Diploma.report is a Blockchain authentication service meant to serve the needs of graduates, schools, universities and recruiters. Authenticating electronic copies of a diploma saves the energy and paper consumed by the process of sending and verifying a paper document. In addition, diplomas authenticated in the Bitcoin Blockchain are much less prone to counterfeiting attempts. Diploma.report was developped using free software, notably ruby-on-rails, bitcoin-ruby and money-tree. Free blockchain explorers such as blockcypher.com or blocktrail.com can be used to check bitcoin OP_RETURN transactions. We should all be very grateful for the work of the free software developpers who are building such great tools and making them available to us.
What makes diploma.report so powerful as a secure file certification mechanism, is that you can check your local file digest by yourself. There is no need for a third party to verify that the digest (hash) of your local copy of the file matches the digest (hash) logged in the blockchain.
Only the digest of your file, not the file itself, is publicly visible in the blockchain as a transaction ouptput. It is embedded as a special kind of Bitcoin transaction outputs known as "OP_RETURN" outputs. Those outputs are not spendable, i.e carry zero monetary face value but are stored in the blockchain just as securely and permanently as any other transaction output.
On OSX or Linux, open a terminal window and verify your local file sha256 digest (hash) by yourself (avoid space caracters in file names or folder names, if any, replace with underscore caracters, hash computation result is independent of file name): $ irb 2.2.0 :001 > require 'digest' => true 2.2.0 :002 > sha256 = Digest::SHA256.file '/Users/noizat/Documents/Bitcoin_book_2012.pdf' => #<Digest::SHA256: 99368fbbbbb6cbebfcc436f97da3ef97dfb28f37c16ae13cd484a166f251dba0> 2.2.0 :003 > sha256.to_s.unpack('H*').first => '39393336386662626262623663626562666363343336663937646133656639376466623238663337633136616531336364343834613136366632353164626130'
Most block explorers will display the "OP_RETURN" data as a 64-character hexadecimal string (e.g. above "99368fbbbbb6cbebfcc436f97da3ef97dfb28f37c16ae13cd484a166f251dba0") Be aware, however, that some other, less clever block explorers will display the same string only as a cumbersome 128-character hexadecimal encoded string (e.g "39393336386662626262623663626562666363343336663937646133656639376466623238663337633136616531336364343834613136366632353164626130"). To prevent any confusion, diploma.report displays the file hash encoded in both string formats.
If you do not feel comfortable using the command line terminal of your computer, you can simply compute the SHA256 hash of any file on this page: click HERE to select the file in your computer hard drive. The file will NOT be uploaded. The file hash computation is performed client-side.