public static string ToCheckSumAddress(string address)
{
if (!address.StartsWith("0x"))
{
throw new Exception("not a valid base 16 address");
}
address = address.ToLower().Replace("0x", "");
string hash = ByteUtil.ByteArrayToHexString(HashUtil.CalculateSha256Hash(ByteUtil.HexStringToByteArray(address)));
StringBuilder ret = new StringBuilder("0x");
byte[] x = ByteUtil.HexStringToByteArray(hash);
BigInteger v = new BigInteger(ByteUtil.HexStringToByteArray(hash));
for (int i = 0; i < address.Length; i++)
{
if ("1234567890".IndexOf(address.ToCharArray()[i]) != -1)
{
ret.Append(address.ToCharArray()[i]);
}
else
{
BigInteger checker = v.And(BigInteger.ValueOf(2).Pow(255 - 6 * i));
ret.Append(checker.CompareTo(BigInteger.ValueOf(1)) < 0 ? address.ToCharArray()[i].ToString().ToLower() : address.ToCharArray()[i].ToString().ToUpper());
}
}
return(ret.ToString());
}