f000b76879
* [FIX] Formatting and code-style - gofmt - import resort - prealloc slices - simplify code * fix vet
133 lines
2.7 KiB
Go
133 lines
2.7 KiB
Go
package crypto
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/sha256"
|
|
"fmt"
|
|
"math/big"
|
|
|
|
"github.com/pkg/errors"
|
|
)
|
|
|
|
const prefix rune = '1'
|
|
|
|
var decodeMap = map[rune]int64{
|
|
'1': 0, '2': 1, '3': 2, '4': 3, '5': 4,
|
|
'6': 5, '7': 6, '8': 7, '9': 8, 'A': 9,
|
|
'B': 10, 'C': 11, 'D': 12, 'E': 13, 'F': 14,
|
|
'G': 15, 'H': 16, 'J': 17, 'K': 18, 'L': 19,
|
|
'M': 20, 'N': 21, 'P': 22, 'Q': 23, 'R': 24,
|
|
'S': 25, 'T': 26, 'U': 27, 'V': 28, 'W': 29,
|
|
'X': 30, 'Y': 31, 'Z': 32, 'a': 33, 'b': 34,
|
|
'c': 35, 'd': 36, 'e': 37, 'f': 38, 'g': 39,
|
|
'h': 40, 'i': 41, 'j': 42, 'k': 43, 'm': 44,
|
|
'n': 45, 'o': 46, 'p': 47, 'q': 48, 'r': 49,
|
|
's': 50, 't': 51, 'u': 52, 'v': 53, 'w': 54,
|
|
'x': 55, 'y': 56, 'z': 57,
|
|
}
|
|
|
|
// Base58Decode decodes the base58 encoded string.
|
|
func Base58Decode(s string) ([]byte, error) {
|
|
var (
|
|
startIndex = 0
|
|
zero = 0
|
|
)
|
|
for i, c := range s {
|
|
if c == prefix {
|
|
zero++
|
|
} else {
|
|
startIndex = i
|
|
break
|
|
}
|
|
}
|
|
|
|
var (
|
|
n = big.NewInt(0)
|
|
div = big.NewInt(58)
|
|
)
|
|
for _, c := range s[startIndex:] {
|
|
charIndex, ok := decodeMap[c]
|
|
if !ok {
|
|
return nil, fmt.Errorf(
|
|
"invalid character '%c' when decoding this base58 string: '%s'", c, s,
|
|
)
|
|
}
|
|
n.Add(n.Mul(n, div), big.NewInt(charIndex))
|
|
}
|
|
|
|
out := n.Bytes()
|
|
buf := make([]byte, zero+len(out))
|
|
copy(buf[zero:], out[:])
|
|
|
|
return buf, nil
|
|
}
|
|
|
|
// Base58Encode encodes a byte slice to be a base58 encoded string.
|
|
func Base58Encode(bytes []byte) string {
|
|
var (
|
|
lookupTable = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
|
|
x = new(big.Int).SetBytes(bytes)
|
|
r = new(big.Int)
|
|
m = big.NewInt(58)
|
|
zero = big.NewInt(0)
|
|
encoded string
|
|
)
|
|
|
|
for x.Cmp(zero) > 0 {
|
|
x.QuoRem(x, m, r)
|
|
encoded = string(lookupTable[r.Int64()]) + encoded
|
|
}
|
|
|
|
return encoded
|
|
}
|
|
|
|
// Base58CheckDecode decodes the given string.
|
|
func Base58CheckDecode(s string) (b []byte, err error) {
|
|
b, err = Base58Decode(s)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
for i := 0; i < len(s); i++ {
|
|
if s[i] != '1' {
|
|
break
|
|
}
|
|
b = append([]byte{0x00}, b...)
|
|
}
|
|
|
|
if len(b) < 5 {
|
|
return nil, errors.New("invalid base-58 check string: missing checksum.")
|
|
}
|
|
|
|
sha := sha256.New()
|
|
sha.Write(b[:len(b)-4])
|
|
hash := sha.Sum(nil)
|
|
|
|
sha.Reset()
|
|
sha.Write(hash)
|
|
hash = sha.Sum(nil)
|
|
|
|
if bytes.Compare(hash[0:4], b[len(b)-4:]) != 0 {
|
|
return nil, errors.New("invalid base-58 check string: invalid checksum.")
|
|
}
|
|
|
|
// Strip the 4 byte long hash.
|
|
b = b[:len(b)-4]
|
|
|
|
return b, nil
|
|
}
|
|
|
|
// Base58checkEncode encodes b into a base-58 check encoded string.
|
|
func Base58CheckEncode(b []byte) string {
|
|
sha := sha256.New()
|
|
sha.Write(b)
|
|
hash := sha.Sum(nil)
|
|
|
|
sha.Reset()
|
|
sha.Write(hash)
|
|
hash = sha.Sum(nil)
|
|
|
|
b = append(b, hash[0:4]...)
|
|
|
|
return Base58Encode(b)
|
|
}
|