Blockchain: Blueprint for a New Economy

translate back into the document (hashes

are only one-way; their security feature

makes back-computation impossible).

The retrieval phase of proof-of-

existence functionality can be thought of

as a “content verification service.”

Regarding longevity, the crucial part is

having the private key to the digital asset

(the hash) that is registered on the

blockchain. This does mean trusting that

whichever blockchain used will be

available in the future; thus, it would be

good to select an attestation service that

uses a standard blockchain like the

Bitcoin blockchain.

Limitations

Admittedly there are some limitations to

hashing-plus-timestamping blockchain

attestation services. First, a blockchain

is not required for timestamping,

because other third-party services

provide this for free, whereas a small

transaction fee (to compensate miners) is

required to post a digital asset

attestation to the blockchain. Also,

blockchain transaction confirmations are

not immediate; the time the document

was added to the blockchain is

recorded, not when the document was

submitted; and the precise time of digital

asset creation can be important in IP

registration services. Most

problematically, timestamping does not

prove ownership. However, blockchain

attestation services as currently

envisioned are an important first step

and could be incorporated in 3.0

versions that include other elements in

the blockchain ecosystem. Some ideas

propose including digital identity to

prove ownership and a non-blockchain-

based timestamping element for “time

document created.” A potential technical

limitation is the contention that the hash

might be less secure when you’re

hashing very large documents (an 8-GB

genome file, for example) compared to

small documents (a standard IOU

contract), but this concern is

unwarranted. The scalability to any file

size is the beauty of the hash structure,

and it is the hash length (typically 64

characters at present) that is the focus

for security, and it could be made longer

in the future. The usual threats to hash

technology—inverse hashes (an inverse

function to attempt to back-compute the

hashed content) and collisions (two

different files produce the same hash)—

are limited in the way hashes are

currently used in blockchain.

Virtual Notary, Bitnotar, and

Chronobit

Virtual Notary is another project that

similarly conceptualizes the need and

fulfillment of these kinds of blockchain

attestation services. Like Proof of

Existence, Virtual Notary does not store

files but instead provides a certificate

that attests to the file’s contents at the

moment of submission. The service

provides a certificate virtual notary-type

service for many different “file types”

such as documents, web pages, Twitter

feeds, stock prices, exchange rates,

weather conditions, DNS entries, email

address verifications, university

affiliations, real estate values,

statements and contracts, and random-

number drawing. Files can be in any

format, including Microsoft Word, PDF,

JPG, PNG, TXT, and PPT (Microsoft

PowerPoint). The site generates a

certificate that can be downloaded from

the site, and also offers the other side of

the service—examining existing

certificates. Virtual Notary’s aim is to

provide a digital, neutral, dispassionate

witness for recording online facts and

conveying them to third parties in a

trustworthy manner, a critical resource

as a larger fraction of our lives is now

digital. 102 Two other blockchain

timestamp projects are Bitnotar and

Chronobit. A similar blockchain-based

project for contract signing is

Pavilion.io, which provides the service

much cheaper than Adobe EchoSign or

DocuSign; contracts are free to send and

only one mBTC to sign.103 Two other

virtual notary projects are Blocksign and

btcluck.

Monegraph: Online Graphics

Protection

One digital-art protection project built

and intended as a proof of concept using

the blockchain ledger Bitcoin 3.0

applications related to new methods of

proof is Monegraph, whose slogan is

“because some art belongs in chains.”

Using this (currently free) application,

individuals can facilitate the

monetization of their online graphics—

digital media they have already created

and posted on the Web—by registering

their assets. Just as Bitcoin verifies

currency ownership, Monegraph verifies

property ownership; this is an example

of the smart property application of the

blockchain. Monegraph could be a

complementary service or feature for

stock photo image and graphic

repository websites like Shutterstock or

Getty Images, possibly adding future

functionality related to image use

enforcement and tracking.

Monegraph works in a two-step process

using Twitter, Namecoin, and

Monegraph. Namecoin is used because it

is an altcoin that can be used to verify

DNS registrations in an automated,

decentralized way; any similar DNS

confirmation service could be used.104

First, to stake the claim, the user goes to

http://www.monegraph.com/, gives it

permission to sign in to her Twitter

account (via the standardized Twitter

API OAuth token), and supplies the URL

of the graphic, upon which Monegraph