APM URL rewrite hash

I am assuming that for URL rewrite APM track the hosts with a hash of the host and something else. The logic seems to be as such –

 

“https://www.host.com/index.html” is rewritten to something like “https://apm.host.com/f5-w-<56 Hex characters>$$/index.html”

 

 

My question is how is it making this hash and what algorithms is it using ? I assumed that because it is 56 characters is that it is doing a SHA-224 hash. However, I have tried hashing my hostnames by themselves, adding http:// and https:// but the hashes aren’t the same as they come across in APM.

 

Thanks