Any way to MD5 hash a string within WiX?

I have been googling and read through the WiX tutorial (http://www.tramontana.co.hu/wix/), but I am unable to see a simple way to create an MD5 hash of 开发者_如何学JAVAa string/property. Does anyone know of any built in WiX Installer methods to do this or is my only option a custom action?

I am currently using WiX version 3.5.

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There's nothing in WiX or MSI to hash a string.