Request for help to select an appropriate FPGA IC?

Thanks and sorry for delay in reply!

As I said in my post, I need an FPGA to design and implement a security token that acts such a Smart Card or HSM or ...

I want the FPGA Ic, itself, to be 10-15$. Not the other required elements

such as carrier board.

Indeed, the main goal is to implement security machanisms or cryptographic algorithms to encrypt/decrypt, sign/verify, check pin and ...

Now:

What programmable Ic do you suggest for this purpose and Why?

FPGA or...?

If FPGA, What type and model please (with regard to price, off course!) ?

Thanks again.