Use simple key generation source for faster account creation (#296)

load/app/account.go

@@ -19,6 +19,7 @@ package app
 import (
 	"context"
 	"crypto/ecdsa"
+	"encoding/binary"
 	"fmt"
 	"math/big"
 	"sync/atomic"
@@ -35,29 +36,25 @@ import (
 // Any factory using the same mnemonic, feederId and appId produce the same sequence of accounts,
 // which can be used to reuse existing accounts from previous runs.
 type AccountFactory struct {
-	keyGenerator *KeyGenerator
-	chainID      *big.Int
-	numAccounts  int64
+	chainID     *big.Int
+	numAccounts int64
 }
 
 // NewAccountFactory creates a new AccountFactory, generating accounts for given feeder and app.
 // Re-creating a factory using the same feederId and appId will produce the same sequence of accounts.
 func NewAccountFactory(chainID *big.Int, feederId, appId uint32) (*AccountFactory, error) {
-	keyGenerator, err := NewKeyGenerator(Mnemonic, feederId, appId)
-	if err != nil {
-		return nil, err
-	}
 	return &AccountFactory{
-		keyGenerator: keyGenerator,
-		chainID:      chainID,
-		numAccounts:  0,
+		chainID:     chainID,
+		numAccounts: 0,
 	}, nil
 }
 
 // CreateAccount generates the next account in the sequence generated by the AccountFactory.
 func (f *AccountFactory) CreateAccount(rpcClient rpc.RpcClient) (*Account, error) {
 	id := atomic.AddInt64(&f.numAccounts, 1)
-	privateKey, err := f.keyGenerator.GeneratePrivateKey(uint32(id))
+	d := make([]byte, 32)
+	binary.BigEndian.PutUint64(d[:24], uint64(id))
+	privateKey, err := crypto.ToECDSA(d)
 	if err != nil {
 		return nil, err
 	}
@@ -131,10 +128,6 @@ func (a *Account) getNextNonce() uint64 {
 	return current - 1
 }
 
-func (a *Account) getCurrentNonce() uint64 {
-	return atomic.LoadUint64(&a.nonce)
-}
-
 // CreateValidator creates non genesis validator trough createValidator sfc call
 func (a *Account) CreateValidator(SFCContract *contract.SFC, rpcClient rpc.RpcClient) (*types.Transaction, error) {
 	// get price of gas from the network