diff --git a/src/crypto/x509/x509.go b/src/crypto/x509/x509.go
index f572e7f2e9..6979c685a4 100644
--- a/src/crypto/x509/x509.go
+++ b/src/crypto/x509/x509.go
@@ -69,9 +69,7 @@ func marshalPublicKey(pub interface{}) (publicKeyBytes []byte, publicKeyAlgorith
 		publicKeyAlgorithm.Algorithm = oidPublicKeyRSA
 		// This is a NULL parameters value which is required by
 		// https://tools.ietf.org/html/rfc3279#section-2.3.1.
-		publicKeyAlgorithm.Parameters = asn1.RawValue{
-			Tag: 5,
-		}
+		publicKeyAlgorithm.Parameters = asn1.NullRawValue
 	case *ecdsa.PublicKey:
 		publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
 		oid, ok := oidFromNamedCurve(pub.Curve)
@@ -355,10 +353,8 @@ func rsaPSSParameters(hashFunc crypto.Hash) asn1.RawValue {
 
 	params := pssParameters{
 		Hash: pkix.AlgorithmIdentifier{
-			Algorithm: hashOID,
-			Parameters: asn1.RawValue{
-				Tag: 5, /* ASN.1 NULL */
-			},
+			Algorithm:  hashOID,
+			Parameters: asn1.NullRawValue,
 		},
 		MGF: pkix.AlgorithmIdentifier{
 			Algorithm: oidMGF1,
@@ -368,10 +364,8 @@ func rsaPSSParameters(hashFunc crypto.Hash) asn1.RawValue {
 	}
 
 	mgf1Params := pkix.AlgorithmIdentifier{
-		Algorithm: hashOID,
-		Parameters: asn1.RawValue{
-			Tag: 5, /* ASN.1 NULL */
-		},
+		Algorithm:  hashOID,
+		Parameters: asn1.NullRawValue,
 	}
 
 	var err error
@@ -418,11 +412,10 @@ func getSignatureAlgorithmFromAI(ai pkix.AlgorithmIdentifier) SignatureAlgorithm
 	// https://tools.ietf.org/html/rfc3447#section-8.1), that the
 	// salt length matches the hash length, and that the trailer
 	// field has the default value.
-	asn1NULL := []byte{0x05, 0x00}
-	if !bytes.Equal(params.Hash.Parameters.FullBytes, asn1NULL) ||
+	if !bytes.Equal(params.Hash.Parameters.FullBytes, asn1.NullBytes) ||
 		!params.MGF.Algorithm.Equal(oidMGF1) ||
 		!mgf1HashFunc.Algorithm.Equal(params.Hash.Algorithm) ||
-		!bytes.Equal(mgf1HashFunc.Parameters.FullBytes, asn1NULL) ||
+		!bytes.Equal(mgf1HashFunc.Parameters.FullBytes, asn1.NullBytes) ||
 		params.TrailerField != 1 {
 		return UnknownSignatureAlgorithm
 	}
@@ -928,16 +921,13 @@ type distributionPointName struct {
 	RelativeName pkix.RDNSequence `asn1:"optional,tag:1"`
 }
 
-// asn1Null is the ASN.1 encoding of a NULL value.
-var asn1Null = []byte{5, 0}
-
 func parsePublicKey(algo PublicKeyAlgorithm, keyData *publicKeyInfo) (interface{}, error) {
 	asn1Data := keyData.PublicKey.RightAlign()
 	switch algo {
 	case RSA:
 		// RSA public keys must have a NULL in the parameters
 		// (https://tools.ietf.org/html/rfc3279#section-2.3.1).
-		if !bytes.Equal(keyData.Algorithm.Parameters.FullBytes, asn1Null) {
+		if !bytes.Equal(keyData.Algorithm.Parameters.FullBytes, asn1.NullBytes) {
 			return nil, errors.New("x509: RSA key missing NULL parameters")
 		}
 
@@ -1650,9 +1640,7 @@ func signingParamsForPublicKey(pub interface{}, requestedSigAlgo SignatureAlgori
 		pubType = RSA
 		hashFunc = crypto.SHA256
 		sigAlgo.Algorithm = oidSignatureSHA256WithRSA
-		sigAlgo.Parameters = asn1.RawValue{
-			Tag: 5,
-		}
+		sigAlgo.Parameters = asn1.NullRawValue
 
 	case *ecdsa.PublicKey:
 		pubType = ECDSA
diff --git a/src/encoding/asn1/asn1.go b/src/encoding/asn1/asn1.go
index 65f018d014..b8e2770596 100644
--- a/src/encoding/asn1/asn1.go
+++ b/src/encoding/asn1/asn1.go
@@ -207,6 +207,14 @@ func parseBitString(bytes []byte) (ret BitString, err error) {
 	return
 }
 
+// NULL
+
+// NullRawValue is a RawValue with its Tag set to the ASN.1 NULL type tag (5).
+var NullRawValue = RawValue{Tag: TagNull}
+
+// NullBytes contains bytes representing the DER-encoded ASN.1 NULL type.
+var NullBytes = []byte{TagNull, 0}
+
 // OBJECT IDENTIFIER
 
 // An ObjectIdentifier represents an ASN.1 OBJECT IDENTIFIER.
diff --git a/src/encoding/asn1/asn1_test.go b/src/encoding/asn1/asn1_test.go
index 2dd799f236..c9eda4069d 100644
--- a/src/encoding/asn1/asn1_test.go
+++ b/src/encoding/asn1/asn1_test.go
@@ -479,6 +479,7 @@ var unmarshalTestData = []struct {
 	out interface{}
 }{
 	{[]byte{0x02, 0x01, 0x42}, newInt(0x42)},
+	{[]byte{0x05, 0x00}, &RawValue{0, 5, false, []byte{}, []byte{0x05, 0x00}}},
 	{[]byte{0x30, 0x08, 0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d}, &TestObjectIdentifierStruct{[]int{1, 2, 840, 113549}}},
 	{[]byte{0x03, 0x04, 0x06, 0x6e, 0x5d, 0xc0}, &BitString{[]byte{110, 93, 192}, 18}},
 	{[]byte{0x30, 0x09, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x01, 0x03}, &[]int{1, 2, 3}},
@@ -1007,3 +1008,28 @@ func TestUnexportedStructField(t *testing.T) {
 		t.Errorf("got %v, want %v", err, want)
 	}
 }
+
+func TestNull(t *testing.T) {
+	marshaled, err := Marshal(NullRawValue)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(NullBytes, marshaled) {
+		t.Errorf("Expected Marshal of NullRawValue to yeild %x, got %x", NullBytes, marshaled)
+	}
+
+	unmarshaled := RawValue{}
+	if _, err := Unmarshal(NullBytes, &unmarshaled); err != nil {
+		t.Fatal(err)
+	}
+
+	unmarshaled.FullBytes = NullRawValue.FullBytes
+	if len(unmarshaled.Bytes) == 0 {
+		// DeepEqual considers a nil slice and an empty slice to be different.
+		unmarshaled.Bytes = NullRawValue.Bytes
+	}
+
+	if !reflect.DeepEqual(NullRawValue, unmarshaled) {
+		t.Errorf("Expected Unmarshal of NullBytes to yield %v, got %v", NullRawValue, unmarshaled)
+	}
+}
diff --git a/src/encoding/asn1/common.go b/src/encoding/asn1/common.go
index 0695180827..cd93b27ecb 100644
--- a/src/encoding/asn1/common.go
+++ b/src/encoding/asn1/common.go
@@ -24,6 +24,7 @@ const (
 	TagInteger         = 2
 	TagBitString       = 3
 	TagOctetString     = 4
+	TagNull            = 5
 	TagOID             = 6
 	TagEnum            = 10
 	TagUTF8String      = 12