add a Signature struct that can be used to make Signature templates

xmldsig/signature.go

@@ -0,0 +1,51 @@
+package xmldsig
+
+import "encoding/xml"
+
+// Method is part of Signature.
+type Method struct {
+	Algorithm string `xml:",attr"`
+}
+
+// Signature is a model for the Signature object specified by XMLDSIG. This is
+// convenience object when constructing XML that you'd like to sign. For example:
+//
+//    type Foo struct {
+//       Stuff string
+//       Signature Signature
+//    }
+//
+//    f := Foo{Suff: "hello"}
+//    f.Signature = DefaultSignature()
+//    buf, _ := xml.Marshal(f)
+//    buf, _ = Sign(key, buf)
+//
+type Signature struct {
+	XMLName xml.Name `xml:"http://www.w3.org/2000/09/xmldsig# Signature"`
+
+	CanonicalizationMethod Method   `xml:"SignedInfo>CanonicalizationMethod"`
+	SignatureMethod        Method   `xml:"SignedInfo>SignatureMethod"`
+	ReferenceTransforms    []Method `xml:"SignedInfo>Reference>Transforms>Transform"`
+	DigestMethod           Method   `xml:"SignedInfo>Reference>DigestMethod"`
+	DigestValue            string   `xml:"SignedInfo>Reference>DigestValue"`
+	SignatureValue         string   `xml:"SignatureValue"`
+	KeyName                string   `xml:"KeyInfo>KeyName"`
+}
+
+// DefaultSignature populates a default Signature that uses c14n and SHA1.
+func DefaultSignature() Signature {
+	return Signature{
+		CanonicalizationMethod: Method{
+			Algorithm: "http://www.w3.org/TR/2001/REC-xml-c14n-20010315",
+		},
+		SignatureMethod: Method{
+			Algorithm: "http://www.w3.org/2000/09/xmldsig#rsa-sha1",
+		},
+		ReferenceTransforms: []Method{
+			Method{Algorithm: "http://www.w3.org/2000/09/xmldsig#enveloped-signature"},
+		},
+		DigestMethod: Method{
+			Algorithm: "http://www.w3.org/2000/09/xmldsig#sha1",
+		},
+	}
+}