How to use TPM in applications?

Question

How should the key generation and signature functions of TPM be implemented when attempting to use them in an application? In tbs. h, there are only functions that send commands. How can this command be constructed?

No robot's answer.

Thanks.

Answer 1

Hello,

Using the TPM (Trusted Platform Module) in applications involves interacting with its functionalities through commands and APIs. The TPM is a hardware-based security module that provides cryptographic functions and secure storage of keys. To implement key generation and signature functions using the TPM in your application, follow these general steps:

Initialize TPM Access:
To start using the TPM in your application, you need to establish communication with it. This is typically done through a software stack like the Trusted Platform Module Base Services (TBS). In Windows environments, you can use the TBS API provided by the tbs.h header.

Create a Key Pair:
To generate a key pair within the TPM, you'll use the appropriate TPM command and functions provided by the TBS API. The exact steps might vary depending on the algorithm and key size you're using. Generally, you'll send a command to the TPM to generate a key pair, and the TPM will return the public and private components of the key pair.

Use the Key Pair for Signing:
Once you have a key pair, you can use the private key to sign data. You'll prepare the data you want to sign and then use a signing command provided by the TPM to generate a digital signature using the private key stored in the TPM.

Verify Signatures:
In your application, you can then use the public key (which is part of the key pair) to verify signatures produced by the TPM. Verification involves applying the appropriate verification algorithm using the public key to ensure the integrity and authenticity of the signed data.

Here's a simplified example in C++ using the TBS API for Windows. Note that the code is illustrative and not complete; you would need to consult the TPM documentation and TBS API reference for more details.


#include <tbs.h>

// Initialize TPM access
TBS_CONTEXT_PARAMS2 contextParams = { sizeof(TBS_CONTEXT_PARAMS2) };
TBS_HCONTEXT hContext;
TBS_RESULT result = Tbsi_Context_Create(&contextParams, &hContext);

// Generate a key pair
TBS_HCONTEXT hContext;
TBS_RESULT result = Tbsi_Context_Create(&contextParams, &hContext);
BYTE publicKey[...]; // To store the generated public key
TBS_KEY_HANDLE hKey;
result = Tbsip_Context_CreateObject(hContext, TBS_CONTEXT_OBJECT_TYPE_KEY, TBS_CONTEXT_OBJECT_MODE_CREATE,
                                    &hKey);

// Sign data using the private key
BYTE dataToSign[...];
BYTE signature[...];
TBS_COMMAND_LOCALITY locality = TBS_COMMAND_LOCALITY_ZERO;
result = Tbsip_Submit_Command(hKey, TBS_COMMAND_PRIORITY_NORMAL, locality,
                              TBS_COMMAND_PRIORITY_NORMAL, dataToSign, sizeof(dataToSign),
                              signature, sizeof(signature));

// Verify signature using the public key
bool isValidSignature = VerifySignature(publicKey, dataToSign, sizeof(dataToSign), signature, sizeof(signature));

// Clean up resources
result = Tbsip_Context_CloseObject(hContext, hKey);
result = Tbsi_Context_Close(hContext);


Please note that this is a simplified example and might not cover all the intricacies of using the TPM. Working with the TPM requires a good understanding of cryptographic concepts and the specific TPM commands and capabilities available. Refer to the official TPM documentation and TBS API documentation for detailed guidance on constructing TPM commands, handling keys, and performing cryptographic operations.

If you have further questions do not hesitate to ask.

Hope this resolves your Query !!

--If the reply is helpful, please Upvote and Accept it as an answer–