Lua Requires Chilkat v11.0.0+
Lua
Decrypt a SAML Response
See more Encryption Examples
Demonstrates how to decrypt a SAML response.Chilkat Lua Downloads
local chilkat = require("chilkat")
-- 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:
local http = chilkat.Http.new()
local sbSamlResponse = chilkat.StringBuilder.new()
local sbPrivateKeyPem = chilkat.StringBuilder.new()
local success = http:quick_get_sb("https://chilkatdownload.com/data/samlresponse.xml", sbSamlResponse)
if success then
success = http:quick_get_sb("https://chilkatdownload.com/data/samlresponse_privkey.pem", sbPrivateKeyPem)
end
if not success then
print(http.last_error_text)
return
end
local xml = chilkat.Xml.new()
xml:load_sb(sbSamlResponse, true)
-- Load the RSA private key..
local privkey = chilkat.PrivateKey.new()
success = privkey:load_pem(sbPrivateKeyPem:get_as_string())
if not success then
print(privkey.last_error_text)
return
end
-- Prepare an RSA object w/ the private key...
local rsa = chilkat.Rsa.new()
success = rsa:use_private_key(privkey)
if not success then
print(rsa.last_error_text)
return
end
-- RSA will be used to decrypt the xenc:EncryptedKey
-- The bytes to be decrypted are in xenc:CipherValue (in base64 format)
local encryptedAesKey = xml:get_child_content("saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:CipherData|xenc:CipherValue")
if not xml.last_method_success then
print("Encrypted AES key not found.")
return
end
print("Encrypted AES key (base64) = " .. encryptedAesKey)
local bdAesKey = chilkat.BinData.new()
bdAesKey:append_encoded(encryptedAesKey, "base64")
local sbRsaAlg = chilkat.StringBuilder.new()
sbRsaAlg:append(xml:chilkat_path("saml2:EncryptedAssertion|xenc:EncryptedData|ds:KeyInfo|xenc:EncryptedKey|xenc:EncryptionMethod|(Algorithm)"))
print("sbRsaAlg contains: " .. sbRsaAlg:get_as_string())
if sbRsaAlg:contains("rsa-oaep", true) then
rsa.pkcs_padding = false
end
success = rsa:decrypt_bd(bdAesKey, true)
if not success then
print(rsa.last_error_text)
return
end
print("Decrypted AES key (hex) = " .. bdAesKey:get_encoded("hex"))
-- Get the encrypted XML (in base64) to be decrypted w/ the AES key.
local encrypted64 = xml:get_child_content("saml2:EncryptedAssertion|xenc:EncryptedData|xenc:CipherData|xenc:CipherValue")
if not xml.last_method_success then
print("Encrypted data not found.")
return
end
local bdEncrypted = chilkat.BinData.new()
bdEncrypted:append_encoded(encrypted64, "base64")
-- Get the symmetric algorithm: "http://www.w3.org/2001/04/xmlenc#aes128-cbc"
-- and set the symmetric decrypt properties.
local crypt = chilkat.Crypt2.new()
local sbAlg = chilkat.StringBuilder.new()
sbAlg:append(xml:chilkat_path("saml2:EncryptedAssertion|xenc:EncryptedData|xenc:EncryptionMethod|(Algorithm)"))
if sbAlg:contains("aes128-cbc", true) then
crypt.crypt_algorithm = "aes"
crypt.key_length = 128
crypt.cipher_mode = "cbc"
-- The 1st 16 bytes of the encrypted data are the AES IV.
crypt:set_encoded_iv(bdEncrypted:get_encoded_chunk(0, 16, "hex"), "hex")
bdEncrypted:remove_chunk(0, 16)
end
-- Other algorithms, key lengths, etc, can be supported by checking for different Algorithm attribute values..
crypt:set_encoded_key(bdAesKey:get_encoded("hex"), "hex")
-- AES decrypt...
success = crypt:decrypt_bd(bdEncrypted)
if not success then
print(crypt.last_error_text)
return
end
-- Get the decrypted XML
local decryptedXml = bdEncrypted:get_string("utf-8")
print("Decrypted XML:")
print(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>
local xmlAssertion = chilkat.Xml.new()
xmlAssertion:load_xml(decryptedXml)
-- Replace the saml2:EncryptedAssertion XML subtree with the saml2:Assertion XML.
local xmlEncryptedAssertion = xml:find_child("saml2:EncryptedAssertion")
xmlEncryptedAssertion:swap_tree(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:")
print(xml:get_xml())