1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Xml;
using System.IO;

namespace ConsoleApplication31
{
class Program
{
static void Main(string[] args)
{
GetCanonization();
//GetSignature();

}

static void GetSignature()
{ 
XmlDocument doc = new XmlDocument();
//doc.LoadXml("<root><x xmlns=\"ns\" Id=\"_0\"></x><y attr=\"value\" Id=\"_1\"></y><z><w Id=\"_2\"></w></z></root>");
doc.LoadXml("<Envelope xmlns=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:ws=\"http://www.w3.org/2005/08/addressing\"><ws:ReplyTo xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" wsu:Id=\"_5\"><ws:Address xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" wsu:Id=\"_6\">http://www.w3.org/2005/08/addressing/role/anonymous</ws:Address></ws:ReplyTo></Envelope>");
SignedXml signedXml = new SignedXml(doc);

var c = new X509Certificate2(
File.ReadAllBytes(@"C:\Program Files\Microsoft WSE\v2.0\Samples\Sample Test Certificates\Client Private.pfx"), "wse2qs");

signedXml.SigningKey = c.PrivateKey;
signedXml.Signature.SignedInfo.CanonicalizationMethod = "http://www.w3.org/2001/10/xml-exc-c14n#";

Reference ref0 = new Reference();
ref0.Uri = "#_0";
Reference ref1 = new Reference();
ref1.Uri = "#_1";
Reference ref2 = new Reference();
ref2.Uri = "#_2";

var t = new XmlDsigExcC14NTransform();
ref0.AddTransform(t);
ref1.AddTransform(t);
ref2.AddTransform(t);

signedXml.AddReference(ref0);
signedXml.AddReference(ref1);
signedXml.AddReference(ref2);

signedXml.ComputeSignature();
var xmlDigitalSignature = signedXml.GetXml();
var s = xmlDigitalSignature.OuterXml;
}

static void GetCanonization()
{
var c = new XmlDsigExcC14NTransform(true, "");
var doc = new XmlDocument();
doc.PreserveWhitespace = true;
doc.LoadXml("<Envelope xmlns=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:ws=\"http://www.w3.org/2005/08/addressing\"><ws:ReplyTo xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" wsu:Id=\"_5\"><ws:Address xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" wsu:Id=\"_6\">http://www.w3.org/2005/08/addressing/role/anonymous</ws:Address></ws:ReplyTo></Envelope>");
var node = doc.SelectSingleNode("//*[local-name(.)='ReplyTo']");
var nodes = node.SelectNodes(".|.//*|.//text()|.//@*");
c.LoadInput(nodes);

var h = new SHA1CryptoServiceProvider();
var b = c.GetDigestedOutput(h);
var b64 = Convert.ToBase64String(b);

var res = c.GetOutput() as MemoryStream;
string s2 = System.Text.Encoding.UTF8.GetString(res.ToArray()); 
}
}
}