Did you ever find the answer to your question? If you do have the answer, please post it on this forum. I have looked high and low for Adobe's SHA1 Hash of the AdobeFlashPlayer_18au_a_install.dmg file, which is the Adobe download that installs the security update Adobe Flash 188.8.131.52. Thanks
Here is a link which contains some of the files:
Filename and MD5 checksum
Well there are lots of downloads. But only one source: Adobe.com. Everyone else is unauthorised - Adobe do not give redistribution rights. And hence, suspect. I think we've moved on from hashes to signed distributions, but I'm not sure I favour either one.