diff --git a/block/tx.go b/block/tx.go
index 8739d00b..f84b4faf 100644
--- a/block/tx.go
+++ b/block/tx.go
@@ -82,7 +82,7 @@ type TxInput struct {
 	Amount    uint64    // Must not exceed account balance
 	Sequence  uint      // Must be 1 greater than the last committed TxInput
 	Signature Signature // Depends on the PubKey type and the whole Tx
-	PubKey    PubKey    // Optional, may be nil
+	PubKey    PubKey    // Must not be nil, may be PubKeyNil.
 }
 
 func (txIn *TxInput) ValidateBasic() error {
diff --git a/cmd/daemon.go b/cmd/daemon.go
index d4c38aff..9e865fde 100644
--- a/cmd/daemon.go
+++ b/cmd/daemon.go
@@ -40,7 +40,7 @@ func NewNode() *Node {
 	// Get PrivValidator
 	var privValidator *state_.PrivValidator
 	if _, err := os.Stat(config.PrivValidatorFile()); err == nil {
-		privValidator = state_.LoadPrivValidator()
+		privValidator = state_.LoadPrivValidator(config.PrivValidatorFile())
 	}
 
 	// Get PEXReactor
diff --git a/state/priv_validator.go b/state/priv_validator.go
index 8272959a..9e66e064 100644
--- a/state/priv_validator.go
+++ b/state/priv_validator.go
@@ -82,8 +82,8 @@ type PrivValidatorJSON struct {
 	LastStep   uint8
 }
 
-func LoadPrivValidator() *PrivValidator {
-	privValJSONBytes, err := ioutil.ReadFile(PrivValidatorFile())
+func LoadPrivValidator(filename string) *PrivValidator {
+	privValJSONBytes, err := ioutil.ReadFile(filename)
 	if err != nil {
 		panic(err)
 	}
@@ -112,6 +112,7 @@ func LoadPrivValidator() *PrivValidator {
 		LastHeight: privValJSON.LastHeight,
 		LastRound:  privValJSON.LastRound,
 		LastStep:   privValJSON.LastStep,
+		filename:   filename,
 	}
 	if err != nil {
 		panic(err)