Arthur C. Clarke said, “Any sufficiently advanced technology is indistinguishable from magic.” In part 1, we introduced the basic building blocks of SSI at a level comfortable for non-technologists. In part 2, we go behind the curtain to look much more deeply at these building blocks and see how they are assembled to accomplish the “magic” of SSI:

• Chapter 5 gives a big-picture overview of SSI architecture and some of the key design choices facing SSI architects.

• Chapter 6 explains why SSI is “cryptography all the way down” and introduces the innovations in cryptography that make SSI possible.

• Chapter 7 is a mini-textbook on the star of the SSI show: verifiable credentials (VCs). This is the only chapter with code snippets: examples of the JSON and JSON-LD data structures at the heart of the W3C Verifiable Credentials Data Model 1.0 specification.

• Chapter 8 is a deep dive into the other foundational open standard for SSI: the W3C Decentralized Identifiers (DID) Core Specification. It includes an in-depth analysis of how DIDs solve the hardest problem in conventional public key infrastructure (PKI).

• Chapter 9 tackles the two main tools in the hands of SSI users—digital wallets and digital agents—and covers lessons learned from the first generation of implementers.

• Chapter 10 goes even deeper into the very heart of SSI: decentralized cryptographic key management. It includes a full analysis of the most significant innovation in this space: Key Event Receipt Infrastructure (KERI).

• Chapter 11 explains why all of this fabulous new technology will produce real-world benefits only if it is harnessed to a different kind of tool for trust: governance frameworks (aka trust frameworks) that provide the “glue” to business, legal, and social policies.