[Cryptography-dev] Getting Error message when trying to decrypt a message

[Alex Gaynor]

You're generating a new salt on every invocation of encryptMAIN, which
means that a different key is used when you encrypt and decrypt.

On Wed, Feb 22, 2017 at 1:29 PM, Salvador Munguia via Cryptography-dev <
cryptography-dev at python.org> wrote:

> Original Data:
> gAAAAABYrP0tuwZsZ2D5v-r7O6NyGDpp3-TeiEwGRy-HCZg6eWWzfGpr0teeZ3iOeI7YQlfE-
> xNr1cZLRUVQj2rgNcNS6rbJ
>
> Encrypted Data:
> gAAAAABYrdhsLhqsuFlsPn72AvzwXAT-_wJDQIIOzl5oFyoPzSrmmDbURiPRdTD
> fc_FqlOpTO0zGmedlyeY8xJp1_0D-2dwOh8VUs-0ncH604Zc38LKg7eZBJgIvSAByWMzJ
> -HagvTIC2FzQZW7xSJbHgXaI-p6kvbOKrRcZiwLvwyZOCJ1ivyrj1kD
> px06-jTLgZVD4VsWE7gHwQo2o4mj1_HtMRZevoA==
>
> Traceback (most recent call last):
>   File "tmp2.py", line 49, in <module>
>     dout = encryptMAIN(e_out,'')
>   File "tmp2.py", line 31, in encryptMAIN
>     return f.decrypt(data)
>   File "/usr/lib/python2.7/dist-packages/cryptography/fernet.py", line
> 110, in decrypt
>     raise InvalidToken
> cryptography.fernet.InvalidToken
>
>
> This is the code I am using:
> #!/usr/bin/python
>
> import zlib,MySQLdb,os,sys,urllib,re
> import os,hashlib,base64
> from cryptography.fernet import Fernet
> from cryptography.hazmat.backends import default_backend
> from cryptography.hazmat.primitives import hashes
> from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
> from Crypto.Cipher import AES
> from pbkdf2 import PBKDF2
>
>
>
>
>
> def encryptMAIN(data,fun):
>         password = b"this is the password!"
>         salt = os.urandom(16)
>         kdf = PBKDF2HMAC(
>         algorithm=hashes.SHA256(),
>         length=32,
>         salt=salt,
>         iterations=100000,
>         backend=default_backend()
>         )
>         key = base64.urlsafe_b64encode(kdf.derive(password))
>         f = Fernet(key)
>         if(fun == 'encrypt'):
>                 return f.encrypt(b"%s" % (data))
>         else:
>                 return f.decrypt(data)
>
> def encryptDATA(data):
>         cipher = encryptMAIN(data,'encrypt')
>         return cipher
>
> def decryptDATA(data):
>         decoded = encryptMAIN(data,'')
>         return decoded
>
> string = "gAAAAABYrP0tuwZsZ2D5v-r7O6NyGDpp3-TeiEwGRy-
> HCZg6eWWzfGpr0teeZ3iOeI7YQlfE-xNr1cZLRUVQj2rgNcNS6rbJ"
>
> e_out = encryptMAIN(string,'encrypt')
>
>
> print "Original Data: " + string
> print "Encrypted Data: " + e_out
>
> dout = encryptMAIN(e_out,'')
>
> print "Decrypted Data: " + d_out
>
>
>
>
>
>
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>
>


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