fix RPC blockresults return (#5459) (#5463)

CHANGELOG_PENDING.md

@@ -29,4 +29,4 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 ### BUG FIXES
 
 - [privval] \#5441 Fix faulty ping message encoding causing nil message errors in logs (@erikgrinaker)
-
+- [rpc] \#5459 Register the interface of public keys for json encoding (@marbar3778)

crypto/encoding/codec.go

@@ -5,9 +5,15 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
+	"github.com/tendermint/tendermint/libs/json"
 	pc "github.com/tendermint/tendermint/proto/tendermint/crypto"
 )
 
+func init() {
+	json.RegisterType((*pc.PublicKey)(nil), "tendermint.crypto.PublicKey")
+	json.RegisterType((*pc.PublicKey_Ed25519)(nil), "tendermint.crypto.PublicKey_Ed25519")
+}
+
 // PubKeyToProto takes crypto.PubKey and transforms it to a protobuf Pubkey
 func PubKeyToProto(k crypto.PubKey) (pc.PublicKey, error) {
 	var kp pc.PublicKey