Addressable Entities
What is an Addressable Entity?
Casper 2.0 introduces the concept of an AddressableEntity that will supplant the individual Account and Contract types for any new usage.
The merger of the Account and Contract concepts will allow for some new possibilities that were previously not available individually to Accounts or Contracts. Within the context for any given AddressableEntity, the EntityType will identify if it is an Account, a user-deployed SmartContract, or a System contract such as Mint or HandlePayment.
This EntityType will dictate what the addressable entity can and cannot do.
Account
An addressable entity marked as an Account will behave in much the same way as a traditional legacy account on a Casper network. It will have an associated key pair of a PublicKey and a secret key, and an AccountHash derived from the public key. There is also an associated main purse.
A legacy account will automatically migrate to an addressable entity when it interacts with the network, with no action necessary on the user side. Their key pair will continue functioning as it did prior to the migration. Further, their main purse will remain the same.
SmartContract
An addressable entity marked as a SmartContract will have the same functionality as a legacy contract, but with several new features. The SmartContract now possesses a main purse, and may have associated keys and action thresholds that behave in the same way as an account. More information on multi-signature management, associated keys, and action thresholds can be found here.
System
As part of the migration to Casper 2.0, system contracts (Mint, Auction and HandlePayment) will migrate to a special type of addressable entity with the EntityType of System. The StandardPayment system contract will be pruned away.