I would have preferred to write out "Analyis" but there was a character limit.

"I Know Why you went to the clinic: Risks of HTTPS Traffic Analysis" is 66 characters.

(Your're allowed up to 80.)

Then why did it tell me too many characters when I copied and pasted directly from the PDF?

(Feel free to try to replicate it. I actually spent a few minutes playing with ellipsises to find a different way to chop it.)

I've suggested a shortened edit of the original, if you compare my version to it.

Except that would be changing the title, which is verboten.

Untrue. Editing titles is specifically permitted to improve the title quality:

If the title contains a gratuitous number or number + adjective, we'd appreciate it if you'd crop it. E.g. translate "10 Ways To Do X" to "How To Do X," and "14 Amazing Ys" to "Ys." Exception: when the number is meaningful, e.g. "The 5 Platonic Solids."

Otherwise please use the original title, unless it is misleading or linkbait; don't editorialize.

https://news.ycombinator.com/newsguidelines.html

And shortening is specifically permitted as well:

https://news.ycombinator.com/item?id=21515548

https://news.ycombinator.com/item?id=31962722

https://news.ycombinator.com/item?id=31743041

I wouldn't mind if it's edited. I don't understand why I had the issue in the first place. Maybe I was copying excessive whitespace? I know that can happen if the original was done in latex.

AFAIU HN compresses out redundant whitespace.

The original title of the paper, "I Know Why You Went to the Clinic: Risks and Realization of HTTPS Traffic Analysis", is 83 characters.

HN's limit is 80.

Removing the words "and Realization" drops the character count to 67, well within HN's allowance. That's what I'd done in my alternate suggestion:

A: "I Know Why you went to the clinic: Risks and Realization of HTTPS Traffic Analysis"

B: "I Know Why you went to the clinic: Risks of HTTPS Traffic Analysis"

Lots of people go tp clinics for colonoscopies, so it's kinda Anal(ysis)...

Bit of a stretch I know...