public string SHA1_Hash(string str_sha1_in)
{
SHA1 sha1 = new SHA1CryptoServiceProvider();
byte[] bytes_sha1_in = UTF8Encoding.Default.GetBytes(str_sha1_in);
byte[] bytes_sha1_out = sha1.ComputeHash(bytes_sha1_in);
string str_sha1_out = BitConverter.ToString(bytes_sha1_out);
str_sha1_out = str_sha1_out.Replace("-", "").ToLower();
return str_sha1_out;
}