How to find a free TPM handle to hold a new key pair object?

When using TPM (Trusted Platform Module), sometimes we need to find a free TPM handle to save a new key pair object. But how to find such a free handle? PHP editor Strawberry is here to share with you a simple and effective method. First, we can use TPM command line tools (such as tpm2_tool) to query the currently used handle list. Then, we can try handles one by one starting from 0x81000000 by looping through until we find a free handle. In this way, we can successfully save the new key pair object. Remember, you need to exercise caution when using TPM to ensure security and confidentiality.

Question content

I am new to TPM and currently working on a project involving generating and storing multiple key pairs using tpm. I would like to know how to find an available TPM handle that can be used to save a new key pair object. I searched for information on this topic but didn't find a clear answer. Here are some of my specific questions:

1. How do I programmatically determine if a TPM handle points to a blank area and can be used to save a new key pair object?

2. Are there any specific functions or methods in the Go-TPM package that can help me accomplish this?

3. What considerations or best practices should I be aware of when choosing a TPM handle to store a key pair?

I would appreciate any guidance, code examples, or references to relevant documentation that could help me understand how to find an available TPM handle to save a new key pair object in the tpm. Thanks in advance for your help. p>

This is what I tried:

1. Manually create a key pair using a specific handle (such as 0x81010001 or 0x81010002).

2. Attempt to save the key pair in TPM persistent memory.

Workaround

I don't know about the Go TPM library, but from a low-level perspective, you can use TPM_CAP_HANDLES's "nofollow noreferrer">TPM2_GetCapability Command (0x00000001) is used as the function parameter, 0x81000000 is used as the property parameter, for example, 32 is used as the propertyCount parameter.

This will return a list of allocated handles within the persistent object handle range, selecting an index that is not in the list and is in the range 0x81000000 - 0x817FFFFF.

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