TPM_IO_Hash_Start - Man Page


TPM_IO_Hash_Start — indicate the beginging of a TPM TIS hash operation

TPM_IO_Hash_Data — hash the provided data

TPM_IO_Hash_End — indicate the end of a TPM TIS hash operation


TPM library (libtpms, -ltpms)


#include <libtpms/tpm_types.h>

#include <libtpms/tpm_tis.h>

#include <libtpms/tpm_error.h>

TPM_RESULT TPM_IO_Hash_Start(void);

TPM_RESULT TPM_IO_Hash_Data(const unsigned char *data,
                           uint32_t data_length);

TPM_RESULT TPM_IO_Hash_End(void);


The TPM_IO_Hash_Start() function can be used by an implementation of the TPM TIS hardware interface to indicate the beginning of a hash operation. Following the TPM TIS interface specification it resets several PCRs and terminates existing transport sessions.  The TPM_IO_Hash_Data() function is used to send the data to be hashed to the TPM. The TPM_IO_Hash_End() function calculates the final hash and stores it in the locality 4 PCR. The 3 functions must be called in the order they were explained.

The implementation of the above functions handles all TPM-internal actions such as the setting and clearing of permanent flags and PCRs and the calculation of the hash. Any functionality related to the TPM's TIS interface and the handling of flags, locality and state has to be implemented by the caller.



The function completed sucessfully.


General failure.


The TPM_IO_Hash_Start() function was called before the TPM received a TPM_Startup command.


The TPM_IO_Hash_Data() or TPM_IO_Hash_End() functions were called before the TPM_IO_Hash_Start() function.

For a complete list of TPM error codes please consult the include file libtpms/tpm_error.h

See Also

TPMLIB_MainInit(3), TPMLIB_Terminate(3), TPMLIB_RegisterCallbacks(3), TPMLIB_Process(3)

Referenced By


The man pages TPM_IO_Hash_Data(3) and TPM_IO_Hash_End(3) are aliases of TPM_IO_Hash_Start(3).

2021-03-01 libtpms