blockchain_go/base58.go

53 lines
1.0 KiB
Go

package main
import (
"bytes"
"math/big"
)
var b58Alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
// Base58Encode encodes a byte array to Base58
func Base58Encode(input []byte) []byte {
var result []byte
x := big.NewInt(0).SetBytes(input)
base := big.NewInt(int64(len(b58Alphabet)))
zero := big.NewInt(0)
mod := &big.Int{}
for x.Cmp(zero) != 0 {
x.DivMod(x, base, mod)
result = append(result, b58Alphabet[mod.Int64()])
}
// https://en.bitcoin.it/wiki/Base58Check_encoding#Version_bytes
if input[0] == 0x00 {
result = append(result, b58Alphabet[0])
}
ReverseBytes(result)
return result
}
// Base58Decode decodes Base58-encoded data
func Base58Decode(input []byte) []byte {
result := big.NewInt(0)
for _, b := range input {
charIndex := bytes.IndexByte(b58Alphabet, b)
result.Mul(result, big.NewInt(58))
result.Add(result, big.NewInt(int64(charIndex)))
}
decoded := result.Bytes()
if input[0] == b58Alphabet[0] {
decoded = append([]byte{0x00}, decoded...)
}
return decoded
}