EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS - NtDoc

#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

// Indicates authentication and time stamp requirements that must be met before writing to this firmware environment variable.
// When this attribute is set, the buffer, represented by Buffer, will begin with an instance of a complete (and serialized) EFI_VARIABLE_AUTHENTICATION_2 descriptor.
#define EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 0x00000020

#endif
#endif
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