ChainLink is a powerful, widely deployed protocol that allows users to access web data over confidential, integrity-protected channels. But TLS has a serious limitation: it doesn’t allow a user to prove to third parties that a piece of data she has accessed authentically came from a particular website. As a result, data use is often restricted to its point of origin, curtailing data portability by users, a right acknowledged by recent regulations such as GDPR . Specifically, when a user accesses data online via TLS, she cannot securely export it, without help (hence permission) from the current data holder.
Vast quantities of private data are thus intentionally or unintentionally locked up in the “deep web”—the part of the web that isn’t publicly accessible.To understand the problem, suppose Alice wants to prove to Bob that she’s over 18. Currently, age verification services  require users to upload IDs and detailed personal information, which raises privacy concerns. But various websites, such as company payroll records or DMV websites, in principle store and serve verified birth dates.
ChainLink Key Information
|ICO start||25th Sep 2017|
|ICO end||10th Oct 2017|
|Tokens for sale||1,000,000,000,000|
|Soft cap||5,000,000 USD|
|Price in ICO||1 SPH = 0.01 USD|
|Whitepaper||Click Here For View Whitepaper|
|Website||Click Here For Visit ICO Homepage|
The Game Change Team Behind ChainLink
Smart Contracts’ Execution Guarantees
Smart contracts are applications that execute on decentralized infrastructure, such as a blockchain. They are tamper proof, in the sense that no party (even their creator) can alter their code or interfere with their execution. Historically, contracts embodied in code have run in a centralized manner that leaves them subject to alteration, termination, and even deletion by a privileged party.
ChainLink contrast, smart contracts’ execution guarantees, which bind all parties to an agreement as written, create a new and powerful type of trust relationship that does not rely on trust in any one party. Because they are self-verifying and self-executing (i.e., tamper proof as explained above), smart contracts thus offer a superior vehicle for realizing and administering digital agreements.
Designing DECO with the required security and practical performance, while using legacy-(TLS)-compatible primitives, introduces several important technical challenges. The main challenge stems from the fact that TLS generates symmetric encryption and authentication keys that are shared by the client (prover in DECO) and web server. Thus, the client can forge arbitrary TLS session data, in the sense of signing the data with valid authentication keys.
ChainLink address this challenge, DECO introduces a novel three-party handshake protocol among the prove, verified, and web server that creates an unforgettable commitment by the proverb to the verified on a piece of TLS session data D. The verified can check that D is authentically from the TLS server. From the prover’s perspective, the three-party handshake preserves the security of TLS in presence of a malicious verified.
ChainLink refer the reader to  for a full discussion of the model and formal security definitions. There are two general approaches to 2PC protocols. Garbledcircuit protocols based on Yao  encode f as a boolean circuit, an approach best-suited for bitwise operations (e.g., SHA-256). Other protocols leverage threshold secret sharing and are best suited for arithmetic operations.
The functions ChainLink compute in this paper using 2PC, though, include both bitwise and arithmetic operations. They separate them into two components, and use the optimized garbled-circuit protocol from  for the bit-wise operations and the secret-sharing based MtA protocol from  for the arithmetic operations.
Legacy credentials to anonymous credentials
Thus, DECO is the first system that allows users to convert any web-based legacy credential into an anonymous credential without server-side support  or trusted hardware . ChainLink showcase an example where a student proves her/his age is over 18 using credentials (demographic details) stored on a University website. A student can provide this proof of age to any third party, such as a state issuing a driver’s license or a hospital seeking consent for a medical test.
User credentials are often inaccessible outside a service provider’s environment. Some providers offer third-party API access via OAuth tokens, but such tokens reveal user identifiers. DECO allows users holding credentials in existing systems (what they call legacy credentials) to prove statements about them to third parties (versifier) anonymously.