How to consume tokens from Infocard
So - if you’ve been wondering how my RP works...here’s an overview. I’m not going to cover declaring Policy or anything, as Mike Jones’ paper seems to have covered it in pretty good detail. I’m assuming here you can get InfoCard to invoke and POST a token.
To get started, you need to get your hands on the XML Token. This should be pretty simple, as your web framework will generally hand back parameters already URL decoded.
Once you’ve got the token, you’ll need to decrypt the token. The token is transmitted as encrypted XML, and will look something like this:
<enc:EncryptedData xmlns:enc="http://www.w3.org/2001/04/xmlenc#"
Type="http://www.w3.org/2001/04/xmlenc#Element">
<enc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes256-cbc" />
<dsig:KeyInfo xmlns:dsig="http://www.w3.org/2000/09/xmldsig#">
<enc:EncryptedKey>
<enc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p">
<dsig:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
</enc:EncryptionMethod>
<dsig:KeyInfo>
<wsse:SecurityTokenReference xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<wsse:KeyIdentifier ValueType="http://docs.oasis-open.org/wss/oasis-wss-soap-message-security-1.1#ThumbprintSHA1" EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary">zHXxYr8jTDe/UhznC81ixsQXSpI=</wsse:KeyIdentifier>
</wsse:SecurityTokenReference>
</dsig:KeyInfo>
<enc:CipherData>
<enc:CipherValue>hgBNzEXXnoLNu6DPhXJanirEPOK/ey53RKISJrwvRhQazPBgqcnZPaxNVqZf6TOR1VbryCU6fbGw
jIuuXzTb5Z+0PsRPM4N8CLSBxYxN1BFCNnhW67qJ4zrw72OTIkkTLWvPDpJpAak6X6RGFteaf3zD
uVYU4Ta0sDmMD6lxgjs=</enc:CipherValue>
</enc:CipherData>
</enc:EncryptedKey>
</dsig:KeyInfo>
<enc:CipherData>
<enc:CipherValue>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</enc:CipherValue>
</enc:CipherData>
</enc:EncryptedData>
Basically what you have here is an ephemeral symmetric encryption key, which has itself been encrypted with the Public Key of the SSL Cert for the website InfoCard is interacting with. As you can see from the metadata provided in the KeyInfo fragment, the key is encrypted using RSA with OAEP encoding and SHA1, using the certificate identified in the SecurityTokenReference with the provided fingerprint (the fingerprint is a SHA1 hash of the cert bytes)
Your first job is to decrypt that encryption key. Step one - remove the Base64 encoding. Step 2 - you need to write a function which takes the private key for the cert referenced by the fingerprint, along with the data as input, and decrypts in this manner RSA-OAEP
Once you’ve successfully decrypted the key ( it should be 256 bits), you can use it to decrypt the token. As you can see in the XML, you need to use AES with a ChainedBlockCipher. Decrypt the token (Don’t forget to strip the initialization vectors...thanks Gary ), and you should see something similar to the following:
<saml:Assertion MajorVersion="1" MinorVersion="1"
AssertionID="uuid:d2de97e7-96ac-4bb3-a373-4fc11c914519"
Issuer="http://schemas.microsoft.com/ws/2005/05/identity/issuer/self"
IssueInstant="2006-03-29T20:52:45.312Z" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion">
<saml:Conditions NotBefore="2006-03-29T20:52:45.312Z" NotOnOrAfter="2006-03-29T21:52:45.312Z" />
<saml:AttributeStatement>
<saml:Subject>
<saml:SubjectConfirmation>
<saml:ConfirmationMethod>urn:oasis:names:tc:SAML:1.0:cm:holder-of-key</saml:ConfirmationMethod>
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<e:EncryptedKey xmlns:e="http://www.w3.org/2001/04/xmlenc#">
<e:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p">
<DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
</e:EncryptionMethod>
<KeyInfo>
<o:SecurityTokenReference xmlns:o="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<o:KeyIdentifier ValueType="http://docs.oasis-open.org/wss/oasis-wss-soap-message-security-1.1#ThumbprintSHA1" EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary">BCDy8bwQIxTqcoTObIhcvR2KOLw=</o:KeyIdentifier>
</o:SecurityTokenReference>
</KeyInfo>
<e:CipherData>
<e:CipherValue>XjkCVuQZ19sYbSnEeKYQ7wD/+bKvGL6kkS2yuVjQX4y3N7U86zRJ66njNPdFNdh8k/x+5CNF1rpjq/Be75a1skO9ePjLgik/UA1DlDo9jaFoYvRlEj0BN/TPJaMZ24kcmcG+QeU89rdg0S4+bqxytHyh14m6IaIaX4aj88RRVq4=</e:CipherValue>
</e:CipherData>
</e:EncryptedKey>
</KeyInfo>
</saml:SubjectConfirmation>
</saml:Subject>
<saml:Attribute AttributeName="GivenName" AttributeNamespace="http://schemas.microsoft.com/ws/2005/05/identity/claims">
<saml:AttributeValue>Mister</saml:AttributeValue>
</saml:Attribute>
<saml:Attribute AttributeName="Surname" AttributeNamespace="http://schemas.microsoft.com/ws/2005/05/identity/claims">
<saml:AttributeValue>Milo</saml:AttributeValue>
</saml:Attribute>
<saml:Attribute AttributeName="EmailAddress" AttributeNamespace="http://schemas.microsoft.com/ws/2005/05/identity/claims">
<saml:AttributeValue>milo@xmldap.org</saml:AttributeValue>
</saml:Attribute>
</saml:AttributeStatement>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo>
<CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
<SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
<Reference URI="#uuid:d2de97e7-96ac-4bb3-a373-4fc11c914519">
<Transforms>
<Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
<Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
</Transforms><DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
<DigestValue>leav91ZV/KJpwumP/j+4XtlEvJg=</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue>gEVmREMwNiE67hMdOf7uuC4jnhG4f9y3WYL2pL6d9F3Nblf3qddMe6K+d/b6ucePKS3Q9XXBmBu2tWtmZlwTzldVjx8IYZb5u5jcQByAp2GrTJb/XxHA/3BkE073zdFRlmHje467kVd4Mcg6X2qNsV1N+euZqCUfmrXyf3cs5n4u6A9A1CTuQhCOGhE7jjDUGPmyChJa2YfHqpiVPEXgqN+RYOTLUFbA2kKj1Jyi8+FJD7vHP/5/kblge82waNFOOaA6d7lXDhr4lBDDhr5vKoNWy91bDMStn+nKN7Nzj7zPjxjynp7CisSewyWxAjcD9XDl/I9Va2UVDmPr4JC4bw==</SignatureValue>
<KeyInfo>
<KeyValue>
<RSAKeyValue>
<Modulus>rCOb7lDap18tsTurz6j/fSYnO+ck5or10hn9tZhCDwXfJip2lqjIFcj3fYv1cyP96dl4++x8QGXSB5WAu3NNtjZkVxTDO4sOk+IpkLOlE5vM6ClMSV46tx9fo6tbQ9EhJTy7vXAbCH6hQnowxdmUEVKJudCtlMeHSotix98T5zJXYMjeLvmDPmSK8pG/t+kBmRjsgSZGqjD4VFlnDBpYOZ4R+nH2ESudyvZUwAkgPAEtGuBcc+nXVUEbs+O1xOkzcTRCm9FCoww1oNSi2maRGontD14Cbyy3DuNRxqPSxEc8rN7KBoq5w2y+Q5YTVYBB+qn2rXbO0aQlYHXIZOATpw==</Modulus>
<Exponent>AQAB</Exponent>
</RSAKeyValue>
</KeyValue>
</KeyInfo>
</Signature>
</saml:Assertion>
The next step would be to quickly check the validity period on this Assertion to make sure it’s still fresh. You might also want to check the AssertionID against a table of previously seen assertions to prevent replay...depends on your level of paranoia.
On to signature validation...you should follow the steps outlined in XML-DSIG, but to paraphrase, check the digest of the canonicalized assetion against the digest in the SignedInfo block, and then valhttp://www.blogger.com/img/gl.link.gifidate the signature of the canonicalized SignedInfo using a PublicKey constructed from the provided KeyInfo.
Now, what’s bugging me is the use for the Symmetric Proof key provided in the Subject of the Assertion. Super Pat and I discussed this for awhile, and since it’s not used immediately in this protocol exchange, our best guess is that it’s used in subsequent interactions with the service, although I must admit the InfoCard docs are a little fuzzy on this subject. If anyone can fill me in, I’d appreciate it!
Finally, if your signature validation worked, extract the claims, enforce any policy you’d like, create a session, set a cookie, etc...
good luck!
