C
C
Decrypt a SAML Response
See more Encryption Examples
Demonstrates how to decrypt a SAML response.Chilkat C Downloads
#include <C_CkHttp.h>
#include <C_CkStringBuilder.h>
#include <C_CkXml.h>
#include <C_CkPrivateKey.h>
#include <C_CkRsa.h>
#include <C_CkBinData.h>
#include <C_CkCrypt2.h>
void ChilkatSample(void)
{
BOOL success;
HCkHttp http;
HCkStringBuilder sbSamlResponse;
HCkStringBuilder sbPrivateKeyPem;
HCkXml xml;
HCkPrivateKey privkey;
HCkRsa rsa;
const char *encryptedAesKey;
HCkBinData bdAesKey;
HCkStringBuilder sbRsaAlg;
const char *encrypted64;
HCkBinData bdEncrypted;
HCkCrypt2 crypt;
HCkStringBuilder sbAlg;
const char *decryptedXml;
HCkXml xmlAssertion;
HCkXml xmlEncryptedAssertion;
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:
http = CkHttp_Create();
sbSamlResponse = CkStringBuilder_Create();
sbPrivateKeyPem = CkStringBuilder_Create();
success = CkHttp_QuickGetSb(http,"https://chilkatdownload.com/data/samlresponse.xml",sbSamlResponse);
if (success == TRUE) {
success = CkHttp_QuickGetSb(http,"https://chilkatdownload.com/data/samlresponse_privkey.pem",sbPrivateKeyPem);
}
if (success == FALSE) {
printf("%s\n",CkHttp_lastErrorText(http));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
return;
}
xml = CkXml_Create();
CkXml_LoadSb(xml,sbSamlResponse,TRUE);
// Load the RSA private key..
privkey = CkPrivateKey_Create();
success = CkPrivateKey_LoadPem(privkey,CkStringBuilder_getAsString(sbPrivateKeyPem));
if (success == FALSE) {
printf("%s\n",CkPrivateKey_lastErrorText(privkey));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
return;
}
// Prepare an RSA object w/ the private key...
rsa = CkRsa_Create();
success = CkRsa_UsePrivateKey(rsa,privkey);
if (success == FALSE) {
printf("%s\n",CkRsa_lastErrorText(rsa));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
return;
}
// RSA will be used to decrypt the xenc:EncryptedKey
// The bytes to be decrypted are in xenc:CipherValue (in base64 format)
encryptedAesKey = CkXml_getChildContent(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue");
if (CkXml_getLastMethodSuccess(xml) != TRUE) {
printf("Encrypted AES key not found.\n");
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
return;
}
printf("Encrypted AES key (base64) = %s\n",encryptedAesKey);
bdAesKey = CkBinData_Create();
CkBinData_AppendEncoded(bdAesKey,encryptedAesKey,"base64");
sbRsaAlg = CkStringBuilder_Create();
CkStringBuilder_Append(sbRsaAlg,CkXml_chilkatPath(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)"));
printf("sbRsaAlg contains: %s\n",CkStringBuilder_getAsString(sbRsaAlg));
if (CkStringBuilder_Contains(sbRsaAlg,"rsa-oaep",TRUE) == TRUE) {
CkRsa_putPkcsPadding(rsa,FALSE);
}
success = CkRsa_DecryptBd(rsa,bdAesKey,TRUE);
if (success == FALSE) {
printf("%s\n",CkRsa_lastErrorText(rsa));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdAesKey);
CkStringBuilder_Dispose(sbRsaAlg);
return;
}
printf("Decrypted AES key (hex) = %s\n",CkBinData_getEncoded(bdAesKey,"hex"));
// Get the encrypted XML (in base64) to be decrypted w/ the AES key.
encrypted64 = CkXml_getChildContent(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue");
if (CkXml_getLastMethodSuccess(xml) != TRUE) {
printf("Encrypted data not found.\n");
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdAesKey);
CkStringBuilder_Dispose(sbRsaAlg);
return;
}
bdEncrypted = CkBinData_Create();
CkBinData_AppendEncoded(bdEncrypted,encrypted64,"base64");
// Get the symmetric algorithm: "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
// and set the symmetric decrypt properties.
crypt = CkCrypt2_Create();
sbAlg = CkStringBuilder_Create();
CkStringBuilder_Append(sbAlg,CkXml_chilkatPath(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)"));
if (CkStringBuilder_Contains(sbAlg,"aes128-cbc",TRUE) == TRUE) {
CkCrypt2_putCryptAlgorithm(crypt,"aes");
CkCrypt2_putKeyLength(crypt,128);
CkCrypt2_putCipherMode(crypt,"cbc");
// The 1st 16 bytes of the encrypted data are the AES IV.
CkCrypt2_SetEncodedIV(crypt,CkBinData_getEncodedChunk(bdEncrypted,0,16,"hex"),"hex");
CkBinData_RemoveChunk(bdEncrypted,0,16);
}
// Other algorithms, key lengths, etc, can be supported by checking for different Algorithm attribute values..
CkCrypt2_SetEncodedKey(crypt,CkBinData_getEncoded(bdAesKey,"hex"),"hex");
// AES decrypt...
success = CkCrypt2_DecryptBd(crypt,bdEncrypted);
if (success == FALSE) {
printf("%s\n",CkCrypt2_lastErrorText(crypt));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdAesKey);
CkStringBuilder_Dispose(sbRsaAlg);
CkBinData_Dispose(bdEncrypted);
CkCrypt2_Dispose(crypt);
CkStringBuilder_Dispose(sbAlg);
return;
}
// Get the decrypted XML
decryptedXml = CkBinData_getString(bdEncrypted,"utf-8");
printf("Decrypted XML:\n");
printf("%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>
xmlAssertion = CkXml_Create();
CkXml_LoadXml(xmlAssertion,decryptedXml);
// Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
xmlEncryptedAssertion = CkXml_FindChild(xml,"saml2:EncryptedAssertion");
CkXml_SwapTree(xmlEncryptedAssertion,xmlAssertion);
CkXml_Dispose(xmlEncryptedAssertion);
// The decrypted XML assertion has now replaced the encrypted XML assertion.
// Examine the fully decrypted XML document:
printf("Full XML SAML document with decrypted assertion:\n");
printf("%s\n",CkXml_getXml(xml));
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sbSamlResponse);
CkStringBuilder_Dispose(sbPrivateKeyPem);
CkXml_Dispose(xml);
CkPrivateKey_Dispose(privkey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdAesKey);
CkStringBuilder_Dispose(sbRsaAlg);
CkBinData_Dispose(bdEncrypted);
CkCrypt2_Dispose(crypt);
CkStringBuilder_Dispose(sbAlg);
CkXml_Dispose(xmlAssertion);
}