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Is there such thing as permanent EEPROM storage?
The data written should be un-deletable.
Once written it should be there as long as the chip is not destroyed or damaged.
Any other alternatives to EEPROMs are welcome.
I use DVD drives for PC. But I need a similar chip or system for microcontrollers.
Important: I don't want this to be implemented in my microcontroller Software by custom code. The Chip or IC or System it self should have that by default.
Link on Security.SE:
Yes -- what you are after exists, at least for small sizes. While most OTP EPROMs are parallel devices designed to be "burned" in dedicated EPROM programming hardware, Maxim makes exactly the part you're after in the form of the DS2505 -- 16kbits of in-system programmable OTP EPROM, with a unique serial number lasered into the chip as well that can be used to thwart chip replacement attacks.
You'll need a wee bit of drive circuitry as well as some bit-banging code to talk 1-Wire as the DS2505 requires its Vpp pulse to be muxed onto the 1-Wire interface along with normal power and data.
One of your comments suggests it has to be resistant to an 'inside attack'. Which will be difficult.
What do you actually want to achieve?
a) 100% reliable access to your data? If so, a denial of service attack, damage of the data or the chip would be a lose for you.
b) 100% reliable trust in the veracity of your data, so no alteration without detection? As you mention data valid until damaged in your OP, this could be sufficient, depending on whether 'destroyed' means the physical chip (or system it's embedded in) or the data on it.
If a) then you have an insurmountable problem if the attacker has physical access to the system. If he can zap the chip, or the system, or hit it with a hammer, really all bets are off if he has access.
If b) then you don't need any physical controls at all. A sufficiently strong cryptographic checksum stored with the data will tell you whether it has been altered in any way since writing.
So OTP and write bits are neither necessary (for b) nor sufficient (for a). Make sure you pick a solution that meets your real needs, and understand what you really need.
Yes, it's called a ROM, read only memory. A One Time Programmable (OTP) ROM is what you want. Alternatively an EEPROM with a Write Protection or Write enable pin that you can tie to VCC or GND to prevent rewriting. It's a less than 100% solution, if you have physical access, though you could just pour epoxy or potting compound over the EEPROM afterwards to make it really hard to write enable.
Other people have asked you to cover your ground rules already, so we know that whatever you put on can be damaged or removed if the aggressor has access to the components.
I don't know how much ROM data you need. But looking at what can be programmable by you and then stay 'tamper-proof', I'd suggest using a Lattice iCE40 FPGA such as an iCE40LP1K. It contains OTP configuration Flash, so you alone can programme it but no-one can read it or reprogramme it.
As per p6 of Lattice TN1248 'iCE40 Programming And Configuration':
"The NVCM contents are entirely contained within the iCE40 device and are not readable once protected by the one-time programmable Security bits. Furthermore, there is no observable difference between a programmed or un-programmed memory cell using optical or electron microscopy. The NVCM memory has a programming interface similar to a 25-series SPI serial Flash PROM. Consequently, it can be programmed using Diamond Programmer (version 2.2 or later) before or after circuit board assembly or programmed in-system from a microprocessor or other intelligent controller."
You then design an FPGA circuit to implement a ROM of your data and your communications port. That circuit is then loaded into the FPGA configuration from the internal OTP memory.
Your ROM communications port protocol is of your choice. It can be to a standard (e.g. SPI, I2C) or a made-up one that's difficult to understand by an intruder with a 'scope. I appreciate that obfuscation of data will not save you in your application but it will slow those intruders down a bit and its a cheap option.
Which device you need and whether an iCE40 can hold all your data depends how much you've got and I don't know that. Oh, and I think the iCE40 also has an internal oscillator but I'd need to check that.
Putting a conformal coating on to make it very difficult to observe pin activity seems a cheap option afterwards, if its of use. You can either have it done professionally or get medieval with a packet of Araldite.
Some chips have OTP areas that are for serialization information etc. It depends on the manufacturer and product line as to whether that is available on-chip though.
But EEPROM can be 'permanent' if you write your program so that it can't be overwritten!
