Writing/Reading .dat Files?

seeing as '.dat' files contain only what you want them to and there is no preset encryption for them etc could I write data to one by using this simple process:

1) Change file extension to '.txt'
2) Decrypt
3) Write
4) Encrypt
5) Change file extension to '.dat'

and pretty much the same for reading it. or am I thinking to simply?

I thought of the above way as i know how to write to text files already, but is this the best way to do it? or is there a better way?

EDIT: Nevermind you just write to it like a text file and encrypt/decrypt it. request lock/delete from mod.