Creating a signed SOAP message as a string from C #
I need to make a call to a web service I have to send with a soap request like this using C #. SoapBody and TimeStamp must be signed.
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:web="http://xyzt.com/">
<soap:Header>
<wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
<wsse:BinarySecurityToken EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary" ValueType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509PKIPathv1" wsu:Id="X509-F4AF9673207AC5E0B614180667985061">MIIFsDCCBawwggSUoAMCAQICBgCaWhnEajANBgkqhkiG9w0BAQsFADBcMQswCQYDVQQGEwJUUjFNMEsGA1UEAwxETWFsaSBNw7xow7xyIEVsZWt0cm9uaWsgU2VydGlmaWthIEhpem1ldCBTYcSfbGF5xLFjxLFzxLEgLSBTw7xyw7xtIDEwHhcNMT</wsse:BinarySecurityToken>
<ds:Signature Id="SIG-3" xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
<ds:SignedInfo>
<ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
<ec:InclusiveNamespaces PrefixList="soap web" xmlns:ec="http://www.w3.org/2001/10/xml-exc-c14n#"/>
</ds:CanonicalizationMethod>
<ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
<ds:Reference URI="#id-2">
<ds:Transforms>
<ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
<ec:InclusiveNamespaces PrefixList="web" xmlns:ec="http://www.w3.org/2001/10/xml-exc-c14n#"/>
</ds:Transform>
</ds:Transforms>
<ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
<ds:DigestValue>IZVrIpPCxiPcvyVOVv/d4nRPZWM=</ds:DigestValue>
</ds:Reference>
<ds:Reference URI="#TS-1">
<ds:Transforms>
<ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
<ec:InclusiveNamespaces PrefixList="wsse soap web" xmlns:ec="http://www.w3.org/2001/10/xml-exc-c14n#"/>
</ds:Transform>
</ds:Transforms>
<ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
<ds:DigestValue>fltghgDztDtuVQX7y4t0ZJxAnxE=</ds:DigestValue>
</ds:Reference>
</ds:SignedInfo>
<ds:SignatureValue>IOVXxBTp053aNJMbQj+VTiBblZ63peyJ1vWazKmEWNxN7RaeFfKELoxede8xQEqzSaB/u8exC7LLGYiEdChboVCf9liLMN4MmNj5JR6gfDrsL3azThf5hxLQ+WIE20PRoU6ozpp20zC1IaO3IU4ZaRLw</ds:SignatureValue>
<ds:KeyInfo Id="KI-F4AF9673207AC5E0B614180667986422">
<wsse:SecurityTokenReference wsse11:TokenType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509PKIPathv1" wsu:Id="STR-F4AF9673207AC5E0B614180667986643" xmlns:wsse11="http://docs.oasis-open.org/wss/oasis-wss-wssecurity-secext-1.1.xsd">
<wsse:Reference URI="#X509-F4AF9673207AC5E0B614180667985061" ValueType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509PKIPathv1"/>
</wsse:SecurityTokenReference>
</ds:KeyInfo>
</ds:Signature>
<wsu:Timestamp wsu:Id="TS-1">
<wsu:Created>2014-12-08T21:26:36.191Z</wsu:Created>
<wsu:Expires>2014-12-08T21:36:36.191Z</wsu:Expires>
</wsu:Timestamp>
</wsse:Security>
</soap:Header>
<soap:Body wsu:Id="id-2" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
<web:getStatus>
<itemID>1234567</itemID>
</web:getStatus>
</soap:Body>
</soap:Envelope>
I created this soap request and got a good response using WCF Client CustomBinding and a .pfx file with a private key certificate.
Most of the soap message signing examples use a certificate from a certificate store or a pfx file. But in my scenario, the user certificate (with the private key) stored on the smart card cannot export the private key of the certificate. So in this case, I cannot use the WCF CustomBinding, or I cannot use the SignedXml class to sign the SOAP message, because when I try to get the certificate programmatically, the private key is missing. (Also I got the private key using the NCryptoki-PKCS wrapper, but this type of private key is different from RSA, which I can't set for the WCF client or SignedXmlClass private key.)
So I am trying to create this SOAP message as a string and manually create DigestValues, BinarySecurityToken, and SignatureValue using a smart card.
I can calculate the BinarySecurityToken value as:
var certificate = GetX5092Certificate(); // X5092 certificate on smart card without private key
string binarySecToken= Convert.ToBase64String(certificate.RawData);
Also I have some code to calculate the digest value as:
byte[] dataToHashTS = Encoding.UTF8.GetBytes(TimeStampReference.OuterXml);
XmlDsigExcC14NTransform transformDataTS = new XmlDsigExcC14NTransform("wsse soap web");
transformDataTS.LoadInput(new MemoryStream(dataToHashTS));
byte[] bDigestDataTS = transformDataTS.GetDigestedOutput(SHA1Managed.Create());
string sDigestDataTS = Convert.ToBase64String(bDigestDataTS); //timestamp digest
-
I'm not sure if I calculated the digest values correctly or not?
-
In order to compute the SignatureValue I think I need to get the hash of the SignedInfo part. I have a method that signs content (byte array) with a smart card. So how can I send SignedInfo content to this method? I mean, is it enough to get the hash of the SignedInfo block as a string? OR I got SignedInfo as XmlElement, then converted + hash as I did to calculate digest values?
Any help would be much appreciated. Thank.
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- For DigestValue, you need to canonicalize the string like this:
<u:Timestamp u:Id="_0" xmlns:u="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
<u:Created>2016-06-14T22:56:10.896Z</u:Created>
<u:Expires>2016-06-14T23:01:10.896Z</u:Expires>
</u:Timestamp>
So, you can just put this line as a parameter here:
private string CanonicalizeDsig(string input)
{
XmlDocument doc = new XmlDocument();
doc.PreserveWhitespace = false;
try
{
doc.LoadXml(input);
XmlDsigC14NTransform trans = new XmlDsigC14NTransform();
trans.LoadInput(doc);
String c14NInput = new StreamReader((Stream)trans.GetOutput(typeof(Stream))).ReadToEnd();
return c14NInput;
}
catch (Exception ex)
{
return String.Empty;
}
}
After canonicalization, you can now compute the hash: (my SHA1 example). So let's put the return value of the above method on the parameter of this one. get something like JCMdwz5g8iq05Lj6tjfDOxKqT4k =
private string ComputeHashSHA1(string input)
{
try
{
SHA1CryptoServiceProvider sha1Hasher = new SHA1CryptoServiceProvider();
byte[] hashedDataBytes = sha1Hasher.ComputeHash(Encoding.UTF8.GetBytes(input));
string digestValue = Convert.ToBase64String(hashedDataBytes);
return digestValue;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return String.Empty;
}
}
- The meaning of the signature is complex and I can only cover a specific example. Check your WSDL service if it has a policy that looks something like this.
<sp:Trust10> <wsp:Policy> <sp:MustSupportIssuedTokens/> <sp:RequireClientEntropy/> <sp:RequireServerEntropy/> </wsp:Policy>
This means that you need to combine the client entropy (which is your key - any string based on which 64 is sent to the server to request a token) and Server Entropy (base 64 return key)
You can concatenate them using the Microsoft.IdentityModel dll where there is a KeyGenerator object.
Your input will be something like this and it also needs canonicalization with DsigExcC14N:
<SignedInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
<SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#hmac-sha1"/>
<Reference URI="#_0">
<Transforms>
<Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
</Transforms>
<DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
<DigestValue>JCMdwz5g8iq05Lj6tjfDOxKqT4k=</DigestValue>
</Reference>
</SignedInfo>
Here is the canonization:
private string CanonicalizeExc(string input)
{
XmlDocument doc = new XmlDocument();
doc.PreserveWhitespace = false;
try
{
doc.LoadXml(input);
XmlDsigExcC14NTransform trans = new XmlDsigExcC14NTransform();
trans.LoadInput(doc);
String c14NInput = new StreamReader((Stream)trans.GetOutput(typeof(Stream))).ReadToEnd();
return c14NInput;
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
return String.Empty;
}
}
Then this is how you get the signature value:
private string ComputeHMACSHA1_PSHA(string input, string serversecret, string clientsecret)
{
try
{
byte[] signedInfoBytes = Encoding.UTF8.GetBytes(input);
byte[] binarySecretBytesServer = Convert.FromBase64String(serversecret);
byte[] binarySecretBytesClient = Convert.FromBase64String(clientsecret);
byte[] key = KeyGenerator.ComputeCombinedKey(binarySecretBytesClient, binarySecretBytesServer, 256);
HMACSHA1 hmac = new HMACSHA1(key);
hmac.Initialize();
byte[] hmacHash = hmac.ComputeHash(signedInfoBytes);
string signatureValue = Convert.ToBase64String(hmacHash);
return signatureValue;
}
catch (Exception ex)
{
return string.Empty;
}
}
This will give you something like this. kykmlowWIW4TXRcCi46OfZPUBKQ =
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