pemkey save in clear text is insecure

[ghost]

in trueconsensus/fastchain/genkeys.go WriteNewKeys function. (which called in pbftserverengine.go -> main() -> cfg.GenerateKeysToFile() -> WriteNewKeys(cfg.Network.NumKeys, cfg.Logistics.KD))

func WriteNewKeys(kcount int, kdir string) {
    for k := 0; k < kcount; k++ {
        privateKey, _ := ecdsa.GenerateKey(ethcrypto.S256(), rand.Reader)
        publicKey := &privateKey.PublicKey

        pemEncoded := hex.EncodeToString(ethcrypto.FromECDSA(privateKey))
        pemEncodedPub := hex.EncodeToString(ethcrypto.FromECDSAPub(publicKey))

        pemkeyFname := fmt.Sprintf("sign%v.pem", k)
        err1 := ioutil.WriteFile(path.Join(kdir, pemkeyFname), []byte(pemEncoded), 0600)
        common.CheckErr(err1)
        pubkeyFname := fmt.Sprintf("sign%v.pub", k)
        err2 := ioutil.WriteFile(path.Join(kdir, pubkeyFname), []byte(pemEncodedPub), 0644)
        common.CheckErr(err2)
    }
}

ethcrypto.FromECDSA just make privatekey to byte type. function save the pemkey as pemEncoded which Unencrypted.

If some node be attacked, the attacker can steal pemkey of users with a malicious software.