diff --git a/pkg/network/payload/inventory.go b/pkg/network/payload/inventory.go
new file mode 100644
index 000000000..ca508b4bb
--- /dev/null
+++ b/pkg/network/payload/inventory.go
@@ -0,0 +1,63 @@
+package payload
+
+import (
+	"bytes"
+	"encoding/binary"
+
+	. "github.com/anthdm/neo-go/pkg/util"
+)
+
+// The node can broadcast the object information it owns by this message.
+// The message can be sent automatically or can be used to answer getbloks messages.
+
+// InventoryType is the type of an object in the Inventory message.
+type InventoryType uint8
+
+// String implements the Stringer interface.
+func (i InventoryType) String() string {
+	switch i {
+	case 0x01:
+		return "block"
+	case 0x02:
+		return "TX"
+	case 0xe0:
+		return "consensus"
+	default:
+		return "unknown inventory type"
+	}
+}
+
+// List of valid InventoryTypes.
+const (
+	BlockType     InventoryType = 0x01 // 1
+	TXType                      = 0x02 // 2
+	ConsensusType               = 0xe0 // 224
+)
+
+// Inventory payload
+type Inventory struct {
+	// Type if the object hash.
+	Type InventoryType
+	// The hash of the object (uint256).
+	Hash Uint256
+}
+
+// UnmarshalBinary implements the Payloader interface.
+func (p *Inventory) UnmarshalBinary(b []byte) error {
+	// TODO: what byte is [1:2] ?
+	// We have 1 byte for the type which is uint8 and 32 for the hash.
+	// There is 1 byte left over.
+	binary.Read(bytes.NewReader(b), binary.LittleEndian, &p.Type)
+	p.Hash.UnmarshalBinary(b[2:len(b)])
+	return nil
+}
+
+// MarshalBinary implements the Payloader interface.
+func (p *Inventory) MarshalBinary() ([]byte, error) {
+	return nil, nil
+}
+
+// Size implements the Payloader interface.
+func (p *Inventory) Size() uint32 {
+	return 1 + 1 + 32 // ?
+}
diff --git a/pkg/util/random.go b/pkg/util/random.go
new file mode 100644
index 000000000..0ea02d4d9
--- /dev/null
+++ b/pkg/util/random.go
@@ -0,0 +1,16 @@
+package util
+
+import (
+	"math/rand"
+	"time"
+)
+
+// RandUint32 return a random number between min and max.
+func RandUint32(min, max int) uint32 {
+	n := min + rand.Intn(max-min)
+	return uint32(n)
+}
+
+func init() {
+	rand.Seed(time.Now().UTC().UnixNano())
+}
diff --git a/pkg/util/uint256.go b/pkg/util/uint256.go
new file mode 100644
index 000000000..d82e19877
--- /dev/null
+++ b/pkg/util/uint256.go
@@ -0,0 +1,46 @@
+package util
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+)
+
+// Uint256 ...
+type Uint256 [32]uint8
+
+// Uint256FromBytes return an Uint256 from a byte slice.
+func Uint256FromBytes(b []byte) Uint256 {
+	if len(b) != 32 {
+		err := fmt.Sprintf("%d does not match the size of Uint256 (32 bytes)", len(b))
+		panic(err)
+	}
+
+	var val [32]uint8
+	for i := 0; i < 32; i++ {
+		val[i] = b[i]
+	}
+
+	return Uint256(val)
+}
+
+// UnmarshalBinary implements the Binary Unmarshaler interface.
+func (u *Uint256) UnmarshalBinary(b []byte) error {
+	r := bytes.NewReader(b)
+	binary.Read(r, binary.LittleEndian, u)
+	return nil
+}
+
+// ToSlice return a byte slice of u.
+func (u Uint256) ToSlice() []byte {
+	b := make([]byte, 32)
+	for i := 0; i < 32; i++ {
+		b[i] = byte(u[i])
+	}
+	return b
+}
+
+func (u Uint256) String() string {
+	return hex.EncodeToString(u.ToSlice())
+}
diff --git a/pkg/util/uint256_test.go b/pkg/util/uint256_test.go
new file mode 100644
index 000000000..124e9f600
--- /dev/null
+++ b/pkg/util/uint256_test.go
@@ -0,0 +1,8 @@
+package util
+
+import (
+	"testing"
+)
+
+func TestUint256(t *testing.T) {
+}