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New Project! PoC: Zepher TPM2 Software Stack

Hello and welcome,

I've got a link from a good friend of mine, and I want to share this with you:

Proof of Concept: Zepher TPM2 Software Stack

This repo tests the requirements (Code size and Memory size) for running tpm2-tss on Zephyr. The PoC is implemented on top of the Enhanced System API (ESAPI), since the Feature API (FAPI) adds additional dependencies to JSON-C and OpenSSL. Moreover, the tpm2-tools are also implemented on top of ESAPI, therefore the ESAPI should be sufficient.

And I'm really proud to see the first public-project that used the "new" Arduino2LetsTrust-Header. (I'll introduce the ArduinoAdapter in the next few days).

Bye for now!

Categories: TPM

Hello and welcome back!

Today I'm really happy and proud to introduce a new community around TPMs: was founded by Dimitar Tomov is a smart guy and he wants the same thing as I: Secure the world, a little more. wants to be a platform:
To discuss security toppings. (mostly TPM related)
For help if you stuck on your project. (offside an old school mailing list)
Collect more useful stuff around TPMs and OpenSourceSoftware for that.

And between Lockdown there is a funny little meetup every wednesday over MS-Teams. Really interesting people are there (some of them are customers of LetsTrust-TPMs ^__^)

So feel free to join the community!

Bye for now!


Categories: TPM

New fun fact!

Welcome back!

A few weeks ago Mr. M.P. write me an email with the question: May it possible to drive two TPMs on one Pi (4)?

Mr. M., want to drive one native TPM for the Pi and a second TPM as a remote vTPM for a client application.

So i've tested the Hardware Setting for Mr. M., after a few Minutes and combine this two posts:

Here the results:

Electrical- and mechanical-setting:

Hardware configuration of the two TPMs:

and you'll need 2 TPMs, with one 0Ohm Resistor on position CS0. [1]

Linux log

I hope this will be helpful for you, too.

Bye for now!


Categories: TPM

A new project is online!

Hello and welcome back!

Today I'll introduce you to a new TPM project.

Pierre Fontaine combines a Raspberry Pi, Yocto and a TPM.
He invested a lot of time on his project and I'll appreciate his work with a blogpost here, here is a qoute from his website:

The Raspberry, Yocto Project and The TPM!

In the cybersecurity field we need to play with crypto primitives. It allows us to authenticate for services (ssh, vpn ...), encrypt files for confidentiality, sign mail for proving your identity to the recipient, and even securing the boot of a complex device ...

So you do need to store keys and use crypto algorithms such as RSA, ECDH, AES compliant with some criteria (industry, military, medical ...).

Thank you Pierre to share you knowledge!

Here is the Link:
Raspberry Pi, Yocto and a TPM

By for now!


[1] © Copyright 2019. Jerome Blanchard, Romain Brenaget and Pierre Fontaine
Categories: TPM

aws iot greengrass with TPMs

Welcome to the November of posts,

Today: Using a Trusted Platform Module for endpoint device security in AWS IoT Greengrass!

The credits goes to:
The Infineon guys for build an example for use a TPM and pkcs11 in an AWS IoT greengrass environment and share it on github[1].
And Krishnan Ganapathy from amazon web services writes a blog article about it[2].

Thanks for the great work!

Bye for now!



Categories: TPM

Move LetsTrust-TPMs to CS0


The last time i get some questions about the chipselect configs for the module.

How you could move the default config from the LT-TPM CS1 to CS0.

If you want to use the TPM with CS0 you must change (resolder) the position of the 0Ohm Resistor to the open pads.

You'll see the difference if you open both pdfs:

If you don’t want to compile your device-tree-overlay by yourself, copy the tpm-slb9670-cs0.dtbo [1] to /boot/overlays/ and load the dtbo in the /boot/config.txt
over the setting dtoverlay=tpm-slb9670-cs0

If you want to decompile change and recompile the devicetree for the slb9670 for yourself:

1) sudo apt-get install device-tree-compiler
2) dtc -I dtb -O dts -o /mnt/boot/overlays/tpm-slb9670.dts /mnt/boot/overlays/tpm-slb9670.dtbo
3) cp mnt/boot/overlays/tpm-slb9670.dts /mnt/boot/overlays/tpm-slb9670-cs0.dts
4) dtc -I dts -O dtb -o /mnt/boot/overlays/tpm-slb9670-cs0.dtbo /mnt/boot/overlays/tpm-slb9670-cs0.dts

Bye for now!



PS: this will only work on the Raspberry Pis 0-4
Categories: TPM

Hardware update!


I've updated the pcb-design,[1]

Now we have the revision 2.2!

Changes from rev 2.0 to rev 2.2 [2]
Add 100nF capacitor on the RESET line of the TPM for a better POR (Power On Reset) behavior..
Change pad 1 from octagon to square, for better identify pin 1.
Add tiny labels on every pin on the bottom side (without MISO/MOSI/CLK, no place for the labels on these pins)

I added a legend in the schematics, for better reference if you want to use the TPM on your own Hardware design.

Placement and the schematic you will find in the right column.

Bye for now


[1] two months ago
[2] Revision 2.1 was never produced.
Categories: TPM

Project presentation -

Hello again,

in September this year I get mail from Luke Hinds, with some questions about the compatibility from LetsTrust-TPMs and RaspberryPis to check if will work for his project.

Now I proudly happy to link to this hilarious Project:

Quote from
“Keylime is about making TPM technology accessible for developers and users. It handles the complexity, you drive the use case!”

Thanks to Luke and all contributors of Keylime!

Bye for now,

Categories: TPM

vulnerability TPM-fail - LetsTrust-TPMs are not affected!

Welcome back!

no I´m not dead, \o/ ,
but the vulnerability ---TPM-fail--- need my highest attention today.

The good news: LetsTrust-TPMs are not affected!

But I'm not a friend of “hiding” information:

The SLB9670 that we used on our PCBs has the same certification levels on Common Criteria EAL4+ and FIPS 140-2 as the fTPM from Intel and the ST33 from STM.

If I get new information of the Chip on our LetsTrust-TPMs, I'll post an update here.

UPDATE: Quote from

Our analysis reveals that Intel fTPM and the dedicated TPM
manufactured by STMicroelectronics leak information about
the secret nonce in elliptic curve signature schemes, which
can lead to efficient recovery of the private key. As discussed
in Section 6, we also observe non-constant-time behavior by
the TPM manufactured by Infineon which does not appear
to expose an exploitable vulnerability.

Bye for now


UPDATE: Reference:


CVE-2019-11090 and impacts Intel's Platform Trust Technology (PTT).
CVE-2019-16863 and impacts the ST33 TPM chip made by STMicroelectronics.
Categories: TPM


Hello TPM friends,

after more than 18 months of work, compiling, testing, tears, blood...

Now you find the dto in the newest raspbian image, per default.

To activate the TPM on your Raspberry Pi you need only these simple commands:

sudo apt-get update
sudo apt-get upgrade
sudo nano /boot/config.txt

// and activate SPI with uncomment

// and load the TPM device tree overlay with

// save the config.txt

sudo reboot

// after the reboot

ls /dev/tpm0

// if you own a LetsTrust-TPM and plug it in the right way, you will get /dev/tpm0 in yellow letters

Thanks to all supportes :-)

Bye for now!