how to encrypt and decrypt with AES-256-CBC ?

[aragon5956]

Hello,
I would like to know , what length for my attributes in entities is necessary with a key of 32 bytes.Because 32*8=256, as my email for exemple ?

And i would like to know how to decrypt my fields with AES-256-CBC , and next, decrease length of my fields and then re-encrypt with AES-128-CBC ?

Regards