When using xml signatures the whole xml document is jumbled

Question

I am using xml signatures to validate saml request :

The initial saml request before signing :

<samlp:AuthnRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" ID
="abc" Version="2.0" IssueInstant="2012-04-14T8:55:05:31" ProtocolBinding="urn:o
asis:names:tc:SAML:2.0:bindings:HTTP-POST" AssertionConsumerServiceURL="http://l
ocalhost:8080/consumer.jsp"><saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0
:assertion">http://localhost:8080/saml/SProvider.jsp</saml:Issuer></samlp:AuthnR
equest>

After signing the xml document and then converting it into string(using transformer) I am getting the following:

    <?xml version="1.0" encoding="UTF-8" standalone="no"?><samlp:AuthnReques
    t xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" AssertionConsumerServiceURL
    ="http://localhost:8080/consumer.jsp" ID="abc" IssueInstant="2012-04-14T8:55:05:
    31" ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Version="2.
    0"><saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">http://localh
    ost:8080/saml/SProvider.jsp</saml:Issuer><Signature xmlns="http://www.w3.org/200
    0/09/xmldsig#"><SignedInfo><CanonicalizationMethod Algorithm="http://www.w3.org/
    TR/2001/REC-xml-c14n-20010315#WithComments"/><SignatureMethod Algorithm="http://
    www.w3.org/2000/09/xmldsig#rsa-sha1"/><Reference URI=""><Transforms><Transform A
    lgorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/></Transforms><
    DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><DigestValue>J
    QV+Gff3C0PDb5zbaB62ItqWaJ/yIFgOVfANUehlJpQ=</DigestValue></Reference></SignedInf
    o><SignatureValue>PJCFgkGUlQiOVn6g0hTgbbHkqOGAKB5sA8QjcdKrR5R9zuyn9ymfFZMo1jqpxU
   //#here 3UOCz1BcxsWt6+ 
    CSFSAS0SaQstuN8ns/5ltIYu3LFUrpIT4eRHxbYEjf+CFj0c08lFB+BLK3Tx3vEi7nQF+X1rUvZX
    XZEUmaAMLqNdhRSqurY=</SignatureValue></Signature></samlp:AuthnRequest>

As you can see the first attribute in the initial string is ID But after signing the first attrubute is AssertionConsumerServiceURL. Why is getting jumbled? Moreover in the signed document see #here(third line from last), there is a line break. Why is there a line break.I don't think encrypted values contain line breaks. I don't understand what is happening. Please help.

score 2 · Answer 1 · edited May 23 '17 at 12:02

2

In order for a signature to be calculated, the XML file must be canonicalized. It must be in a standard format for the receiving application to verify the signature.

But, I don't think it needs to be sent canonicalized; since the receiving application must also canonicalize the XML to calculate the signature for verification. So, you can try to reformat it after signing it. But I don't know if that will work, so test it thoroughly.

edited May 23 '17 at 12:02

Community

1
1

answered Apr 14 '12 at 03:31

Jordão

55,340
13
112
144

Thanks for responding. But I have canonicalised using "with comments". If you want to I will put up the code also that I have used. – Ashwin Apr 14 '12 at 03:39
"with comments" just means that it will preserve your XML comments, of which you don't have any... – Jordão Apr 14 '12 at 03:46
So what should I do. I mean which algorithm should I use? – Ashwin Apr 14 '12 at 03:51
Formating will only make it more oresentable. I want to know why is it getting jumbled. And moreover I am am not able to read the element Issuer in my server. – Ashwin Apr 14 '12 at 04:52

score 1 · Accepted Answer · edited May 23 '17 at 10:08

1

Refer this link. error due to xml signature . Most of it says that xml signatures cannot guarantee you the ordering of the xml tags. It also says that this is due to the canonicalization. But I am not sure of that. One thing I came to know is that it is not uncommon when using xml signatures.

edited May 23 '17 at 10:08

Community

1
1

answered Apr 18 '12 at 05:23

Ashwin

12,691
31
118
190

When using xml signatures the whole xml document is jumbled

2 Answers2