VERSION               |  2 +-
 gost3410/2012_test.go |  2 ++
 gost3410/curve.go     | 10 +++++++++-
 gost3410/params.go    |  9 +++++++++
 gost3410/vko.go       |  1 +
 install.texi          |  2 +-
 news.texi             |  5 +++++

diff --git a/VERSION b/VERSION
index 976c3ef46cb8b05ad32a9279ef35015e87cbc2cb2c059307536ff2c458ca7167..34f9ca98f52526a7a6977302541789baab393bcedb5229c7bdac2f6d061109df 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.2.4
+4.3.0
diff --git a/gost3410/2012_test.go b/gost3410/2012_test.go
index f8e0d8d8ec93d0404ba7d42931537bb3170e88c701f24e059eb2112a1ea48c48..109fa349a7156d924be54c3d159dceef406e6faecf46cd7c113cf17c206a07e0 100644
--- a/gost3410/2012_test.go
+++ b/gost3410/2012_test.go
@@ -126,6 +126,7 @@ 			0x6D, 0xBB, 0x92, 0xCB, 0x1A, 0xDD, 0x37, 0x1E,
 		}),
 		nil,
 		nil,
+		nil,
 	)
 	if err != nil {
 		t.FailNow()
@@ -320,6 +321,7 @@ 		bytes2big(a),
 		bytes2big(b),
 		bytes2big(x),
 		bytes2big(y),
+		nil,
 		nil,
 		nil,
 	)
diff --git a/gost3410/curve.go b/gost3410/curve.go
index e6df87b217b068c0b2609ba3b6cf357e83e1ee85889262eeb304082e32a1fca8..bc010b432bf63d8d426a9c7a63b10034273b9bbeede2d82107e21e427ee5bb16 100644
--- a/gost3410/curve.go
+++ b/gost3410/curve.go
@@ -25,6 +25,7 @@ 	zero    *big.Int = big.NewInt(0)
 	bigInt1 *big.Int = big.NewInt(1)
 	bigInt2 *big.Int = big.NewInt(2)
 	bigInt3 *big.Int = big.NewInt(3)
+	bigInt4 *big.Int = big.NewInt(4)
 )
 
 type Curve struct {
@@ -32,6 +33,8 @@ 	Name string // Just simple identifier
 
 	P *big.Int // Characteristic of the underlying prime field
 	Q *big.Int // Elliptic curve subgroup order
+
+	Co *big.Int // Cofactor
 
 	// Equation coefficients of the elliptic curve in canonical form
 	A *big.Int
@@ -55,7 +58,7 @@ 	edS *big.Int
 	edT *big.Int
 }
 
-func NewCurve(p, q, a, b, x, y, e, d *big.Int) (*Curve, error) {
+func NewCurve(p, q, a, b, x, y, e, d, co *big.Int) (*Curve, error) {
 	c := Curve{
 		Name: "unknown",
 		P:    p,
@@ -84,6 +87,11 @@ 	}
 	if e != nil && d != nil {
 		c.E = e
 		c.D = d
+	}
+	if co == nil {
+		c.Co = bigInt1
+	} else {
+		c.Co = co
 	}
 	return &c, nil
 }
diff --git a/gost3410/params.go b/gost3410/params.go
index 990f2ce5ba894f242bf3b4511365248e8765713f5b05cd77f54512e292c2d25b..3142c34785973c04623a2c950f328194165b107b8cddf3c61a8bfb78b2febba5 100644
--- a/gost3410/params.go
+++ b/gost3410/params.go
@@ -61,6 +61,7 @@ 				0x44, 0x0b, 0xed, 0xc8, 0xcc, 0xb6, 0xb2, 0x2c,
 			}),
 			nil,
 			nil,
+			nil,
 		)
 		if err != nil {
 			panic(err)
@@ -107,6 +108,7 @@ 				0xBD, 0x63, 0x16, 0x03, 0x0E, 0x16, 0xD1, 0x9C,
 				0x85, 0xC9, 0x7F, 0x0A, 0x9C, 0xA2, 0x67, 0x12,
 				0x2B, 0x96, 0xAB, 0xBC, 0xEA, 0x7E, 0x8F, 0xC8,
 			}),
+			nil,
 			nil,
 			nil,
 		)
@@ -155,6 +157,7 @@ 				0x27, 0xDF, 0x50, 0x5A, 0x45, 0x3F, 0x2B, 0x76,
 				0x35, 0x29, 0x4F, 0x2D, 0xDF, 0x23, 0xE3, 0xB1,
 				0x22, 0xAC, 0xC9, 0x9C, 0x9E, 0x9F, 0x1E, 0x14,
 			}),
+			nil,
 			nil,
 			nil,
 		)
@@ -205,6 +208,7 @@ 				0x74, 0x4B, 0xF8, 0xD7, 0x17, 0x71, 0x7E, 0xFC,
 			}),
 			nil,
 			nil,
+			nil,
 		)
 		if err != nil {
 			panic(err)
@@ -251,6 +255,7 @@ 				0x3C, 0xBF, 0x37, 0x83, 0xCD, 0x08, 0xC0, 0xEE,
 				0x4D, 0x4D, 0xC4, 0x40, 0xD4, 0x64, 0x1A, 0x8F,
 				0x36, 0x6E, 0x55, 0x0D, 0xFD, 0xB3, 0xBB, 0x67,
 			}),
+			nil,
 			nil,
 			nil,
 		)
@@ -318,6 +323,7 @@ 				0x57, 0x8B, 0xC3, 0x9C, 0xFA, 0xD5, 0x18, 0x13,
 				0x2B, 0x9D, 0xF6, 0x28, 0x97, 0x00, 0x9A, 0xF7,
 				0xE5, 0x22, 0xC3, 0x2D, 0x6D, 0xC7, 0xBF, 0xFB,
 			}),
+			bigInt4,
 		)
 		if err != nil {
 			panic(err)
@@ -406,6 +412,7 @@ 				0x3D, 0x75, 0xE6, 0xA5, 0x0E, 0x3A, 0x41, 0xE9,
 				0x80, 0x28, 0xFE, 0x5F, 0xC2, 0x35, 0xF5, 0xB8,
 				0x89, 0xA5, 0x89, 0xCB, 0x52, 0x15, 0xF2, 0xA4,
 			}),
+			nil,
 			nil,
 			nil,
 		)
@@ -480,6 +487,7 @@ 				0x7E, 0x21, 0x34, 0x07, 0x80, 0xFE, 0x41, 0xBD,
 			}),
 			nil,
 			nil,
+			nil,
 		)
 		if err != nil {
 			panic(err)
@@ -561,6 +569,7 @@ 				0x04, 0xE2, 0xCE, 0x43, 0xE7, 0x9E, 0x36, 0x9E,
 				0x91, 0xA0, 0xCF, 0xC2, 0xBC, 0x2A, 0x22, 0xB4,
 				0xCA, 0x30, 0x2D, 0xBB, 0x33, 0xEE, 0x75, 0x50,
 			}),
+			bigInt4,
 		)
 		if err != nil {
 			panic(err)
diff --git a/gost3410/vko.go b/gost3410/vko.go
index e3cc02496c02b2a192dc56c918478819a36527bb773b2123df45759ce12a53cd..d06793e4d68938c73dc226eb52cc48a4148bb254d14bf1525341c8b79f2f6934 100644
--- a/gost3410/vko.go
+++ b/gost3410/vko.go
@@ -24,6 +24,7 @@ 	keyX, keyY, err := prv.C.Exp(prv.Key, pub.X, pub.Y)
 	if err != nil {
 		return nil, err
 	}
+	ukm = ukm.Mul(ukm, prv.C.Co)
 	if ukm.Cmp(bigInt1) != 0 {
 		keyX, keyY, err = prv.C.Exp(ukm, keyX, keyY)
 		if err != nil {
diff --git a/install.texi b/install.texi
index a6f5b4381850f44285b7f473c306670fe0ebc5f2978e8fc0ef84c32f79a29054..490c133aa30e43bf8dca113b9059f1204882dbcde8d3d6997ed575af18f2b04e 100644
--- a/install.texi
+++ b/install.texi
@@ -1,7 +1,7 @@
 @node Download
 @unnumbered Download
 
-@set VERSION 4.2.4
+@set VERSION 4.3.0
 
 Preferable way is to download tarball with the signature from
 website and, for example, run tests with benchmarks:
diff --git a/news.texi b/news.texi
index f748611ab59327628b15d6effef18acd6e8ff62251208c775155f909619ccc30..bf119451e415b33abc849a9462b6265de79c3656abc4dcc5616a822d0049a1e6 100644
--- a/news.texi
+++ b/news.texi
@@ -3,6 +3,11 @@ @unnumbered News
 
 @table @strong
 
+@anchor{Release 4.3.0}
+@item 4.3.0
+    @strong{Fixed} nasty bug with Edwards curves using in 34.10-VKO
+    functions: curve's cofactor has not been used.
+
 @anchor{Release 4.2.4}
 @item 4.2.4
     @code{gost3410.PrivateKeyReverseDigest} reversed digests and