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Re: Bitcoin Is Not Quantum-Safe, And How We Can Fix It When Needed | Bitcoin Magazine

From: Dave Longley <dlongley@digitalbazaar.com>
Date: Wed, 18 May 2016 11:47:52 -0400
To: David Booth <david@dbooth.org>, Timothy Holborn <timothy.holborn@gmail.com>, W3C Credentials Community Group <public-credentials@w3.org>
Message-ID: <573C8EA8.1010107@digitalbazaar.com>
On 05/18/2016 11:14 AM, David Booth wrote:
> On 05/18/2016 10:58 AM, Dave Longley wrote:
>> On 05/17/2016 10:18 AM, Timothy Holborn wrote:
>>> It's an old article[1], wondering if their is any technical update
>>> since?
>>> [1]
>>> https://bitcoinmagazine.com/articles/bitcoin-is-not-quantum-safe-and-how-we-can-fix-1375242150
>> This is exactly why using public key cryptography that relies upon the
>> assumed difficulty of particular math problems to encrypt data on a
>> public blockchain is a bad idea.
>> This means that using today's common asymmetric encryption methods of
>> RSA/ECC to encrypt certain types of data on a public blockchain should
>> not be considered secure. That encrypted data is available to everyone
>> ... and it won't stay encrypted for all that long. This is especially a
>> problem for identity-related information, which is often sensitive and
>> has a long shelf life.
> What alternatives would you suggest?

I suggest never putting encrypted highly sensitive, long-lived data on a
public blockchain. I just don't think it's a viable option at all. Even
if you use hash-based encryption (quantum safe). You don't know if a
vulnerability in the algorithm will be discovered that will expose the
information. You can certainly put it on a private blockchain (or any
other storage mechanism) that requires some kind of
authentication+authorization access.

Just don't assume that encryption makes your data safe when it's
generally available to the public 24/7. Sensitive data is better
communicated across short-lived encrypted channels with perfect
forward-secrecy that, to be even be captured for later decryption,
requires well-timed, sophisticated hacking.

Dave Longley
Digital Bazaar, Inc.
Received on Wednesday, 18 May 2016 15:48:15 UTC

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