types: Remove pubkey from validator hash (#2512)

* types: Remove pubkey from validator hash

* undo lock file change

* Update Spec

CHANGELOG_PENDING.md

@@ -26,6 +26,7 @@ BREAKING CHANGES:
 
 * Blockchain Protocol
   * [types] \#2459 `Vote`/`Proposal`/`Heartbeat` use amino encoding instead of JSON in `SignBytes`.
+  * [types] \#2512 Remove the pubkey field from the validator hash 
 
 * P2P Protocol
 

docs/spec/blockchain/state.md

@@ -45,7 +45,7 @@ processing transactions, like gas variables and tags - see
 ### Validator
 
 A validator is an active participant in the consensus with a public key and a voting power.
-Validator's also contain an address which is derived from the PubKey:
+Validator's also contain an address field, which is a hash digest of the PubKey.
 
 ```go
 type Validator struct {
@@ -55,6 +55,9 @@ type Validator struct {
 }
 ```
 
+When hashing the Validator struct, the pubkey is not hashed,
+because the address is already the hash of the pubkey.
+
 The `state.Validators`, `state.LastValidators`, and `state.NextValidators`, must always by sorted by validator address,
 so that there is a canonical order for computing the SimpleMerkleRoot.
 

types/validator.go

@@ -73,11 +73,9 @@ func (v *Validator) String() string {
 func (v *Validator) Hash() []byte {
 	return aminoHash(struct {
 		Address     Address
-		PubKey      crypto.PubKey
 		VotingPower int64
 	}{
 		v.Address,
-		v.PubKey,
 		v.VotingPower,
 	})
 }