2 The basic building blocks of SSI

by Drummond Reed, Rieks Joosten, and Oskar van Deventer

As we explained in chapter 1, SSI is relatively new, having only emerged onto the Internet stage in 2016. At one level, SSI is a set of principles about how identity and personal data control should work across digital networks. At another level, SSI is a set of technologies that build upon core concepts in identity management, distributed computing, blockchain or Distributed Ledger Technology (DLT), and cryptography.

In many cases these core concepts have been established for decades. What’s new is how they are put together to create a new model for digital identity management. The purpose of this chapter is to quickly familiarize you with these seven basic building blocks from a conceptual and technical point of view before we show how they are applied to different example scenarios in chapter 3.

  1. Verifiable credentials (aka digital credentials)
  2. Issuers, holders, and verifiers
  3. Digital wallets
  4. Digital agents and hubs
  5. Decentralized identifiers (DIDs)
  6. Blockchains
  7. Governance frameworks (aka trust frameworks)

Note that we will go much deeper into these building blocks in Part 2: SSI Architecture.

2.1       Verifiable credentials

In chapter 1 we summarized that the essence of decentralized identity is “to move the utility and portability of physical identity credentials to our digital devices.” This is why the concept at the very heart of SSI is verifiable credentials.

2.2       Issuers, holders, and verifiers

2.3       Digital wallets

2.4       Digital agents and hubs

2.5       Decentralized Identifiers (DIDs)

2.6       Blockchains

2.7       Governance frameworks