pycrypto 3DES keysize

[hg]

hg wrote:

> Ning wrote:
> 
>> I'm trying to write an IM client which sends encrypted messages to the
>> server.  I tried to use pycrypto library, but when I came to 3DES
>> cypher I was confused about the keysize to use.  In the standard it
>> said that it should be either 112 bits or 168 bits, whereas it's 16
>> bytes or 24 bytes in pycrypto.  If I use 16 bytes key to encrypt and
>> send this key to the server which is expecting a 112 bits key, there'll
>> be a problem.  How I should solve this?
> 
> You need to account for the parity bits:
> http://en.wikipedia.org/wiki/Triple_DES
> 
> 
> If that may reassure you ;-) I use PyCrypto to "talk" to smart cards
> without any problem.
> 
> hg


PS: as stated in the wiki, I would seriously consider AES as it is safer /
faster / supported by pycrypto

hg