[cross-posted to tahoe-...@allmydata.org and cryptogra...@metzdowd.com]
Disclosure: Cleversafe is to some degree a competitor of my Tahoe-
LAFS project. On the other hand, I tend to feel positive towards
them because they open-source much of their work. Our "Related
Projects" page has included a link to cleversafe for years now, I
briefly collaborated with some of them on a paper about erasure
coding last year, and I even spoke briefly with them about the idea
of becoming an employee of their company this year. I am tempted to
ignore this idea that they are pushing about encryption being
overrated, because they are wrong and it is embarassing. But I've
decided not to ignore it, because people who publicly spread this
kind of misinformation need to be publicly contradicted, lest they
confuse others.
Cleversafe has posted a series of blog entries entitled "3 Reasons
Why Encryption is Overrated".
http://dev.cleversafe.org/weblog/?p=63 # 3 Reasons Why Encryption is
Overrated
http://dev.cleversafe.org/weblog/?p=95 # Response Part 1: Future
Processing Power
http://dev.cleversafe.org/weblog/?p=111 # Response Part 2:
Complexities of Key Management
http://dev.cleversafe.org/weblog/?p=178 # Response Part 3: Disclosure
Laws
It begins like this:
"""
When it comes to storage and security, discussions traditionally
center on encryption. The reason encryption – or the use of a
complex algorithm to encode information – is accepted as a best
practice rests on the premise that while it’s possible to crack
encrypted information, most malicious hackers don’t have access to
the amount of computer processing power they would need to decrypt
information.
But not so fast. Let’s take a look at three reasons why encryption
is overrated.
"""
Ugh.
The first claim -- the today's encryption is vulnerable to tomorrow's
processing power -- is a common goof, which is easy to make by
conflating historical failures of cryptosystems due to having too
small of a crypto value with failures due to weak algorithms.
Examples of the former are DES, which failed because its 56-bit key
was small enough to fall to brute force, and the bizarre "40-bit
security" policies of the U.S. Federal Government in the 90's. An
example of the latter is SHA1, whose hash output size is *not* small
enough to brute-force, but which is insecure because, as it turns
out, the SHA1 algorithm allows the generation of colliding inputs
much quicker than a brute force search would.
Oh boy, I see that in the discussion following the article "Future
Processing Power", the author writes:
"""
I don’t think symmetric ciphers such as AES-256 are under any threat
of being at risk to brute force attacks any time this century.
"""
What? Then why is he spreading this Fear, Uncertainty, and Doubt?
Oh and then it gets *really* interesting: it turns out that
cleversafe uses AES-256 in an All-or-Nothing Transform as part of
their "Information Dispersal" algorithm. Okay, I would like to
understand better the cryptographic effects of that (and in
particular, whether this means that the cleversafe architecture is
just as susceptible to AES-256 failing as an encryption scheme such
as is used in the Tahoe-LAFS architecture).
But, it is time for me to stop reading about cryptography and get
ready to go to work. :-)
Regards
Zooko
---
Tahoe, the Least-Authority Filesystem -- http://allmydata.org
store your data: $10/month -- http://allmydata.com/?tracking=zsig
I am available for work -- http://zooko.com/résumé.html
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