Código Único de Factura en C Sharp

using System;
using System.Numerics;

public class CodigoUnico {
 public static void Main() {
  String cuf = obtenerCUF("123456789", "20190113163721242", 0, 2, 1, 1, 10, 10, 0);
  Console.WriteLine("CUF: " + cuf);
 }

 /**
  * @param nit NIT emisor
  * @param fh Fecha y Hora en formato yyyyMMddHHmmssSSS
  * @param sucursal
  * @param mod Modalidad
  * @param temision Tipo de Emision
  * @param cdf Codigo Documento Fiscal
  * @param tds Tipo Documento Sector
  * @param nf Numero de Factura
  * @param pos Punto de Venta
  * @return CUF Codigo Unico de Factura
  */
 public static String obtenerCUF(String nit, String fh, int sucursal, int mod, int temision, int cdf, int tds, int nf, int pos) {
  String cadena = "";

  /**
   * PASO 1 y PASO2 Completa con ceros cada campo y concatena todo en una
   * sola cadena
   */
  cadena += BigInteger.Parse(nit).ToString("D13");
  cadena += fh;
  cadena += sucursal.ToString("D4");
  cadena += mod;
  cadena += temision;
  cadena += cdf;
  cadena += tds.ToString("D2");
  cadena += nf.ToString("D8");
  cadena += pos.ToString("D4");

  /**
   * Paso 3 Obtiene modulo 11 y adjunta resultado a la cadena
   */
  String mod11 = calculaDigitoMod11(cadena, 1, 9, false);
  cadena += mod11;

  /**
   * paso 4 Aplica base16
   */
  BigInteger cuf = BigInteger.Parse(cadena);
  return cuf.ToString("X");
 }

 /**
  * @see https://impuestos.gob.bo/ ALGORITMO BASE 11 ? MÓDULO 11
  * Original en lenguaje java
  */
 public static String calculaDigitoMod11(String dado, int numDig, int limMult, bool x10) {
  int mult, soma, i, n, dig;
  if (!x10) {
   numDig = 1;
  }
  for (n = 1; n <= numDig; n++) {
   soma = 0;
   mult = 2;
   for (i = dado.Length - 1; i >= 1; i--) {
    soma += (mult * Int32.Parse(dado.Substring(i, 1)));

    if (++mult > limMult) {
     mult = 2;
    }
   }
   if (x10) {
    dig = ((soma * 10) % 11) % 10;
   } else {
    dig = soma % 11;
   }
   if (dig == 10) {
    dado
     += "1";
   }
   if (dig == 11) {
    dado
     += "0";
   }
   if (dig < 10) {
    dado += dig;
   }
  }
  return dado.Substring(dado.Length - numDig, 1);
 }

}

CUF> 1.- 159FFE6FB1986A24BB32DBE5A2A34214B245A6A3 = 159FFE6FB1986A24BB32DBE5A2A34214B245A6A3 -> True
CUF> 2.- 159FFE6FB1986A24BB32EAB8592FA23EE2CA4D48 = 159FFE6FB1986A24BB32EAB8592FA23EE2CA4D48 -> True
CUF> 3.- 159FFE6FB1986A24BB32EAB857CFF35D787AF3E4 = 159FFE6FB1986A24BB32EAB857CFF35D787AF3E4 -> True
CUF> 4.- 159FFE6FB1986A24BB32ECD6730CF0AB8D2C1A89 = 159FFE6FB1986A24BB32ECD6730CF0AB8D2C1A89 -> True
CUF> 5.- 159FFE6FB1986A24BB32ECD671AD41CA22DCC125 = 159FFE6FB1986A24BB32ECD671AD41CA22DCC125 -> True
CUF> 6.- 159FFE6FB1986A24BB32ECD673141DD973A167C5 = 159FFE6FB1986A24BB32ECD673141DD973A167C5 -> True
CUF> 7.- 159FFE6FB1986A24BB32EEF48B8A9036CD3E8E61 = 159FFE6FB1986A24BB32EEF48B8A9036CD3E8E61 -> True
CUF> 8.- 159FFE6FB1986A24BB32F112A6D23600D0433506 = 159FFE6FB1986A24BB32F112A6D23600D0433506 -> True
CUF> 9.- 159FFE6FB1986A24BB32F112A572871F65F3DBA2 = 159FFE6FB1986A24BB32F112A572871F65F3DBA2 -> True
CUF> 10.- 159FFE6FB1986A24BB32F330C0AF846D7AA50240 = 159FFE6FB1986A24BB32F330C0AF846D7AA50240 -> True
CUF> 11.- 159FFE6FB1986A24BB32F330BF4FD58C1055A8E7 = 159FFE6FB1986A24BB32F330BF4FD58C1055A8E7 -> True
CUF> 12.- 159FFE6FB1986A24BB32F330C0B6B19B611A4F87 = 159FFE6FB1986A24BB32F330C0B6B19B611A4F87 -> True
CUF> 13.- 159FFE6FB1986A24BB32F54ED92D23F8BAB77628 = 159FFE6FB1986A24BB32F54ED92D23F8BAB77628 -> True
CUF> 14.- 159FFE6FB1986A24BB32F54EDA9400080B7C1CC8 = 159FFE6FB1986A24BB32F54EDA9400080B7C1CC8 -> True
CUF> 15.- 159FFE6FB1986A24BB32F54ED9345126A12CC364 = 159FFE6FB1986A24BB32F54ED9345126A12CC364 -> True
CUF> 16.- 159FFE6FB1986A24BB32F76CF4714E74B5DDEA09 = 159FFE6FB1986A24BB32F76CF4714E74B5DDEA09 -> True
CUF> 17.- 159FFE6FB1986A24BB32F76CF3119F934B8E90A5 = 159FFE6FB1986A24BB32F76CF3119F934B8E90A5 -> True
CUF> 18.- 159FFE6FB1986A24BB32F98B0E59455D4E933741 = 159FFE6FB1986A24BB32F98B0E59455D4E933741 -> True
CUF> 19.- 159FFE6FB1986A24BB32F98B0CEEEDFFF5F05DE6 = 159FFE6FB1986A24BB32F98B0CEEEDFFF5F05DE6 -> True
CUF> 20.- 159FFE6FB1986A24BB32FBA9283693C9F8F50486 = 159FFE6FB1986A24BB32FBA9283693C9F8F50486 -> True
CUF> 21.- 159FFE6FB1986A24BB32FBA926D6E4E88EA5AB22 = 159FFE6FB1986A24BB32FBA926D6E4E88EA5AB22 -> True
CUF> 22.- 159FFE6FB1986A24BB32FDC74213E236A356D1C7 = 159FFE6FB1986A24BB32FDC74213E236A356D1C7 -> True
CUF> 23.- 159FFE6FB1986A24BB32FDC740B4335539077863 = 159FFE6FB1986A24BB32FDC740B4335539077863 -> True
CUF> 24.- 159FFE6FB1986A24BB32FDC7421A3E357D7FBF04 = 159FFE6FB1986A24BB32FDC7421A3E357D7FBF04 -> True
CUF> 25.- 159FFE6FB1986A24BB32FFE55A90B092D71CE5A5 = 159FFE6FB1986A24BB32FFE55A90B092D71CE5A5 -> True
CUF> 26.- 159FFE6FB1986A24BB32FFE55C1B139497A28C43 = 159FFE6FB1986A24BB32FFE55C1B139497A28C43 -> True
CUF> 27.- 159FFE6FB1986A24BB32FFE55ABB64B32D5332E1 = 159FFE6FB1986A24BB32FFE55ABB64B32D5332E1 -> True
CUF> 28.- 159FFE6FB1986A24BB33020375F8620142045984 = 159FFE6FB1986A24BB33020375F8620142045984 -> True
CUF> 29.- 159FFE6FB1986A24BB3302037498B31FD7B50020 = 159FFE6FB1986A24BB3302037498B31FD7B50020 -> True
CUF> 30.- 159FFE6FB1986A24BB33020375FF8F2F2879A6C2 = 159FFE6FB1986A24BB33020375FF8F2F2879A6C2 -> True
CUF> 31.- 159FFE6FB1986A24BB3304218E76018C8216CD67 = 159FFE6FB1986A24BB3304218E76018C8216CD67 -> True
CUF> 32.- 159FFE6FB1986A24BB3304218FDCDD9BD2DB7407 = 159FFE6FB1986A24BB3304218FDCDD9BD2DB7407 -> True
CUF> 33.- 159FFE6FB1986A24BB33063FA85DF8751ACC1AA1 = 159FFE6FB1986A24BB33063FA85DF8751ACC1AA1 -> True
CUF> 34.- 159FFE6FB1986A24BB33063FA9BA2C087D3D4141 = 159FFE6FB1986A24BB33063FA9BA2C087D3D4141 -> True
CUF> 35.- 159FFE6FB1986A24BB33063FA85A7D2712EDE7E6 = 159FFE6FB1986A24BB33063FA85A7D2712EDE7E6 -> True
CUF> 36.- 159FFE6FB1986A24BB33085DC3A222F115F28E82 = 159FFE6FB1986A24BB33085DC3A222F115F28E82 -> True
CUF> 37.- 159FFE6FB1986A24BB33085DC237CB93BD4FB527 = 159FFE6FB1986A24BB33085DC237CB93BD4FB527 -> True
CUF> 38.- 159FFE6FB1986A24BB330A7BDD7F715DC0545BC3 = 159FFE6FB1986A24BB330A7BDD7F715DC0545BC3 -> True
CUF> 39.- 159FFE6FB1986A24BB330A7BDC1FC27C56050261 = 159FFE6FB1986A24BB330A7BDC1FC27C56050261 -> True
CUF> 40.- 159FFE6FB1986A24BB330A7BDD7BF60FB8762901 = 159FFE6FB1986A24BB330A7BDD7BF60FB8762901 -> True
CUF> 41.- 159FFE6FB1986A24BB330C99F5FD10E90066CFA2 = 159FFE6FB1986A24BB330C99F5FD10E90066CFA2 -> True
CUF> 42.- 159FFE6FB1986A24BB330C99F763ECF8512B7642 = 159FFE6FB1986A24BB330C99F763ECF8512B7642 -> True
CUF> 43.- 159FFE6FB1986A24BB330C99F5F9959AF8889CE9 = 159FFE6FB1986A24BB330C99F5F9959AF8889CE9 -> True
CUF> 44.- 159FFE6FB1986A24BB330EB811413B64FB8D4385 = 159FFE6FB1986A24BB330EB811413B64FB8D4385 -> True
CUF> 45.- 159FFE6FB1986A24BB330EB80FE18C83913DEA21 = 159FFE6FB1986A24BB330EB80FE18C83913DEA21 -> True
CUF> 46.- 159FFE6FB1986A24BB3310D62B1E89D1A5EF10C6 = 159FFE6FB1986A24BB3310D62B1E89D1A5EF10C6 -> True
CUF> 47.- 159FFE6FB1986A24BB3310D629BE09C12F535763 = 159FFE6FB1986A24BB3310D629BE09C12F535763 -> True
CUF> 48.- 159FFE6FB1986A24BB3312F44505AF8B3257FE01 = 159FFE6FB1986A24BB3312F44505AF8B3257FE01 -> True
CUF> 49.- 159FFE6FB1986A24BB3312F4439B582DD9B524A4 = 159FFE6FB1986A24BB3312F4439B582DD9B524A4 -> True
CUF> 50.- 159FFE6FB1986A24BB3315125EE2FDF7DCB9CB42 = 159FFE6FB1986A24BB3315125EE2FDF7DCB9CB42 -> True