The only painful thing is that we must get the different strings for the different securityHandler from Acrobat itself since they aren't defined in the specifications.
Bug 1731578 Comment 1 Edit History
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The name of the security handler can be found in the `Encrypt` dictionary at the `Filter` entry: https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#page=64