diff --git a/go.mod b/go.mod
index 21d3bdc..4c3f661 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.13
 
 require (
 	github.com/mr-tron/base58 v1.1.2
-	github.com/nspcc-dev/rfc6979 v0.1.0
+	github.com/nspcc-dev/rfc6979 v0.2.0
 	github.com/pkg/errors v0.8.1
 	github.com/stretchr/testify v1.4.0
 )
diff --git a/go.sum b/go.sum
index ed5feea..d6d8473 100644
--- a/go.sum
+++ b/go.sum
@@ -2,8 +2,8 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/mr-tron/base58 v1.1.2 h1:ZEw4I2EgPKDJ2iEw0cNmLB3ROrEmkOtXIkaG7wZg+78=
 github.com/mr-tron/base58 v1.1.2/go.mod h1:BinMc/sQntlIE1frQmRFPUoPA1Zkr8VRgBdjWI2mNwc=
-github.com/nspcc-dev/rfc6979 v0.1.0 h1:Lwg7esRRoyK1Up/IN1vAef1EmvrBeMHeeEkek2fAJ6c=
-github.com/nspcc-dev/rfc6979 v0.1.0/go.mod h1:exhIh1PdpDC5vQmyEsGvc4YDM/lyQp/452QxGq/UEso=
+github.com/nspcc-dev/rfc6979 v0.2.0 h1:3e1WNxrN60/6N0DW7+UYisLeZJyfqZTNOjeV/toYvOE=
+github.com/nspcc-dev/rfc6979 v0.2.0/go.mod h1:exhIh1PdpDC5vQmyEsGvc4YDM/lyQp/452QxGq/UEso=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
diff --git a/rfc6979.go b/rfc6979.go
index b54d2e8..007198a 100644
--- a/rfc6979.go
+++ b/rfc6979.go
@@ -34,11 +34,10 @@ func hashBytesRFC6979(data []byte) []byte {
 // Note that FIPS 186-3 section 4.6 specifies that the hash should be truncated
 // to the byte-length of the subgroup. This function does not perform that.
 func SignRFC6979(key *ecdsa.PrivateKey, msg []byte) ([]byte, error) {
-	r, s, err := rfc6979.SignECDSA(key, hashBytesRFC6979(msg), sha256.New)
-	if err != nil {
-		return nil, err
+	if key == nil {
+		return nil, ErrEmptyPrivateKey
 	}
-
+	r, s := rfc6979.SignECDSA(key, hashBytesRFC6979(msg), sha256.New)
 	return append(r.Bytes(), s.Bytes()...), nil
 }
 
@@ -53,7 +52,9 @@ func decodeSignature(sig []byte) (*big.Int, *big.Int, error) {
 // VerifyRFC6979 verifies the signature of msg using the public key. It
 // return nil only if signature is valid.
 func VerifyRFC6979(key *ecdsa.PublicKey, msg, sig []byte) error {
-	if r, s, err := decodeSignature(sig); err != nil {
+	if key == nil {
+		return ErrEmptyPublicKey
+	} else if r, s, err := decodeSignature(sig); err != nil {
 		return err
 	} else if !ecdsa.Verify(key, hashBytesRFC6979(msg), r, s) {
 		return ErrWrongSignature