*: remove duplicate functions producing verification script

Drop wif.GetVerificationScript(), drop
smartcontract.CreateSignatureRedeemScript(), add GetVerificationScript()
directly to the PublicKey and use it everywhere.

pkg/consensus/payload.go

@@ -7,7 +7,6 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/io"
-	"github.com/CityOfZion/neo-go/pkg/smartcontract"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/CityOfZion/neo-go/pkg/vm"
 	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
@@ -189,13 +188,8 @@ func (p *Payload) Sign(key *privateKey) error {
 		return err
 	}
 
-	verif, err := smartcontract.CreateSignatureRedeemScript(key.PublicKey())
-	if err != nil {
-		return err
-	}
-
 	p.Witness.InvocationScript = append([]byte{byte(opcode.PUSHBYTES64)}, sig...)
-	p.Witness.VerificationScript = verif
+	p.Witness.VerificationScript = key.PublicKey().GetVerificationScript()
 
 	return nil
 }

pkg/core/interop_system.go

@@ -8,7 +8,6 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
-	"github.com/CityOfZion/neo-go/pkg/smartcontract"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/CityOfZion/neo-go/pkg/vm"
 	gherr "github.com/pkg/errors"
@@ -309,11 +308,7 @@ func (ic *interopContext) checkHashedWitness(hash util.Uint160) (bool, error) {
 // checkKeyedWitness checks hash of signature check contract with a given public
 // key against current list of script hashes for verifying in the interop context.
 func (ic *interopContext) checkKeyedWitness(key *keys.PublicKey) (bool, error) {
-	script, err := smartcontract.CreateSignatureRedeemScript(key)
-	if err != nil {
-		return false, gherr.Wrap(err, "failed to create signature script for a key")
-	}
-	return ic.checkHashedWitness(hash.Hash160(script))
+	return ic.checkHashedWitness(hash.Hash160(key.GetVerificationScript()))
 }
 
 // runtimeCheckWitness checks witnesses.

pkg/crypto/keys/publickey.go

@@ -12,6 +12,7 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/crypto"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/io"
+	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
 	"github.com/pkg/errors"
 )
 
@@ -222,13 +223,19 @@ func (p *PublicKey) EncodeBinary(w *io.BinWriter) {
 	w.WriteBytes(p.Bytes())
 }
 
+// GetVerificationScript returns NEO VM bytecode with CHECKSIG command for the
+// public key.
+func (p *PublicKey) GetVerificationScript() []byte {
+	b := p.Bytes()
+	b = append([]byte{byte(opcode.PUSHBYTES33)}, b...)
+	b = append(b, byte(opcode.CHECKSIG))
+
+	return b
+}
+
 // Signature returns a NEO-specific hash of the key.
 func (p *PublicKey) Signature() []byte {
-	b := p.Bytes()
-	b = append([]byte{0x21}, b...)
-	b = append(b, 0xAC)
-
-	sig := hash.Hash160(b)
+	sig := hash.Hash160(p.GetVerificationScript())
 
 	return sig.Bytes()
 }

pkg/crypto/keys/wif.go

@@ -90,19 +90,3 @@ func WIFDecode(wif string, version byte) (*WIF, error) {
 	w.Compressed = true
 	return w, nil
 }
-
-// GetVerificationScript returns NEO VM bytecode with checksig command for the public key.
-func (wif WIF) GetVerificationScript() []byte {
-	const (
-		pushbytes33 = 0x21
-		checksig    = 0xac
-	)
-	var (
-		vScript []byte
-		pubkey  *PublicKey
-	)
-	pubkey = wif.PrivateKey.PublicKey()
-	vScript = append([]byte{pushbytes33}, pubkey.Bytes()...)
-	vScript = append(vScript, checksig)
-	return vScript
-}

pkg/rpc/txBuilder.go

@@ -86,7 +86,7 @@ func SignTx(tx *transaction.Transaction, wif *keys.WIF) error {
 	if witness.InvocationScript, err = GetInvocationScript(tx, wif); err != nil {
 		return errs.Wrap(err, "failed to create invocation script")
 	}
-	witness.VerificationScript = wif.GetVerificationScript()
+	witness.VerificationScript = wif.PrivateKey.PublicKey().GetVerificationScript()
 	tx.Scripts = append(tx.Scripts, &witness)
 	tx.Hash()
 

pkg/smartcontract/contract.go

@@ -10,21 +10,6 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
 )
 
-// CreateSignatureRedeemScript creates a check signature script runnable by VM.
-func CreateSignatureRedeemScript(key *keys.PublicKey) ([]byte, error) {
-	buf := new(bytes.Buffer)
-	err := vm.EmitBytes(buf, key.Bytes())
-	if err != nil {
-		return nil, err
-	}
-	err = vm.EmitOpcode(buf, opcode.CHECKSIG)
-	if err != nil {
-		return nil, err
-	}
-
-	return buf.Bytes(), nil
-}
-
 // CreateMultiSigRedeemScript creates a script runnable by the VM.
 func CreateMultiSigRedeemScript(m int, publicKeys keys.PublicKeys) ([]byte, error) {
 	if m <= 1 {