diff --git a/go.mod b/go.mod
index eac194fee..2110c6fcc 100644
--- a/go.mod
+++ b/go.mod
@@ -7,8 +7,8 @@ require (
 	github.com/go-redis/redis v6.10.2+incompatible
 	github.com/go-yaml/yaml v2.1.0+incompatible
 	github.com/mr-tron/base58 v1.1.2
-	github.com/nspcc-dev/dbft v0.0.0-20200113100648-b3578fc15d82
-	github.com/nspcc-dev/rfc6979 v0.1.0
+	github.com/nspcc-dev/dbft v0.0.0-20200116150450-80b3f6f0dff8
+	github.com/nspcc-dev/rfc6979 v0.2.0
 	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v1.2.1
 	github.com/stretchr/testify v1.4.0
diff --git a/go.sum b/go.sum
index 3223b56e9..5db146de9 100644
--- a/go.sum
+++ b/go.sum
@@ -94,12 +94,16 @@ github.com/nspcc-dev/dbft v0.0.0-20191205084618-dacb1a30c254 h1:A4OkQDQOSPsJF8qU
 github.com/nspcc-dev/dbft v0.0.0-20191205084618-dacb1a30c254/go.mod h1:w1Ln2aT+dBlPhLnuZhBV+DfPEdS2CHWWLp5JTScY3bw=
 github.com/nspcc-dev/dbft v0.0.0-20191209120240-0d6b7568d9ae h1:T5V1QANlNMKun0EPB3eqg2PTXG4rmLhzDyEiV63kdB0=
 github.com/nspcc-dev/dbft v0.0.0-20191209120240-0d6b7568d9ae/go.mod h1:3FjXOoHmA51EGfb5GS/HOv7VdmngNRTssSeQ729dvGY=
-github.com/nspcc-dev/dbft v0.0.0-20200113100648-b3578fc15d82 h1:jwFLk2NKgyUbmJGlZsn3qIjoRqUkKajXb45ZuWbvkT4=
-github.com/nspcc-dev/dbft v0.0.0-20200113100648-b3578fc15d82/go.mod h1:IyIyVYKfi41kAlGWqicz9G8Iyni71Resuhtd9Y5ujJM=
+github.com/nspcc-dev/dbft v0.0.0-20200116150450-80b3f6f0dff8 h1:WjfnKH75ncU5iySB6ooTsbg2P0q1iQoecTN4gHIuEbs=
+github.com/nspcc-dev/dbft v0.0.0-20200116150450-80b3f6f0dff8/go.mod h1:/YFK+XOxxg0Bfm6P92lY5eDSLYfp06XOdL8KAVgXjVk=
 github.com/nspcc-dev/neofs-crypto v0.2.0 h1:ftN+59WqxSWz/RCgXYOfhmltOOqU+udsNQSvN6wkFck=
 github.com/nspcc-dev/neofs-crypto v0.2.0/go.mod h1:F/96fUzPM3wR+UGsPi3faVNmFlA9KAEAUQR7dMxZmNA=
+github.com/nspcc-dev/neofs-crypto v0.2.3 h1:aca3X2aly92ENRbFK+kH6Hd+J9EQ4Eu6XMVoITSIKtc=
+github.com/nspcc-dev/neofs-crypto v0.2.3/go.mod h1:8w16GEJbH6791ktVqHN9YRNH3s9BEEKYxGhlFnp0cDw=
 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/onsi/ginkgo v1.6.0 h1:Ix8l273rp3QzYgXSR+c8d1fTG7UPgYkOSELPhiY/YGw=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.10.3 h1:OoxbjfXVZyod1fmWYhI7SEyaD8B00ynP3T+D5GiyHOY=
diff --git a/pkg/crypto/keys/private_key.go b/pkg/crypto/keys/private_key.go
index 924f1bebe..cca174d78 100644
--- a/pkg/crypto/keys/private_key.go
+++ b/pkg/crypto/keys/private_key.go
@@ -111,10 +111,7 @@ func (p *PrivateKey) Sign(data []byte) ([]byte, error) {
 		digest     = sha256.Sum256(data)
 	)
 
-	r, s, err := rfc6979.SignECDSA(privateKey, digest[:], sha256.New)
-	if err != nil {
-		return nil, err
-	}
+	r, s := rfc6979.SignECDSA(privateKey, digest[:], sha256.New)
 
 	params := privateKey.Curve.Params()
 	curveOrderByteSize := params.P.BitLen() / 8