Thanks for voting and commenting on this issue. Your feedback is key to helping us understand how you use JIRA so we can continue improving your experience. We have reviewed this issue over the last few days; unfortunately we don't have any plans to support this in JIRA for the foreseeable future.
There is add-on for JIRA Server available on the Atlassian Marketplace that may help resolve this request. However, for fine-grained security for files, we recommend keeping attachments in a dedicated document or file management application.
Please remember that jira.atlassian.com is one of many inputs for the JIRA roadmap. You can learn more about our process here.
I understand that our decision may be disappointing. Please don't hesitate to contact me if you have any questions.
Product Manager, JIRA Platform