Introduction to Privacy
Introduction to the course and building foundation of blockchain and privacy
Privacy is a very important concept in blockchains, writing a smart contract is one thing, but designing the privacy aspects of your application is another, using cryptography as a toolbox can be a way to achieve privacy that can yield very good results. For example, hashes with salt has been used for a long time to store user passwords without actually knowing the user passwords and even if the security gets compromised and they are stolen, no user data can be accessed by using the hash without knowing the preimage of the hash.
Privacy is at the heart of blockchains, Blockchains such as Bitcoin and Ethereum are very public by nature, to use them for your applications, you must not put any sensitive data on them, but you have to put something so at a later date, you can prove that a supply chain holds or a product is legitimate, but how do you go about putting data on blockchains without really revealing what the data is?
There are many solutions to that problem, for example, a most commonly used one is hashing, a hash function is a deterministic one way function which takes a preimage and returns
hash = H(preimage)