Query a signed XML-DSIG document

Get the CanonicalizationMethod and SignatureMethod algorithms

> xmlsq "//ds:CanonicalizationMethod/@Algorithm" example-obj-signed.xml
http://www.w3.org/TR/2001/REC-xml-c14n-20010315

> xmlsq "//ds:SignatureMethod/@Algorithm" example-obj-signed.xml
http://www.w3.org/2000/09/xmldsig#rsa-sha1

How many Reference elements?

> xmlsq --count "//ds:Reference" example-obj-signed.xml
2

Extract the digest values

> xmlsq  "(//ds:Reference)[1]/ds:DigestValue" example-obj-signed.xml
J+9NBdXdULEOhvdxSRtx5f+QUBE=

> xmlsq  "(//ds:Reference)[2]/ds:DigestValue" example-obj-signed.xml
qznsyVqM2sgMCpKnQnqhsnL8wDU=

Extract the second URI reference

> xmlsq "(//ds:Reference)[2]/@URI" example-obj-signed.xml
#obj-b

Extract the contents of the reference

> xmlsq //*[@Id='obj-b'] example-obj-signed.xml
More content.

Extract the first URI reference, URI=""

> xmlsq "(//ds:Reference)[1]/@URI" example-obj-signed.xml
 

Oh! This is an attribute with an empty value. Use the --delim option to see the result more clearly.

> xmlsq  --delim=' "(//ds:Reference)[1]/@URI" example-obj-signed.xml
''
> xmlsq  --delim=[] "(//ds:Reference)[1]/@URI" example-obj-signed.xml
[]

Check the full query result.

> xmlsq -f "(//ds:Reference)[1]/@URI" example-obj-signed.xml
URI=""

Extract the SignatureValue

> xmlsq //ds:SignatureValue example-obj-signed.xml
xgYGwedYZKJ0QhBJ9XdB0XekSqIk+HYdH+leK4plE6PEt49cTK+t0AwIt7Q/ctn/vHTVC/pirFf+KrcmIxPsvP
FMQDEpx+Rx7RyN7RlvWeeyHYvf64Uk20refVdnja4PVNCXNmiQtFTQrgbBcK/WVS0NnJdAYmq6yzLDDDcKYTc=

Use the "local-name" predicate.

> xmlsq --count "//*[local-name()='Reference']" example-obj-signed.xml
2