(AutoIt) Decrypt a SAML Response

Demonstrates how to decrypt a SAML response.

Note: This example requires Chilkat v9.5.0.76 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

; 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:
$oHttp = ObjCreate("Chilkat.Http")
$oSbSamlResponse = ObjCreate("Chilkat.StringBuilder")
$oSbPrivateKeyPem = ObjCreate("Chilkat.StringBuilder")
Local $bSuccess = $oHttp.QuickGetSb("https://chilkatdownload.com/data/samlresponse.xml",$oSbSamlResponse)
If ($bSuccess = True) Then
    $bSuccess = $oHttp.QuickGetSb("https://chilkatdownload.com/data/samlresponse_privkey.pem",$oSbPrivateKeyPem)
EndIf

If ($bSuccess <> True) Then
    ConsoleWrite($oHttp.LastErrorText & @CRLF)
    Exit
EndIf

$oXml = ObjCreate("Chilkat.Xml")
$oXml.LoadSb($oSbSamlResponse,True)

; Load the RSA private key..
$oPrivkey = ObjCreate("Chilkat.PrivateKey")
$bSuccess = $oPrivkey.LoadPem($oSbPrivateKeyPem.GetAsString())
If ($bSuccess <> True) Then
    ConsoleWrite($oPrivkey.LastErrorText & @CRLF)
    Exit
EndIf

; Prepare an RSA object w/ the private key...
$oRsa = ObjCreate("Chilkat.Rsa")
$bSuccess = $oRsa.ImportPrivateKeyObj($oPrivkey)
If ($bSuccess <> True) Then
    ConsoleWrite($oRsa.LastErrorText & @CRLF)
    Exit
EndIf

; RSA will be used to decrypt the xenc:EncryptedKey
; The bytes to be decrypted are in xenc:CipherValue (in base64 format)
Local $sEncryptedAesKey = $oXml.GetChildContent("saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue")
If ($oXml.LastMethodSuccess <> True) Then
    ConsoleWrite("Encrypted AES key not found." & @CRLF)
    Exit
EndIf

ConsoleWrite("Encrypted AES key (base64) = " & $sEncryptedAesKey & @CRLF)

$oBdAesKey = ObjCreate("Chilkat.BinData")
$oBdAesKey.AppendEncoded($sEncryptedAesKey,"base64")

$oSbRsaAlg = ObjCreate("Chilkat.StringBuilder")
$oSbRsaAlg.Append($oXml.ChilkatPath("saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)"))
ConsoleWrite("sbRsaAlg contains: " & $oSbRsaAlg.GetAsString() & @CRLF)
If ($oSbRsaAlg.Contains("rsa-oaep",True) = True) Then
    $oRsa.OaepPadding = True
EndIf

; Note: The DecryptBd method is introduced in Chilkat v9.5.0.76
$bSuccess = $oRsa.DecryptBd($oBdAesKey,True)
If ($bSuccess <> True) Then
    ConsoleWrite($oRsa.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Decrypted AES key (hex) = " & $oBdAesKey.GetEncoded("hex") & @CRLF)

; Get the encrypted XML (in base64) to be decrypted w/ the AES key.
Local $sEncrypted64 = $oXml.GetChildContent("saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue")
If ($oXml.LastMethodSuccess <> True) Then
    ConsoleWrite("Encrypted data not found." & @CRLF)
    Exit
EndIf

$oBdEncrypted = ObjCreate("Chilkat.BinData")
$oBdEncrypted.AppendEncoded($sEncrypted64,"base64")

; Get the symmetric algorithm:  "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
; and set the symmetric decrypt properties.
$oCrypt = ObjCreate("Chilkat.Crypt2")
$oSbAlg = ObjCreate("Chilkat.StringBuilder")
$oSbAlg.Append($oXml.ChilkatPath("saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)"))
If ($oSbAlg.Contains("aes128-cbc",True) = True) Then
    $oCrypt.CryptAlgorithm = "aes"
    $oCrypt.KeyLength = 128
    $oCrypt.CipherMode = "cbc"
    ; The 1st 16 bytes of the encrypted data are the AES IV.
    $oCrypt.SetEncodedIV $oBdEncrypted.GetEncodedChunk(0,16,"hex"),"hex"
    $oBdEncrypted.RemoveChunk(0,16)
EndIf

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

$oCrypt.SetEncodedKey $oBdAesKey.GetEncoded("hex"),"hex"

; AES decrypt...
$bSuccess = $oCrypt.DecryptBd($oBdEncrypted)
If ($bSuccess <> True) Then
    ConsoleWrite($oCrypt.LastErrorText & @CRLF)
    Exit
EndIf

; Get the decrypted XML
Local $sDecryptedXml = $oBdEncrypted.GetString("utf-8")
ConsoleWrite("Decrypted XML:" & @CRLF)
ConsoleWrite($sDecryptedXml & @CRLF)

; 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>

$oXmlAssertion = ObjCreate("Chilkat.Xml")
$oXmlAssertion.LoadXml($sDecryptedXml)

; Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
Local $oXmlEncryptedAssertion = $oXml.FindChild("saml2:EncryptedAssertion")
$oXmlEncryptedAssertion.SwapTree($oXmlAssertion)

; The decrypted XML assertion has now replaced the encrypted XML assertion.
; Examine the fully decrypted XML document:
ConsoleWrite("Full XML SAML document with decrypted assertion:" & @CRLF)
ConsoleWrite($oXml.GetXml() & @CRLF)