If we have private data, encrypted using best practices (salted, 2048bit keys, private keys stored off line, etc), is it considered safe to post this encrypted data in a publicly accessible location?<p>Imagine if everyone encrypted and published a tarball of their email history. Would this data be considered "vulnerable" to attacks ?
Any form of encryption can be cracked eventually, given enough time and processing power. What if a new type of supercomputer is invented tomorrow that can crack 2048 bit in minutes? Not publishing your data would give you the opportunity to re-encrypt using the latest method.
One must assume encrypted content will not be safe in the future. I would also be leery of anything that says "perfect". e.g. Perfect Forward Secrecy. In the future, we may be making fun of that.