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 emerged onto the Internet stage in 2015. 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 paradigm for digital identity management. The purpose of this chapter is to quickly familiarize you with these 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.
This chapter covers seven basic building blocks:
- Verifiable credentials (aka digital credentials)
- Issuers, holders, and verifiers
- Digital wallets
- Digital agents and hubs
- Decentralized identifiers (DIDs)
- Blockchains
- Governance frameworks (aka trust frameworks)
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.