value (in this case, the private/public key of the object?)
With regard to the error message, a vgrep reveals that the suite has been declared before its been called but I still get the NameError. Can someone please take a look and let me know what I'm doing wrong?
Modules: (Breaking into parts as SO keeps jumbling the code)
from passlib.context import CryptContext
from Crypto.Cipher import AES, PKCS1_OAEP
from Crypto.PublicKey import RSA
from Crypto import Random
from Crypto.Random import get_random_bytes
The Class:
class statEnc:
pubcipher = None
privcipher = None
pubkeystr = None
privkeystr = None
sessionkey = None
def __init__(self, pubkeystr = None, privkeystr = None, sessionkey = None):
self.pubkeystr = pubkeystr
self.privkeystr = privkeystr
self.sessionkey = sessionkey
if pubkeystr == None or privkeystr == None: #if blank, generate keys
self.random_generator = Random.new().read
self.keys = RSA.generate(1024, self.random_generator)
self.pubkey = self.keys.publickey()
self.pubkeystr = self.pubkey.exportKey(format='PEM',
passphrase=None,
pkcs=1)
self.pubcipher = PKCS1_OAEP.new(self.pubkey)
self.privcipher = PKCS1_OAEP.new(self.keys)
self.privkeystr = self.keys.exportKey(format='PEM',
passphrase=None,
pkcs=1)
self.privkey = self.keys.exportKey()
else: #import the keys
self.pubkey = RSA.importKey(pubkeystr)
self.pubcipher = PKCS1_OAEP.new(pubkey)
self.privkey = RSA.importKey(privkeystr)
self.pubcipher = PKCS1_OAEP.new(privkey)
if sessionkey == None:
sessionkey = get_random_bytes(16)
else:
self.sessionkey = sessionkey
def encrypt_val(self, session_key, cipher = pubcipher):
# a little ditty to hep encrypt the AES session key
try:
session_key = session_key.encode('utf8')
except:
pass
ciphertext = cipher.encrypt(session_key)
return ciphertext
def decrypt_val(self, ciphertext, cipher = privcipher):
# a little ditty to hep decrypt the AES session key
session_key = cipher.decrypt(ciphertext)
try:
session_key = session_key.decode('utf8')
except:
pass
return session_key
def aesenc(self, data, *args):
#encrypt the payload using AES
key = ''
if args:
if 'str' in str(type(args[0])):
try:
key = int(args[0])
except:
key = get_random_bytes(16)
else:
key = get_random_bytes(16)
try:
data = data.encode('utf8')
except:
pass
cipher = AES.new(key, AES.MODE_EAX)
ciphertext, tag = cipher.encrypt_and_digest(data)
aesencdict = {
'ciphertext' : ciphertext,
'tag' : tag,
'nonce' : cipher.nonce ,
'key' : key
}
return(aesencdict)
def aesdec(self, aesdict):
#decrypt the AES encrypted payload
cipher = AES.new(aesdict['key'], AES.MODE_EAX, aesdict['nonce'])
data = cipher.decrypt_and_verify(aesdict['ciphertext'], aesdict['tag'])
try:
data = data.decode('utf8')
except:
pass
return data
def end2enc(self, val, cipher = pubcipher):
# a master function to first encrypt the payload
val = str(val)
encval = aesenc(val)
# and then PK encrypt the key
encval['key'] = encrypt_val(encval['key'], cipher)
return encval
def end2dec(self, encval, cipher = privcipher):
encval['key'] = decrypt_val(encval['key'], cipher)
outval = aesdec(encval['aesdict'], encval['key'])
return outval
Test function and main:
def test():
val = { 'test' : "hello"}
keypair = statEnc()
print(str(type(keypair)))
encval = keypair.end2enc(val, keypair.pubcipher)
outval = keypair.end2dec(encval, keypair.privcipher)
print(val, outval)
if val == eval(outval):
return(val)
else:
return False
if __name__ == '__main__':
test()
[UPDATE] The Traceback is as follows:
[guha@katana stat]$ python statenc.py
<class '__main__.statEnc'>
Traceback (most recent call last):
File "statenc.py", line 124, in <module>
test()
File "statenc.py", line 115, in test
encval = keypair.end2enc(val, keypair.pubcipher)
File "statenc.py", line 100, in end2enc
encval = aesenc(val)
NameError: name 'aesenc' is not defined
