Your validator key, much like your ‘normal’ Eth1 key, uses elliptic-curve cryptography. However, in Ethereum 2.0, your keys have additional functionalities, and require different parameters when being created, leveraging the Boneh-Lynn-Shacham (=BLS) signature processes.
Breakdown of Ethereum 2.0 Keys
In Ethereum 1.0, users have a single private key to access their funds. Ethereum 2.0 requires two different keypairs. Validator keys and withdrawal keys.
The Validator Key
The validator signing key consists of two elements:
- Validator private key
- Validator public key
The role of the validator private key is to actively sign on-chain (Eth2) duties, namely attestations and block proposals.
The validator public key is included in the deposit data which allows Eth2 to identify and associate between the validator and the ETH funds.
The Withdrawal Key
The withdrawal key is required to move (or withdraw) the validator balance.
Although being developed and already accounted for, this ability will only be made available in later phases of Eth2 (expected in Q1 of 2021).
Much like the validator key, the withdrawal key also consist of two components:
- Withdrawal private key
- Withdrawal public key
Losing this key means losing access to the validator, and the entirety of the ETH balance at stake. A validator is still able to propose and attest if a withdrawal key is lost; however the ETH at stake is not accessible for withdrawal or transfer without this key.