/// <summary>
/// Returns hash characters based on digits passed to it.
/// </summary>
/// <param name="digits">Digits to checksum.</param>
/// <param name="returnAllDigits">If true, all digits are to be returned instead of only hash.</param>
/// <exception cref="System.ArgumentNullException">Digits cannot be null.</exception>
public static string ComputeHash(string digits, bool returnAllDigits)
{
if (digits == null)
{
throw new ArgumentNullException(nameof(digits), "Digits cannot be null.");
}
digits = digits.Replace(" ", "").Replace("-", ""); //ignore dashes and spaces
using (var checksum = new Damm()) {
checksum.ComputeHash(Encoding.ASCII.GetBytes(digits));
if (returnAllDigits)
{
return(digits + checksum.HashAsChar.ToString());
}
else
{
return(checksum.HashAsChar.ToString());
}
}
}
/// <summary>
/// Returns if hash matches digits.
/// </summary>
/// <param name="digitsWithHash">Digits with appended hash.</param>
/// <exception cref="System.ArgumentNullException">Digits cannot be null.</exception>
public static bool ValidateHash(string digitsWithHash)
{
if (digitsWithHash == null)
{
throw new ArgumentNullException(nameof(digitsWithHash), "Digits cannot be null.");
}
digitsWithHash = digitsWithHash.Replace(" ", "").Replace("-", ""); //ignore dashes and spaces
if (digitsWithHash.Length < 1)
{
throw new ArgumentOutOfRangeException(nameof(digitsWithHash), "Digits cannot be less than one character long.");
}
var digits = digitsWithHash.Substring(0, digitsWithHash.Length - 1);
var hash = digitsWithHash[digitsWithHash.Length - 1];
using (var checksum = new Damm()) {
checksum.ComputeHash(Encoding.ASCII.GetBytes(digits));
return(hash == checksum.HashAsChar);
}
}
/// <summary>
/// Returns hash characters based on digits passed to it.
/// </summary>
/// <param name="digits">Digits to checksum.</param>
/// <exception cref="System.ArgumentNullException">Digits cannot be null.</exception>
public static string ComputeHash(string digits)
{
return(Damm.ComputeHash(digits, returnAllDigits: false));
}