Suppose I have a device in an environment that isn't physically secure, but I need to store some confidential data on it. The data volume is too large for a smartcard. What hardware platform would offer some tamper resistance?
- Computing power of the same order of magnitude as a Raspberry Pi
- at least 512 MB of RAM
- USB or Ethernet connectivity
- Tamper-resistant key storage and secure boot
I'm looking at a fairly low point on the security/cost price point. Let's say less than $100 — not an HSM. But it should offer some security against a casual attacker. With a Raspberry Pi, it's trivial to pull out the SD card and extract the data at one's leisure.
Is there a similar board at this price point where dumping the requires at least unsoldering the RAM or the flash memory? What about a higher level of security — what's the cheapest device that would require probing inside the package? (Assume no software vulnerability.)
Note that combining an unsecure device with a smartcard does not meet the security requirements, since the card has no way to know whether it's unlocking the legitimate device or the attacker's.
This is for a one-off use, not a mass production run.