Re:One of the Most Alarming Internet Proposals I've Seen
by gojomo on Sunday February 23, 2014 @06:53PM
(#7288299)
It would need to be done via the pointer-to-content (URL/URI), and an independently-calculated secure-hash, not just a header. (The 'ni' proposal might serve this role.[1])
You definitely wouldn't use MD5, as experts have been recommending against its use for content-security since about 1996.[2] (A practical full chosen-preimage attack hasn't yet been developed, but still, you'd design for security for the next few decades, which would mean a SHA256 or better.) The choice of a good hash would mean no one could practically create an alternate file with the same hash.
You definitely wouldn't use MD5, as experts have been recommending against its use for content-security since about 1996.[2] (A practical full chosen-preimage attack hasn't yet been developed, but still, you'd design for security for the next few decades, which would mean a SHA256 or better.) The choice of a good hash would mean no one could practically create an alternate file with the same hash.
[1] http://tools.ietf.org/html/draft-farrell-decade-ni-10
[2] http://en.wikipedia.org/wiki/MD5#cite_note-30