Decentralized Key Management¶
A decentralized key management system (DKMS) is an approach to cryptographic key management where there is no central authority. DKMS leverages the security, immutability, availability, and resiliency properties of distributed ledgers to provide highly scalable key distribution, verification, and recovery.
DKMS uses the following key types:
- Master keys: Keys that are not cryptographically protected. They are distributed manually or initially installed and protected by procedural controls and physical or electronic isolation.
- Key encrypting keys: Symmetric or public keys used for key transport or storage of other keys.
- Data keys: Used to provide cryptographic operations on user data (e.g., encryption, authentication).
The keys at one level are used to protect items at a lower level. Consequently, special measures are used to protect master keys, including severely limiting access and use, hardware protection, and providing access to the key only under shared control.
Key loss means the owner no longer controls the key and it can assume there is no further risk of compromise. For example devices unable to function due to water, electricity, breaking, fire, hardware failure, acts of God, etc.
Key compromise means that private keys and/or master keys have become or can become known either passively or actively.
In decentralized identity management, recovery is important since identity owners have no “higher authority” to turn to for recovery.
- Offline recovery uses physical media or removable digital media to store recovery keys.
- Social recovery employs entities trusted by the identity owner called “trustees” who store recovery data on an identity owners behalf—typically in the trustees own agent(s).
These methods are not exclusive and should be combined with key rotation and revocation for proper security.