Request for help to select an appropriate FPGA IC?

[Altera_Forum]

Hi all; 

 We need an FPGA to design and implement a security token that acts such a Smart Card or HSM or ...   We'd like to select an FPGA with high capabilities and low price off course!Since we should produce the tokens in a large number, it's better the FPGA IC's price to be low between 10$ to 15$.   Could you guide me to select an appropriate one?   And the other question:   What would be the minimum circuit to drive a complete and working FPGA based module? I mean additional elements required for correct & exact operation of circuit, such as, adding a crystal to one of AVR microcontroller inputs?   Any experience based suggestion or schematic hint or useful internet link will be greatly appreciated. (BTW, I've not worked by FPGA so far, so if possible, explain simpler and in more details please!)   TIA.

[Altera_Forum]

for $10-15, you wont get much more than the lowest end of altera devices. 

 The big question is, what do yo really need it to do?

[Altera_Forum]

Why do you need an FPGA?

[Altera_Forum]

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.

[Altera_Forum]

I don't know how to estimate how much logic you'll need, so it's hard to recommend a device. 

 If the logic is small enough, I'd go for a MAX II or MAX V device. They're the cheapest, have a small EEPROM I think will be useful for you and require the fewer external components.  You can download, for free, Quartus and start putting together a prototype design before committing to device.  If you need a bigger device, the option is the Cyclone III E or LS or Cyclone IV E family. These are more expensive and require more external components, including an external EEPROM. The Cyclone III LS family has the advantage of allowing the configuration (which is stored in the external EEPROM) to be encrypted. But this requires a small battery to keep the decrypting key in the FPGA.   Regarding external components...   Configuration: - MAX II/MAX V require a connector and a couple of resistors for JTAG; ; you may also want to have a JTAG interface for the Cyclones. - Cyclone srequire an external EEPROM and a couple of resistors for the FPGA configuration interface.  Voltage regulators, depending on your system and device. Some MAX II devices can be operated using only a single 3.3V supply. Other MAX II/V will need a 1.8V supply, plus 3.3V if you want 3.3V I/Os. Cyclones will need even more supplies..  Level shifters: the MAX II/V and Cyclone FPGA can only handle signals up to 3.3V.  If you need 5V or more, you may need more components.

[Altera_Forum]

Can't you use a microcontroller for that application instead of an FPGA or CPLD? You would require next to no external components, and it is more in your price range. I don't see the benefit of programmable logic for this application, except if the cryptographic requirements ask for a hardware acceleration, but in that case a Max II will probably not be enough and the FPGA solution will cost more than what you want anyway.