Hello All,

First, I hope you are safe and doing fine in the unfortunate COVID-19 situation. I am a Ph.D. student at the University of Central Florida. Currently, I am working on a TEE-based prototype application for a proof-of-concept. Since I am totally new in this domain, so it is taking some effort. I have a few questions and I hope you guys can help me in that.

At present, I am able to set up OP-TEE on Qemu and run the examples on the normal world and the secure world. Additionally, I tweaked a few parameters (ie., the integer value in the main.c) for the CA and the addition and subtraction sequence in the TA. Upon building it again (cd/build/make all run), it seems to work. However, if I need to pass a normal string to the TA and the TA computes Sha256 of the string and returns the value, what steps do I need to take? In other words, how can I pass a tuple from the TA to the CA and obtain the Hash of the tuple. Additionally, if I am able to do that by tailoring the HelloWorld examples, how can I develop new CA and TA with unique UUID and perform the same procedure. Finally, instead of doing the entire (cd/build/make all run), is there a method by which I can simply build the application and alone and run it on Qemu?

I understand that these must be trivial questions, however, I will deeply appreciate if you can help me in figuring them out.

Best,

Saad