[Cryptography] Is there a good algorithm providing both compression and encryption at the same time?

John Levine johnl at iecc.com
Tue May 12 11:54:19 EDT 2015

>At the same time, the IETF is pushing the encrypt everything agenda, and one of the big
>arguments is browsing privacy. You get arguments to encrypt Wikipedia to prevent censors
>from discovering which pages a particular user is reading. Wikipedia is public, but
>reading pages on homosexuality or abortion could get youths in trouble in many places. The
>argument goes that encryption will thwart the censors. Except of course that the encrypted
>traffic still reveal page lengths, compressed or not...

It would be quite a feat to figure out which Wikipedia page someone
was reading just from the page length, compressed or otherwise.
There's over 4,800,000 articles each of which can be rendered in many
different ways (talk, history, diffs, etc.), they change all the time,
and the size of a page depends on whether you're logged in and
probably on other stuff.  For example, I just retrieved a Wikipedia
page on a topic related to a river in the United States.  The
uncompressed length of the page was 47,068 bytes.  Free beer to the
first person who figures out what page it was.

HTTPS everywhere should be effective against casual snooping, e.g.,
watch all the web traffic through a proxy and look for naughty words.
It's certainly not a magic bullet against a determined opponent who's
looking at a specific target.


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