CODEWITHSUNDEEP
pythonpycrypto
Emma Bell
Emma Bell

Reputation: 11

TypeError: argument must be string or read-only buffer, not bytearray

I'm building a decryptor using DES ECB

from Crypto.Cipher import DES

code = 'cb9108614c943d96bedd2bae934c5aa3d5c4318f81cc81f255127292f2935bbc0a8990f36c1ffa20a0639ed8a6989bacc36bd11f6b2ecdab'
key = b'5199D19B'
code= bytearray.fromhex(code)

print(code)

ciphert = DES.new(key, DES.MODE_ECB)
code = ciphert.decrypt(code)
code = code.decode('ISO-8859-1')

print(code)

but I keep getting this error

File "test.py", line 17, in

code = ciphert.decrypt(code)

File "build/bdist.macosx-10.14-intel/egg/Crypto/Cipher/blockalgo.py", line 295, in decrypt

TypeError: argument must be string or read-only buffer, not bytearray

Ive been working on this for hours now and can't figure out another way to store the variable.

Any ideas?

Upvotes: 0

Views: 2555

Answers (1)

Iguananaut
Iguananaut

Reputation: 23296

I think this is what you want:

>>> from Crypto.Cipher import DES
>>> code = 'cb9108614c943d96bedd2bae934c5aa3d5c4318f81cc81f255127292f2935bbc0a8990f36c1ffa20a0639ed8a6989bacc36bd11f6b2ecdab'
>>> key = b'5199D19B'
>>> ciphert = DES.new(key, DES.MODE_ECB)
>>> ciphert.decrypt(code.decode('hex'))
'Well done, you have been able to decode the message. \x00\x00\x00'

Generally when passing ciphertext to a "decode" function in crypto libraries it should be passed as a bytes object (as ciphertext can contain arbitrary bytes in general). For whatever reason it just doesn't accept a bytearray object--that would have to be implemented separately.

code.decode('hex') does the same thing you wanted--it converts a string of hex digits to their actual byte values.

Update for Python 3:

On Python 3 code.decode('hex') won't work. Instead use bytes.fromhex(code) (similarly to bytearray.fromhex but just return an immutable bytes instance).

Upvotes: 1

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