encryption/decryption help

[drs]

Hi, I need to send secure data over an insecure network.  To that end, I am
needing to encrypt serialized data and then decrypt it. Is there a builtin
way to do this in Python?  MD5, SHA, etc encrypt, but I am not seeing a way
to get back my data.  Encryption is totally new to me, so any pointers of
what to read up on would be appreciated.

As a side note, I understand that I could use https, but this would involve
changing things that I may not be at liberty to change -- though if this
turns out to be the best solution, then I'll find a way to use it.

Thanks