What is a Timestamp?

Blockchain was invented for Time-stamping in 1991

Although Bitcoin is well known nowadays, the blockchain technology that powers it can be used for much more than just transferring money. Blockchain was originally invented for time-stamping documents, by Stuart Haber and W. Scott Stornetta in 1991. The Trusted Web is all about time-stamping content on the blockchain; making the internet trustworthy with the use-case that blockchain was invented for. But what exactly is a timestamp?

The idea is fairly simple: create a unique and universal fingerprint for every piece of content, based on simple inputs such as a titlethe content itself, and the date. This results in a unique fingerprint, let’s call it a hash. Some call it an ISBN for online content. 

This video explains what timestamping is, starting with the basics: hashing:

What is Hashing?

Hashing is a mathematical technique that has been used for decades. You can hash a character, text, document, or webpage with a hashing function. 

  • The same input always leads to the same output. 
  • But if you change 1 single bit in the original input, then the hash changes completely.
  • Although the input can be big or small, a single character or a big file, an outputted hash always has the same length. 
  • Another feature of hashing is that it is one way: it’s easy to go from an input to the output, a hash, but it’s hardly impossible to do the opposite, going from a hash to the input. 

Common names for the output of a hashing function are a hash or a fingerprint. WordProof adds that hash to a blockchain transaction, after which it can’t be altered or removed. This hash, stored in a blockchain, is what we call a timestamp.

Why is hashing useful?

  • A common use of hashing is password storage. If Facebook stores your password, they don’t store your password itself, but only a hash of it. A benefit, in this case, is security: if the data in Facebook’s database gets compromised, the thieves only get the hashes of the passwords, not your password itself! In this case, hashing brings security!
  • Now imagine doing bookkeeping in a big Excel spreadsheet. It can be a big file with hundreds of thousands of cells. If you only change one cell in the big document, the hash of the document changes completely. Remember? If I share the hash of the document publicly (for example on a blockchain), from that moment I can always prove that I didn’t tamper with my bookkeeping, without revealing the Excel sheet itself. 

The Trusted Web is about time-stamping all content that matters. From terms and conditions to news, from product information to government information, and so on. Thus, the website content is the input in this case. Your content has properties like the text, the title, and the date. Together, these items are the input for the hash. With this hash stored on a blockchain, magic happens: such a timestamp lets you prove beyond doubt that you didn’t change the content since the time of the transaction. 

You can see the timestamp as a certificate of birth for your content. With this unique hash, timestamped on a blockchain, you can prove to people, search engines, and social media platforms that you didn’t tamper with your content.