plugeth/crypto/mnemonic.go
2015-07-07 14:12:44 +02:00

77 lines
2.0 KiB
Go

// Copyright 2014 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package crypto
import (
"fmt"
"strconv"
)
// TODO: See if we can refactor this into a shared util lib if we need it multiple times
func IndexOf(slice []string, value string) int64 {
for p, v := range slice {
if v == value {
return int64(p)
}
}
return -1
}
func MnemonicEncode(message string) []string {
var out []string
n := int64(len(MnemonicWords))
for i := 0; i < len(message); i += (len(message) / 8) {
x := message[i : i+8]
bit, _ := strconv.ParseInt(x, 16, 64)
w1 := (bit % n)
w2 := ((bit / n) + w1) % n
w3 := ((bit / n / n) + w2) % n
out = append(out, MnemonicWords[w1], MnemonicWords[w2], MnemonicWords[w3])
}
return out
}
func MnemonicDecode(wordsar []string) string {
var out string
n := int64(len(MnemonicWords))
for i := 0; i < len(wordsar); i += 3 {
word1 := wordsar[i]
word2 := wordsar[i+1]
word3 := wordsar[i+2]
w1 := IndexOf(MnemonicWords, word1)
w2 := IndexOf(MnemonicWords, word2)
w3 := IndexOf(MnemonicWords, word3)
y := (w2 - w1) % n
z := (w3 - w2) % n
// Golang handles modulo with negative numbers different then most languages
// The modulo can be negative, we don't want that.
if z < 0 {
z += n
}
if y < 0 {
y += n
}
x := w1 + n*(y) + n*n*(z)
out += fmt.Sprintf("%08x", x)
}
return out
}