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Unicode C++

Decrypt a SAML Response

See more Encryption Examples

Demonstrates how to decrypt a SAML response.

Chilkat Unicode C++ Downloads

Unicode C++
#include <CkHttpW.h>
#include <CkStringBuilderW.h>
#include <CkXmlW.h>
#include <CkPrivateKeyW.h>
#include <CkRsaW.h>
#include <CkBinDataW.h>
#include <CkCrypt2W.h>

void ChilkatSample(void)
    {
    bool success = false;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // This example decrypts this SAML response:

    // <?xml version="1.0" encoding="UTF-8" ?>
    // <saml2p:Response Destination="https://deskflow-asp2.com/ubc/ubcdfe.dll/cwlacs" ID="_e4585eaeedbcaf7c24dff7f1ee2499f5" IssueInstant="2018-10-11T17:46:20.727Z" Version="2.0" xmlns:saml2p="urn:oasis:names:tc:SAML:2.0:protocol">
    //     <saml2:Issuer xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">https://authentication.stg.id.ubc.ca</saml2:Issuer>
    //     <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
    //         <ds:SignedInfo>
    //             <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
    //             <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
    //             <ds:Reference URI="#_e4585eaeedbcaf7c24dff7f1ee2499f5">
    //                 <ds:Transforms>
    //                     <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
    //                     <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
    //                 </ds:Transforms>
    //                 <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
    //                 <ds:DigestValue>1ui22tqFyYEOoWI19CMwz4n+ynxNjLDGdTeRMdi60EU=</ds:DigestValue>
    //             </ds:Reference>
    //         </ds:SignedInfo>
    //         <ds:SignatureValue>ROg7FXV6vsp8socVhdo76/i7cRHGGKIveAiScKdujZT0QrHVqIvvbZ/RnwvEMJ9H9i/kJFAQA171
    // 		Eo2kDjSdvNFQ/YcKaJUwMtAwT05yVatGV42RZKEf7ME+vpcCTR1LWZdrhat1FWCg1MNQwNWB0EL5
    // 		fEP2a4jAcSTB8tFbjTAHsv7IWC39E5RVv99mACYXLa7iGZLtORANZxgYu5qQgmH6pUkI6Z1cpmf+
    // 		m9mIjKM6LF0EvLfWOBWL6udZ+GsHPOLjVTJg+1S0xb9FQCYDVW1QhbjSS0icKHKTNNbrsaxllVDY
    // 		m4q27YQjRh+XxugPgvsZ61Pxlto8Jbg+6jUlMQ==</ds:SignatureValue>
    //         <ds:KeyInfo>
    //             <ds:X509Data>
    //                 <ds:X509Certificate>MIIDTTCCAjWgAwIBAgIVAJccYyIV6wly8XyddumpgnHMJ2JLMA0GCSqGSIb3DQEBCwUAMCcxJTAj
    // 			BgNVBAMMHGF1dGhlbnRpY2F0aW9uLnN0Zy5pZC51YmMuY2EwHhcNMTcwMzAxMTk1NDM0WhcNMzcw
    // 			...
    // 			xUuh6HuHKIwQqHBz7udxbH3Zbb6jXGDJjiDHt1LRJ8xbVisFIcDlIwsGQQi0HeEJfx4P</ds:X509Certificate>
    //             </ds:X509Data>
    //         </ds:KeyInfo>
    //     </ds:Signature>
    //     <saml2p:Status>
    //         <saml2p:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/>
    //     </saml2p:Status>
    //     <saml2:EncryptedAssertion xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">
    //         <xenc:EncryptedData Id="_314d80b9cf02d8eda8d686a6ffd626cf" Type="http://www.w3.org/2001/04/xmlenc#Element" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
    //             <xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes128-cbc" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"/>
    //             <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
    //                 <xenc:EncryptedKey Id="_d7b6da6fb59a627ebb4a96928441ab79" Recipient="https://ubcdfe.deskflow-asp2.com" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
    //                     <xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
    //                         <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"/>
    //                     </xenc:EncryptionMethod>
    //                     <ds:KeyInfo>
    //                         <ds:X509Data>
    //                             <ds:X509Certificate>MIICuzCCAiQCCQD3bpigRnKMSzANBgkqhkiG9w0BAQsFADCBoTELMAkGA1UEBhMCQ0ExEDAOBgNV
    // 				BAgMB09udGFyaW8xEDAOBgNVBAcMB1Rvcm9udG8xJjAkBgNVBAoMHVRhY3RpY2FsIEJ1c2luZXNz
    // 				...
    // 				kVRcHd1UK3q7G8FoykWjdQz/0EoMTfEZ+Md56mLOe48eMUZV2ONZuL1kDCEKw1UwkaDQI4Pf8pzx
    // 				82b9rgw9wBDtvu5eFPlUGEGIBw==</ds:X509Certificate>
    //                         </ds:X509Data>
    //                     </ds:KeyInfo>
    //                     <xenc:CipherData xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
    //                         <xenc:CipherValue>BNHfUOpgdPE5BgpN2VIZIDthMAv1rxk91qVnWyCZOG9bmUKChJtTUqMpndot7VJwYuyKFshkAdnT
    // 				D79KGdlSA1xHKcVeZXXzDWglqSyYjzhDCsyOhPaI4HelMFgCLwyFz89uEpUpqlvfl8ol3Am/XnzQ
    // 				Vp7V7oS76hocjUI51Qs=</xenc:CipherValue>
    //                     </xenc:CipherData>
    //                 </xenc:EncryptedKey>
    //             </ds:KeyInfo>
    //             <xenc:CipherData xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
    //                 <xenc:CipherValue>R6l7tmbnXrOfBgB8lA3KnwLYsLH5ZO5omQ7Hp5K05atzw2o55xmCXVMYhNneFxMtxUh6raEyHeZX
    // 			PTZNgWrvdqc4GYND/R7MhRrJzk9OAq1WyoOXwbtRpwNDwWA4N2IuprPQJbvjVxaw/PesZMZwZqlp
    // 			...
    // 			zm9zAxahyu8Ooe8M4r3HN2cY0JxxxkZtDiulbnyA+rRtXfBRJtangvFQ4iFAnzM/Yg9hMyW9jcu0
    // 			S7FzuRB9ONMxi+nh0IFWgqp+</xenc:CipherValue>
    //             </xenc:CipherData>
    //         </xenc:EncryptedData>
    //     </saml2:EncryptedAssertion>
    // </saml2p:Response>

    // The sample encrypted SAML response and RSA private key are available online:
    CkHttpW http;
    CkStringBuilderW sbSamlResponse;
    CkStringBuilderW sbPrivateKeyPem;
    success = http.QuickGetSb(L"https://chilkatdownload.com/data/samlresponse.xml",sbSamlResponse);
    if (success == true) {
        success = http.QuickGetSb(L"https://chilkatdownload.com/data/samlresponse_privkey.pem",sbPrivateKeyPem);
    }

    if (success == false) {
        wprintf(L"%s\n",http.lastErrorText());
        return;
    }

    CkXmlW xml;
    xml.LoadSb(sbSamlResponse,true);

    // Load the RSA private key..
    CkPrivateKeyW privkey;
    success = privkey.LoadPem(sbPrivateKeyPem.getAsString());
    if (success == false) {
        wprintf(L"%s\n",privkey.lastErrorText());
        return;
    }

    // Prepare an RSA object w/ the private key...
    CkRsaW rsa;
    success = rsa.UsePrivateKey(privkey);
    if (success == false) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // RSA will be used to decrypt the xenc:EncryptedKey
    // The bytes to be decrypted are in xenc:CipherValue (in base64 format)
    const wchar_t *encryptedAesKey = xml.getChildContent(L"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue");
    if (xml.get_LastMethodSuccess() != true) {
        wprintf(L"Encrypted AES key not found.\n");
        return;
    }

    wprintf(L"Encrypted AES key (base64) = %s\n",encryptedAesKey);

    CkBinDataW bdAesKey;
    bdAesKey.AppendEncoded(encryptedAesKey,L"base64");

    CkStringBuilderW sbRsaAlg;
    sbRsaAlg.Append(xml.chilkatPath(L"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)"));
    wprintf(L"sbRsaAlg contains: %s\n",sbRsaAlg.getAsString());
    if (sbRsaAlg.Contains(L"rsa-oaep",true) == true) {
        rsa.put_PkcsPadding(false);
    }

    success = rsa.DecryptBd(bdAesKey,true);
    if (success == false) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    wprintf(L"Decrypted AES key (hex) = %s\n",bdAesKey.getEncoded(L"hex"));

    // Get the encrypted XML (in base64) to be decrypted w/ the AES key.
    const wchar_t *encrypted64 = xml.getChildContent(L"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue");
    if (xml.get_LastMethodSuccess() != true) {
        wprintf(L"Encrypted data not found.\n");
        return;
    }

    CkBinDataW bdEncrypted;
    bdEncrypted.AppendEncoded(encrypted64,L"base64");

    // Get the symmetric algorithm:  "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
    // and set the symmetric decrypt properties.
    CkCrypt2W crypt;
    CkStringBuilderW sbAlg;
    sbAlg.Append(xml.chilkatPath(L"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)"));
    if (sbAlg.Contains(L"aes128-cbc",true) == true) {
        crypt.put_CryptAlgorithm(L"aes");
        crypt.put_KeyLength(128);
        crypt.put_CipherMode(L"cbc");
        // The 1st 16 bytes of the encrypted data are the AES IV.
        crypt.SetEncodedIV(bdEncrypted.getEncodedChunk(0,16,L"hex"),L"hex");
        bdEncrypted.RemoveChunk(0,16);
    }

    // Other algorithms, key lengths, etc, can be supported by checking for different Algorithm attribute values..

    crypt.SetEncodedKey(bdAesKey.getEncoded(L"hex"),L"hex");

    // AES decrypt...
    success = crypt.DecryptBd(bdEncrypted);
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    // Get the decrypted XML
    const wchar_t *decryptedXml = bdEncrypted.getString(L"utf-8");
    wprintf(L"Decrypted XML:\n");
    wprintf(L"%s\n",decryptedXml);

    // The decrypted XML looks like this:

    // <saml2:Assertion xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" ID="_226e565c548db7986d165d7d969b48b4" IssueInstant="2018-10-11T17:46:20.727Z" Version="2.0">
    // ...
    // ...
    // ...
    // </saml2:Assertion>

    CkXmlW xmlAssertion;
    xmlAssertion.LoadXml(decryptedXml);

    // Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
    CkXmlW *xmlEncryptedAssertion = xml.FindChild(L"saml2:EncryptedAssertion");
    xmlEncryptedAssertion->SwapTree(xmlAssertion);
    delete xmlEncryptedAssertion;

    // The decrypted XML assertion has now replaced the encrypted XML assertion.
    // Examine the fully decrypted XML document:
    wprintf(L"Full XML SAML document with decrypted assertion:\n");
    wprintf(L"%s\n",xml.getXml());
    }