/highentropyva (Visual Basic)
Indicates whether a 64-bit executable or an executable that's marked by the /platform:anycpu compiler option supports high entropy Address Space Layout Randomization (ASLR).
If you specify this option, compatible versions of the Windows kernel can use higher degrees of entropy when the kernel randomizes the address space layout of a process as part of ASLR. If the kernel uses higher degrees of entropy, a larger number of addresses can be allocated to memory regions such as stacks and heaps. As a result, it is more difficult to guess the location of a particular memory region.
When the option is on, the target executable and any modules on which it depends must be able to handle pointer values that are larger than 4 gigabytes (GB) when those modules are running as 64-bit processes.
For more information about ASLR, see Mitigating Software Vulnerabilities.