# Introduction The proliferation of cryptographic protocols such as Transport Layer Security (TLS) transformed the concept of security on internet from a luxury affored by few into a commodity. With TLS, an average internet user is able to exchange encrypted messages online, use credit cards online, or download files; all without the fear of censorship or compromising his or her computer system. However, TLS's usefulness is limited outside the boundaries of simple but familiar server-client architectures. With SSL certificates, it is possible to protect users by providing identities to service providers and ways for users to authenticate them. However, as more and more devices and services are going online. authenticating only service providers is simply not enough; the days of only servers with identities are over, as every user, every device needs a certificate of its own. We need identities for not only social network services, but digital door locks, refrigerators, and automobiles. We also need new ways for devices and services to identify and authenticate each other without human interactions. Simply put, existing Public Key Infrastructure (PKI) for providing identities to web services is not good enough. Even Google is developing new technologies such as Certificate Transparency to supplement the shortcomings of the PKI technologies. Most of limitations of PKI systems come from the centralized nature of PKI providers, and distributed ledger technologies such as blockchain are expected to play a huge role in supplementing and replacing the limited PKI systems. Blocko's OpenKeyChain is intended to be a robust real life implementation of such a PKI system based on blockchain technology OpenKeyChain enables developers and users to deploy new PKIs without huge investments by leveraging the existing public blockchain infrastructure; anyone can register and manage certificates for devices and services, and sign or encrypt messages between parties even without TLS involved. OpenKeyChain is an open standard allowing others to review and extend its ideas. Blocko's Coinstack SDKs include reference implementations of OpenKeyChain; applications on all platforms (servers, clients, and web browers) are supported. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://blocko-1.gitbook.io/openkeychain-spec/master.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.