PureBasic Requires Chilkat v11.0.0+
PureBasic
Decrypt a SAML Response
See more Encryption Examples
Demonstrates how to decrypt a SAML response.Chilkat PureBasic Downloads
IncludeFile "CkBinData.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkHttp.pb"
IncludeFile "CkXml.pb"
IncludeFile "CkCrypt2.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRsa.pb"
Procedure ChilkatExample()
success.i = 0
; 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.i = CkHttp::ckCreate()
If http.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
sbSamlResponse.i = CkStringBuilder::ckCreate()
If sbSamlResponse.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
sbPrivateKeyPem.i = CkStringBuilder::ckCreate()
If sbPrivateKeyPem.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkHttp::ckQuickGetSb(http,"https://chilkatdownload.com/data/samlresponse.xml",sbSamlResponse)
If success = 1
success = CkHttp::ckQuickGetSb(http,"https://chilkatdownload.com/data/samlresponse_privkey.pem",sbPrivateKeyPem)
EndIf
If success = 0
Debug CkHttp::ckLastErrorText(http)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
ProcedureReturn
EndIf
xml.i = CkXml::ckCreate()
If xml.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkXml::ckLoadSb(xml,sbSamlResponse,1)
; Load the RSA private key..
privkey.i = CkPrivateKey::ckCreate()
If privkey.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkPrivateKey::ckLoadPem(privkey,CkStringBuilder::ckGetAsString(sbPrivateKeyPem))
If success = 0
Debug CkPrivateKey::ckLastErrorText(privkey)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
ProcedureReturn
EndIf
; Prepare an RSA object w/ the private key...
rsa.i = CkRsa::ckCreate()
If rsa.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkRsa::ckUsePrivateKey(rsa,privkey)
If success = 0
Debug CkRsa::ckLastErrorText(rsa)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
ProcedureReturn
EndIf
; RSA will be used to decrypt the xenc:EncryptedKey
; The bytes to be decrypted are in xenc:CipherValue (in base64 format)
encryptedAesKey.s = CkXml::ckGetChildContent(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue")
If CkXml::ckLastMethodSuccess(xml) <> 1
Debug "Encrypted AES key not found."
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
ProcedureReturn
EndIf
Debug "Encrypted AES key (base64) = " + encryptedAesKey
bdAesKey.i = CkBinData::ckCreate()
If bdAesKey.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkBinData::ckAppendEncoded(bdAesKey,encryptedAesKey,"base64")
sbRsaAlg.i = CkStringBuilder::ckCreate()
If sbRsaAlg.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkStringBuilder::ckAppend(sbRsaAlg,CkXml::ckChilkatPath(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)"))
Debug "sbRsaAlg contains: " + CkStringBuilder::ckGetAsString(sbRsaAlg)
If CkStringBuilder::ckContains(sbRsaAlg,"rsa-oaep",1) = 1
CkRsa::setCkPkcsPadding(rsa, 0)
EndIf
success = CkRsa::ckDecryptBd(rsa,bdAesKey,1)
If success = 0
Debug CkRsa::ckLastErrorText(rsa)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
CkBinData::ckDispose(bdAesKey)
CkStringBuilder::ckDispose(sbRsaAlg)
ProcedureReturn
EndIf
Debug "Decrypted AES key (hex) = " + CkBinData::ckGetEncoded(bdAesKey,"hex")
; Get the encrypted XML (in base64) to be decrypted w/ the AES key.
encrypted64.s = CkXml::ckGetChildContent(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue")
If CkXml::ckLastMethodSuccess(xml) <> 1
Debug "Encrypted data not found."
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
CkBinData::ckDispose(bdAesKey)
CkStringBuilder::ckDispose(sbRsaAlg)
ProcedureReturn
EndIf
bdEncrypted.i = CkBinData::ckCreate()
If bdEncrypted.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkBinData::ckAppendEncoded(bdEncrypted,encrypted64,"base64")
; Get the symmetric algorithm: "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
; and set the symmetric decrypt properties.
crypt.i = CkCrypt2::ckCreate()
If crypt.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
sbAlg.i = CkStringBuilder::ckCreate()
If sbAlg.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkStringBuilder::ckAppend(sbAlg,CkXml::ckChilkatPath(xml,"saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)"))
If CkStringBuilder::ckContains(sbAlg,"aes128-cbc",1) = 1
CkCrypt2::setCkCryptAlgorithm(crypt, "aes")
CkCrypt2::setCkKeyLength(crypt, 128)
CkCrypt2::setCkCipherMode(crypt, "cbc")
; The 1st 16 bytes of the encrypted data are the AES IV.
CkCrypt2::ckSetEncodedIV(crypt,CkBinData::ckGetEncodedChunk(bdEncrypted,0,16,"hex"),"hex")
CkBinData::ckRemoveChunk(bdEncrypted,0,16)
EndIf
; Other algorithms, key lengths, etc, can be supported by checking for different Algorithm attribute values..
CkCrypt2::ckSetEncodedKey(crypt,CkBinData::ckGetEncoded(bdAesKey,"hex"),"hex")
; AES decrypt...
success = CkCrypt2::ckDecryptBd(crypt,bdEncrypted)
If success = 0
Debug CkCrypt2::ckLastErrorText(crypt)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
CkBinData::ckDispose(bdAesKey)
CkStringBuilder::ckDispose(sbRsaAlg)
CkBinData::ckDispose(bdEncrypted)
CkCrypt2::ckDispose(crypt)
CkStringBuilder::ckDispose(sbAlg)
ProcedureReturn
EndIf
; Get the decrypted XML
decryptedXml.s = CkBinData::ckGetString(bdEncrypted,"utf-8")
Debug "Decrypted XML:"
Debug 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.i = CkXml::ckCreate()
If xmlAssertion.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkXml::ckLoadXml(xmlAssertion,decryptedXml)
; Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
xmlEncryptedAssertion.i = CkXml::ckFindChild(xml,"saml2:EncryptedAssertion")
CkXml::ckSwapTree(xmlEncryptedAssertion,xmlAssertion)
CkXml::ckDispose(xmlEncryptedAssertion)
; The decrypted XML assertion has now replaced the encrypted XML assertion.
; Examine the fully decrypted XML document:
Debug "Full XML SAML document with decrypted assertion:"
Debug CkXml::ckGetXml(xml)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbSamlResponse)
CkStringBuilder::ckDispose(sbPrivateKeyPem)
CkXml::ckDispose(xml)
CkPrivateKey::ckDispose(privkey)
CkRsa::ckDispose(rsa)
CkBinData::ckDispose(bdAesKey)
CkStringBuilder::ckDispose(sbRsaAlg)
CkBinData::ckDispose(bdEncrypted)
CkCrypt2::ckDispose(crypt)
CkStringBuilder::ckDispose(sbAlg)
CkXml::ckDispose(xmlAssertion)
ProcedureReturn
EndProcedure