Blockstack binds (human-readable) domains to Public Keys to establish ownership of domains. These domains have associated data records as well. These small bindings are stored on the blockchain and are tamper resistant. The actual payload from the data records is stored outside of the blockchain because blockchains have limited data space and are not meant to be used as general-purpose databases.
Blockchains don’t have central points of trust or control, and Blockstack nodes can use the Blockstack blockchain to boot up and connect to the new decentralized internet without relying on any remote servers.
Blockstack’s blockchain is built using a technology that we introduced earlier, called virtualchains. Virtualchains are to blockchains what virtual-machines are to physical computers. By using virtualchains for implementing a blockchain, Blockstack can survive the failures of underlying blockchains. Blockchains will come and go, but the apps built on top need to outlast the underlying blockchains.
Blockstack is the first implementation of a decentralized Domain Name System on top of the Bitcoin blockchain [2]
Blockstack combines Domain Name System functionality with Public Key Infrastructure and is primarily meant to be used by new blockchain applications. [2]
Blockstack is being developed by a group of engineers and researchers coming from both industry and academia and is released as Open Source. Other systems like Namecoin have implemented decentralized DNS using blockchains earlier by using blockchains other than Bitcoin. Blockstack became operational on the Bitcoin blockchain in September 2015. As of March 2016, Blockstack was the largest non-financial system using the Bitcoin blockchain by transaction volume. [2]
With Blockstack Applications you own your Digital Identity. Your digital keys are seamlessly generated and kept on your device. This lets you move freely between apps and control your online experience.