10 Decentralized key management
Chapter 9 covered the overall topic of SSI digital wallets and agents. However the function at the very core of digital wallets—cryptographic key management—is deep enough to merit its own chapter. Although thousands of papers and dozens of books have been written on the subject of key management, for this chapter on decentralized key management we called on Dr. Sam Smith, who is not only one of the most prolific thinkers and authors in SSI, but the inventor of Key Event Receipt Infrastructure (KERI), covered in the final section of this chapter. Sam received his Ph.D. in Electrical and Computer Engineering from Brigham Young University in 1991, spent 10 years at Florida Atlantic University reaching full professor status, then retired to become a full-time entrepreneur and strategic consultant. He has over 100 refereed publications in the areas of machine learning, AI, autonomous vehicle systems, automated reasoning, blockchains, and decentralized systems.
Chapter 9 began with this overarching definition of digital wallets:
A digital wallet consists of software (and optionally hardware) that enables the controller of the wallet to generate, store, manage, and protect cryptographic keys, secrets, and other sensitive private data.
We followed that by saying that a digital wallet is the nexus of control for every actor in SSI. The essence of that control is key management. As the Wikipedia article on the subject states:[1]