How to obtain the crc32 value for a given file?

I am needing to calculate the crc32 value for a file which my app will download from the apps server.

This is to ensure that I have got the correct file (avoid middle man attacks).

However, my searches on the web has revealed nothing that can be done from within swift.

I am surprised as this would appear to be a basic need - even if other algorithms are being used as well.

Can I be pointed in the right direction for this ?

How to obtain the crc32 value for a given file?
 
 
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