PHP Extension
PHP Extension
Decrypt a SAML Response
See more Encryption Examples
Demonstrates how to decrypt a SAML response.Chilkat PHP Extension Downloads
<?php
include("chilkat.php");
$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 = new CkHttp();
$sbSamlResponse = new CkStringBuilder();
$sbPrivateKeyPem = new CkStringBuilder();
$success = $http->QuickGetSb('https://chilkatdownload.com/data/samlresponse.xml',$sbSamlResponse);
if ($success == true) {
$success = $http->QuickGetSb('https://chilkatdownload.com/data/samlresponse_privkey.pem',$sbPrivateKeyPem);
}
if ($success == false) {
print $http->lastErrorText() . "\n";
exit;
}
$xml = new CkXml();
$xml->LoadSb($sbSamlResponse,true);
// Load the RSA private key..
$privkey = new CkPrivateKey();
$success = $privkey->LoadPem($sbPrivateKeyPem->getAsString());
if ($success == false) {
print $privkey->lastErrorText() . "\n";
exit;
}
// Prepare an RSA object w/ the private key...
$rsa = new CkRsa();
$success = $rsa->UsePrivateKey($privkey);
if ($success == false) {
print $rsa->lastErrorText() . "\n";
exit;
}
// RSA will be used to decrypt the xenc:EncryptedKey
// The bytes to be decrypted are in xenc:CipherValue (in base64 format)
$encryptedAesKey = $xml->getChildContent('saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue');
if ($xml->get_LastMethodSuccess() != true) {
print 'Encrypted AES key not found.' . "\n";
exit;
}
print 'Encrypted AES key (base64) = ' . $encryptedAesKey . "\n";
$bdAesKey = new CkBinData();
$bdAesKey->AppendEncoded($encryptedAesKey,'base64');
$sbRsaAlg = new CkStringBuilder();
$sbRsaAlg->Append($xml->chilkatPath('saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)'));
print 'sbRsaAlg contains: ' . $sbRsaAlg->getAsString() . "\n";
if ($sbRsaAlg->Contains('rsa-oaep',true) == true) {
$rsa->put_PkcsPadding(false);
}
$success = $rsa->DecryptBd($bdAesKey,true);
if ($success == false) {
print $rsa->lastErrorText() . "\n";
exit;
}
print 'Decrypted AES key (hex) = ' . $bdAesKey->getEncoded('hex') . "\n";
// Get the encrypted XML (in base64) to be decrypted w/ the AES key.
$encrypted64 = $xml->getChildContent('saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue');
if ($xml->get_LastMethodSuccess() != true) {
print 'Encrypted data not found.' . "\n";
exit;
}
$bdEncrypted = new CkBinData();
$bdEncrypted->AppendEncoded($encrypted64,'base64');
// Get the symmetric algorithm: "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
// and set the symmetric decrypt properties.
$crypt = new CkCrypt2();
$sbAlg = new CkStringBuilder();
$sbAlg->Append($xml->chilkatPath('saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)'));
if ($sbAlg->Contains('aes128-cbc',true) == true) {
$crypt->put_CryptAlgorithm('aes');
$crypt->put_KeyLength(128);
$crypt->put_CipherMode('cbc');
// The 1st 16 bytes of the encrypted data are the AES IV.
$crypt->SetEncodedIV($bdEncrypted->getEncodedChunk(0,16,'hex'),'hex');
$bdEncrypted->RemoveChunk(0,16);
}
// Other algorithms, key lengths, etc, can be supported by checking for different Algorithm attribute values..
$crypt->SetEncodedKey($bdAesKey->getEncoded('hex'),'hex');
// AES decrypt...
$success = $crypt->DecryptBd($bdEncrypted);
if ($success == false) {
print $crypt->lastErrorText() . "\n";
exit;
}
// Get the decrypted XML
$decryptedXml = $bdEncrypted->getString('utf-8');
print 'Decrypted XML:' . "\n";
print $decryptedXml . "\n";
// 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 = new CkXml();
$xmlAssertion->LoadXml($decryptedXml);
// Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
// xmlEncryptedAssertion is a CkXml
$xmlEncryptedAssertion = $xml->FindChild('saml2:EncryptedAssertion');
$xmlEncryptedAssertion->SwapTree($xmlAssertion);
// The decrypted XML assertion has now replaced the encrypted XML assertion.
// Examine the fully decrypted XML document:
print 'Full XML SAML document with decrypted assertion:' . "\n";
print $xml->getXml() . "\n";
?>