Official Go implementation of the Ethereum protocol
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go-ethereum/ethcrypto/mnemonic.go

87 lines
2.0 KiB

package ethcrypto
import (
"fmt"
"io/ioutil"
"os"
"path"
"path/filepath"
"runtime"
"strconv"
"strings"
)
func InitWords() []string {
_, thisfile, _, _ := runtime.Caller(1)
filename := path.Join(path.Dir(thisfile), "mnemonic.words.lst")
if _, err := os.Stat(filename); os.IsNotExist(err) {
fmt.Printf("reading mnemonic word list file 'mnemonic.words.lst' from source folder failed, looking in current folder.")
dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
if err != nil {
panic(fmt.Errorf("problem getting current folder: ", err))
}
filename = path.Join(dir, "mnemonic.words.lst")
}
content, err := ioutil.ReadFile(filename)
if err != nil {
panic(fmt.Errorf("reading mnemonic word list file 'mnemonic.words.lst' failed: ", err))
}
return strings.Split(string(content), "\n")
}
var words = InitWords()
// 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(words))
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, words[w1], words[w2], words[w3])
}
return out
}
func MnemonicDecode(wordsar []string) string {
var out string
n := int64(len(words))
for i := 0; i < len(wordsar); i += 3 {
word1 := wordsar[i]
word2 := wordsar[i+1]
word3 := wordsar[i+2]
w1 := IndexOf(words, word1)
w2 := IndexOf(words, word2)
w3 := IndexOf(words, 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
}