diff --git a/chain/consensus/filcns/filecoin.go b/chain/consensus/filcns/filecoin.go
index c163c9c3b..a698abd47 100644
--- a/chain/consensus/filcns/filecoin.go
+++ b/chain/consensus/filcns/filecoin.go
@@ -577,7 +577,7 @@ func (filec *FilecoinEC) checkBlockMessages(ctx context.Context, b *types.FullBl
 
 	smArr := blockadt.MakeEmptyArray(tmpstore)
 	for i, m := range b.SecpkMessages {
-		if !filec.ValidateSecpkSigType(nv, m.Signature.Type) {
+		if nv >= network.Version14 && !chain.IsValidSecpkSigType(nv, m.Signature.Type) {
 			return xerrors.Errorf("block had invalid signed message at index %d: %w", i, err)
 		}
 
@@ -901,17 +901,4 @@ func (filec *FilecoinEC) isChainNearSynced() bool {
 	return build.Clock.Since(timestampTime) < 6*time.Hour
 }
 
-// ValidateSecpkSigType checks that a signature type is valid for the network
-// version, for a "secpk" message.
-func (filec *FilecoinEC) ValidateSecpkSigType(nv network.Version, typ crypto.SigType) bool {
-	switch {
-	case nv < network.Version14:
-		return true // no check for signature type before nv14
-	case nv >= network.Version14 && nv < network.Version18:
-		return typ == crypto.SigTypeSecp256k1
-	default:
-		return typ == crypto.SigTypeSecp256k1 || typ == crypto.SigTypeDelegated
-	}
-}
-
 var _ consensus.Consensus = &FilecoinEC{}
diff --git a/chain/consensus/filcns/mine.go b/chain/consensus/filcns/mine.go
index 992453178..b80937c4b 100644
--- a/chain/consensus/filcns/mine.go
+++ b/chain/consensus/filcns/mine.go
@@ -3,6 +3,7 @@ package filcns
 import (
 	"context"
 
+	"github.com/filecoin-project/lotus/chain"
 	"github.com/ipfs/go-cid"
 	"golang.org/x/xerrors"
 
@@ -54,6 +55,7 @@ func (filec *FilecoinEC) CreateBlock(ctx context.Context, w api.Wallet, bt *api.
 
 	var blsMsgCids, secpkMsgCids []cid.Cid
 	var blsSigs []crypto.Signature
+	nv := filec.sm.GetNetworkVersion(ctx, bt.Epoch)
 	for _, msg := range bt.Messages {
 		if msg.Signature.Type == crypto.SigTypeBLS {
 			blsSigs = append(blsSigs, msg.Signature)
@@ -65,7 +67,7 @@ func (filec *FilecoinEC) CreateBlock(ctx context.Context, w api.Wallet, bt *api.
 			}
 
 			blsMsgCids = append(blsMsgCids, c)
-		} else if msg.Signature.Type == crypto.SigTypeSecp256k1 || msg.Signature.Type == crypto.SigTypeDelegated {
+		} else if chain.IsValidSecpkSigType(nv, msg.Signature.Type) {
 			c, err := filec.sm.ChainStore().PutMessage(ctx, msg)
 			if err != nil {
 				return nil, err
diff --git a/chain/signatures.go b/chain/signatures.go
index 4558dd1b3..e09aa7079 100644
--- a/chain/signatures.go
+++ b/chain/signatures.go
@@ -3,6 +3,7 @@ package chain
 import (
 	"github.com/filecoin-project/go-address"
 	"github.com/filecoin-project/go-state-types/crypto"
+	"github.com/filecoin-project/go-state-types/network"
 	"github.com/filecoin-project/lotus/chain/types"
 	"github.com/filecoin-project/lotus/chain/types/ethtypes"
 	"github.com/filecoin-project/lotus/lib/sigs"
@@ -36,3 +37,14 @@ func AuthenticateMessage(msg *types.SignedMessage, signer address.Address) error
 	}
 	return nil
 }
+
+// IsValidSecpkSigType checks that a signature type is valid for the network
+// version, for a "secpk" message.
+func IsValidSecpkSigType(nv network.Version, typ crypto.SigType) bool {
+	switch {
+	case nv < network.Version18:
+		return typ == crypto.SigTypeSecp256k1
+	default:
+		return typ == crypto.SigTypeSecp256k1 || typ == crypto.SigTypeDelegated
+	}
+}